Xie v R

1. [1]

   THE COURT: On the morning of 18 July 2009, police were called to attend a four‑bedroom home on Boundary Road, North Epping, a suburb in the north west of Sydney. On the second floor of the home they were confronted with a scene of unspeakable brutality. Spread across three bedrooms were the bludgeoned bodies of five members of the Lin family: Min (Norman) Lin and his wife Yun Li (Lily) Lin, Lily’s younger sister Yun Bin (Irene) Lin, and Min and Lily’s two sons, Henry Lin and Terry Lin. At the time of their deaths, Henry and Terry were aged 12 years and 9 years respectively. Their 15‑year‑old sister, Brenda Lin, [1] was not home. She had travelled to New Caledonia on a school excursion. [2]

2. [2]

   Min Lin had a younger sister, Kathy Lin. Kathy Lin and her husband, Lian Bin (Robert) Xie, lived nearby on Beck Street, North Epping with their son, XX. [3] Robert Xie is the applicant for leave to appeal against his conviction. (As leave will be granted, he will be referred to as the appellant.) After an intensive police investigation, on 11 May 2011 he was charged with five counts of murder. He stood trial in the Supreme Court before Johnson J and a jury twice in 2014 but both trials were aborted (the first and second 2014 trials respectively). He was tried again before Fullerton J and a jury in 2015 but the jury was discharged after being unable to reach a verdict (the 2015 trial).

3. [3]

   On 28 June 2016, the appellant was arraigned before Fullerton J and a jury panel. He pleaded not guilty and his fourth trial commenced with a jury of 15 (the 2016 trial). The jury was reduced to twelve persons just prior to deliberations commencing. On 12 January 2017, majority verdicts of guilty were returned on all counts. As an indication of the size and complexity of the 2016 trial, the summing up took place over eight days between 15 December 2016 and 29 December 2016. The transcript of the trial runs to 6,465 pages.

4. [4]

   On 13 February 2017, Fullerton J sentenced the appellant to imprisonment for life; that is, for the term of his natural life (R v Xie [2017] NSWSC 63).

5. [5]

   The appellant appeals his convictions on eight grounds. The first three grounds of appeal concern the admission and use of certain evidence from an expert witness, Dr Mark Perlin, concerning the likely contributors to a stain containing DNA from multiple persons that was found in the appellant’s garage (“Stain 91”). (The swab taken from Stain 91 became known as “item 550” [4] ). Grounds 4, 5 and 6 complain about aspects of the trial judge’s summing up at the 2016 trial. Ground 7 concerns the admission of coincidence evidence concerning similarities between a homemade massage device and an item the Crown theorised was the murder weapon. Ground 8 contends that, in various respects that mostly correspond with parts of Grounds 1 to 7, the appellant’s counsel at the 2016 trial was incompetent such that a miscarriage of justice was occasioned by his acts and omissions.

6. [6]

   In considering those grounds it must be borne in mind that a criminal trial is an accusatory and adversarial process in which the prosecution and the defence, not the Court, are responsible for determining the issues in the trial and the evidence to be adduced (Ratten v The Queen (1974) 131 CLR 510 at 517; [1974] HCA 35; “Ratten”; TKJW v The Queen (2002) 212 CLR 124; [2002] HCA 46 at [106] per Hayne J; “TKWJ”). Further, the forum for the identification and resolution of those issues is the trial before the jury and not the appellate court. Leaving aside the form of review undertaken by this Court when it is contended that a verdict of guilty is “unreasonable, or cannot be supported, having regard to the evidence” (Criminal Appeal Act 1912, s 6(1)), which was not the case here, in addressing whether a trial was unfair this Court does not conduct its own form of retrial, does not reformulate the issues of fact identified by the parties at the trial and generally does not speculate about how the conduct of the trial might have been conducted differently or better. The principles governing an appeal from a conviction to this Court admit of exceptions to this such that, in some circumstances, issues and evidence that were not raised at trial can be raised and adduced on appeal respectively. However, those exceptions are limited.

7. [7]

   The evidence the subject of challenge by Grounds 1 to 3 and parts of Ground 8 concerns the outcome and meaning of a computer based probabilistic analysis of a mixed DNA sample. The deployment of such evidence in a criminal trial might be considered novel, even controversial. Whether or not that is so is of no present relevance. This Court was obliged to consider the challenges to that evidence in a context where that evidence was not contradicted by other evidence at the 2016 trial and only partly challenged by other evidence sought to be adduced on appeal. As explained below, the bulk of the complaints raised on behalf of the appellant in relation to this evidence concern matters that were not raised at the 2016 trial and in many respects involve an attempt to unravel decisions made by the counsel who appeared for the appellant at that trial. In this Court, the appellant sought to overcome the difficulties that raises by attempting to invoke the exceptions just noted and otherwise contending that his counsel’s conduct of the trial caused a miscarriage of justice. For the reasons set out below these attempts, along with the complaints about the admissibility and use of evidence from Dr Perlin, must be rejected.

8. [8]

   A similar difficulty arises with part of ground 5(b) which complains about the fairness of a factual summary provided by the trial judge to the jury concerning various aspects of the appellant’s conduct that the Crown contended demonstrated a “consciousness of guilt”. One theme of the appellant’s submissions in respect of this ground was that the trial judge failed to put the “real defence case” to the jury. [5] This was not a reference to the case run on behalf of the appellant at the 2016 trial but to a different characterisation of the evidence formulated on appeal. However, it was no part of the trial judge’s function to discern some different case and direct the jury accordingly. In McKell v The Queen (2019) 264 CLR 307 (“McKell”) Bell, Keane, Gordon and Edelman JJ discussed the (limited) circumstances in which a trial judge might comment on the facts of a case in the context of the “duty of a trial judge to assist the jury with a fair and accurate statement of the case presented by the parties” (at [48]). In any event, for the reasons set out below the trial judge’s summing up in this respect was not unfair or lacking in balance.

9. [9]

   As explained below, the complaints made in relation to ground 6 which concern the trial judge’s directions to the jury in respect of the appellant's alibi were also not raised at the trial. Even allowing for that we do not consider that any miscarriage of justice was occasioned by those directions or by the directions the subject of complaint by grounds 4 and 5(a). We conclude that the coincidence evidence the subject of complaint by ground 7 was admissible. We reject the contention raised by ground 8 that the conduct of the appellant’s counsel at the 2016 trial occasioned a miscarriage of justice. It follows from these conclusions that the appeal against conviction must be dismissed.

10. [10]

    To explain these conclusions, it is first necessary to outline some of the factual circumstances concerning the killings, as well as the Crown and defence cases.

PART 1: Background

1. [11]

   Min Lin was 45 years old at the time of his death and his wife Lily Lin was 44 years old. They migrated separately to Australia from the Peoples Republic of China (the “PRC”) in 1989. They were married in July 1995 and had three children: Brenda, born the previous year, Henry, born in 1997 and Terry, born in 2000. Lily Lin’s sister Irene Lin was 39 years old at the time of her death. She entered Australia in 2008 on a student visa and lived with the Lin family. [6] For a number of years Min and Lily Lin operated the Epping Central Newsagency on Rawson Street, Epping.

2. [12]

   At the time of the killings Kathy Lin, Min Lin’s sister, and the appellant were 40 years old and 45 years old respectively. They were married in the PRC in December 1998. By that time Kathy Lin had migrated to Australia. The appellant came to Australia on a spouse visa the following year. XX was born in 2000. [7]

3. [13]

   Min and Kathy Lin’s parents, Yang Fei Lin and Feng Quin Zhu (the “grandparents”), migrated to Australia from the PRC in 1996. From 2000 they lived in a home in Merrylands purchased by Min and Lily Lin. [8]

Friday 17 July 2009

1. [14]

   To all outward appearances the Xie and Lin families were close. Min and Lily Lin purchased their home on Boundary Road in January 2001 (the “Boundary Road home”). Kathy Lin and the appellant bought their home on Beck Street in October 2005 (the “Beck Street home”). The distance between the two houses was 300 metres.

2. [15]

   Members of both families attended a regular dinner at the grandparents’ home on Friday nights, including on the evening of Friday, 17 July 2009.

3. [16]

   A forensic analysis of a personal computer found by police in the dining room near the kitchen of the Boundary Road home reveals that it was shut down at 6.03pm on the evening of 17 July 2009. [9] About ten minutes prior, Henry Lin sent a message on the computer to his badminton coach saying he was leaving for his grandparents’ home as “I go every Friday”. [10]

4. [17]

   In a recorded interview that Kathy Lin conducted with the police on 20 July 2009 (the “July 2009 interview”) she told them that the appellant drove her, their son XX, as well as Henry and Terry Lin, to the grandparents’ house for dinner. Min Lin arrived at the grandparents’ house separately. [11] Lily and Irene Lin did not attend the dinner. As noted, Brenda Lin was overseas on a school trip in New Caledonia. [12] According to Kathy Lin, Min Lin left the dinner at around 9:30pm. [13]

5. [18]

   At around 10.00pm the appellant and Kathy Lin drove XX, Henry and Terry Lin home from dinner. [14] Camera footage shows their car travelling towards the Boundary Road home at 10.13pm. [15] At around 10.23pm Henry Lin commenced exchanging computer messages with his badminton coach. [16] Between that time and around 12.02am, a laptop computer in his room and the computer downstairs in the dining room were used to exchange messages, conduct internet searches and play “on‑line” games. Both computers were shut down at around midnight. [17]

6. [19]

   Kathy Lin told the police that, after they returned to the Beck Street home, XX went to bed at around 10:45pm. She and the appellant then read newspapers, watched TV, viewed the internet and went to bed “after 2.00am”. [18]

Saturday 18 July 2009

1. [20]

   Mr Lakhwinder Sing Hothi was supposed to work at Min and Lily Lin’s newsagency in Epping on the morning of 18 July 2019. He had arranged to meet Min Lin at the newsagency at 6.35am but it was closed when he arrived and Min Lin was not present. [19] He telephoned Min Lin three times between 6.50am and 8.01am but there was no answer. [20] Mr Zhi Liang (Jason) Ge owned the Epping Fruit Market, which was nearby to the newsagency. At around 8:30am, a regular customer of the newsagency told Mr Ge that the newsagency had not opened. Mr Ge obtained a mobile phone number for Min Lin from the real estate agent. At around 9.32am he tried to telephone Min Lin but he did not answer. He then telephoned Kathy Lin. [21]

2. [21]

   In her July 2009 interview, Kathy Lin told the police that she woke up at around 8.00am on Saturday, 18 July 2009. [22] She said that at “[a]round, after 9.30[am]” she received a telephone call from the man who owned the fruit market near Min Lin’s newsagency, who said, “[w]hat’s wrong with your brother’s shop. No one opened the shop and no one deliver the newspaper”. [23] She said she also received a telephone call from a customer of the newsagency, Mr Hua, who asked her why no one had opened the newsagency that morning. [24] That call was made at around 9.36am. [25] She immediately telephoned her brother but again there was no answer.

3. [22]

   Kathy Lin told police that at around 10.00am, she and the appellant drove to the Boundary Road home. [26] She said they parked in front of the house and “left [XX] in the car”. She and the appellant knocked loudly on the door but no one answered. After looking in the dining area and the laundry, Kathy Lin and the appellant went upstairs. In her July 2009 interview she told the police: [27]

4. [23]

   In his interview with police on 22 July 2009, the appellant said that after dropping XX at the Beck Street home, he returned to the house on Boundary Road. He said that his wife was standing on the intersection of the driveway and the road making phone calls and kept telling him, “[l]et’s pick up my parents”. The appellant said they decided that Kathy Lin would stay at Boundary Road to wait for the police and the appellant would travel to Merrylands and pick up the grandparents. [29]

5. [24]

   Three triple zero calls were made by Kathy Lin that morning at 9:47am, 9:48am and 9:54am. [30] They were all recorded and played to the jury. She was distressed throughout the calls. In the second call she told the operator that “maybe someone killed, killed my brother, my brother’s family”. [31] Towards the end of the first call, Kathy Lin and the appellant discussed his taking XX back to the Beck Street home. In the second call Kathy Lin told the appellant in Cantonese, “[d]oesn’t matter, just ring and get [indecipherable] to come here by himself/herself/themselves”. She also told him three times that she was “scared”. After the sound of her husband driving away is heard, she is recorded as saying “[h]ey, husband”. [32]

6. [25]

   The appellant’s mother‑in‑law, Mrs Zhu, told the police that “a little bit before 10.00am” her husband, Mr Lin Snr, received a call from the appellant. After the telephone call, her husband told her to stop washing the dishes, that the appellant had said something had happened with Min Lin’s family and that they had to leave in a hurry. [33] She said that the appellant arrived at their home in Merrylands about 10-20 minutes after the telephone call.

7. [26]

   On the morning of 18 July 2009, Senior Constable Kirby and Constable Levins were driving a fully marked police vehicle. At around 9.53am they heard a police radio broadcast about an incident at Boundary Road. [34] They arrived within a “matter of minutes”. [35] Senior Constable Kirby saw Kathy Lin standing at the top of a driveway, waving to them. Senior Constable Kirby confirmed with Kathy Lin that she was the person who had telephoned triple‑0. When he asked Kathy Lin what had happened she said, “I think my brother’s dead inside”. Senior Constable Kirby then asked, “[w]hy do you think your brother is dead?” and she replied, “[t]he real estate called me and said my brother hasn’t gone to work. I came over and knocked on the door. No-one answered so I went inside. I went upstairs and saw my sister-in-law was dead”. [36]

8. [27]

   Senior Constable Kirby and Constable Levins drew their firearms, entered the house and went upstairs. [37] Senior Constable Kirby took a step inside what he described as “Bedroom 2” [38] and located the body of Irene Lin “with extensive trauma to her face lying on the bed”. [39] Constable Levins entered what was described as “Bedroom 1” and called out to SC Kirby. Senior Constable Kirby took a “couple of steps inside” and saw another body “lying on the left side of the bed closest to the window” which at the time he believed to be male but he later learnt was Lily Lin. [40] Senior Constable Kirby then entered “Bedroom 3” but only “one step in” and saw two deceased “children lying on the floor”. [41] Senior Constable Kirby then undertook what he described as a “quick sweep” of the living room and kitchen downstairs [42] before leaving the house and advising the ambulance officers who arrived that there were four bodies inside. [43] Senior Constable Kirby then re‑entered the house with the ambulance officers who checked the children for pulses before leaving the house. [44]

9. [28]

   After a short time, SC Kirby’s shift supervisor, Sergeant Crow, arrived. He accompanied SC Kirby back into the house where they ascertained that the body on the left side of the bed in Bedroom 1 was female, that is Lily Lin. [45] At around this time, Sergeant Johnstone arrived at the scene and entered the house with Sergeant Crow. They did not discover Min Lin’s body either. [46]

10. [29]

    As the police were unaware that Min Lin was dead at this time, they considered him a suspect. In the meantime, at 10.55am the appellant arrived at the Boundary Road home with the grandparents. [47] Mr Lin Snr’s evidence from the 2015 trial was replayed to the jury at the 2016 trial. [48] He said that Kathy Lin told him that Lily, Irene and the two children had been murdered. [49] Mr Lin Snr said he asked “[d]id you see your brother?” and Kathy Lin replied “[n]o I did not”. Mr Lin Snr said that the appellant then said to Mrs Zhu, “[a]t most, we could take Brenda as our adopted daughter”. Mr Lin Snr said, “[n]o, that’s not possible when grandparents are still around, you are not allowed to take her as an adopted daughter”. Mr Lin Snr said he thought “of that [statement] as a consolation why he [the appellant] said that”. [50]

11. [30]

    Later that morning the grandparents travelled to Hornsby Hospital in an ambulance. The appellant and Kathy Lin dropped XX at a friend’s house and followed them. A friend of the Xie family gave evidence that at around 11.47am on the morning of 18 July 2009 she answered a call to her landline from the appellant, who asked if XX could come to her house to play with her son. [51] About 15 minutes later, the appellant, Kathy Lin and XX arrived.

12. [31]

    At around midday, crime scene officers arrived at the Boundary Road home. [52] Senior Constable Kirby entered the garage and attempted to turn on a light but realised there was no power at the house. [53]

13. [32]

    At around 1.45pm, two Detectives attended Hornsby Hospital. The evidence concerning the events of this day that led to the discovery of the body of Min Lin are described below in relation to Ground 5. [54] It suffices to state that the two detectives spoke to a nurse who had previously spoken to Kathy Lin. The detectives then spoke to Kathy Lin with a staff member of the hospital interpreting. At some point one of the Detectives asked Kathy Lin, “[w]e need to find Min. Do you have any idea where he could be?” Kathy Lin replied, “[h]e’s in the bed in the house”. She was asked whether she saw him and responded, “[t]here’s a lump in the bed where he sleeps. I went to the room, I saw the blood and the lump. I went to pull the cover down but my husband pulled me out and said ‘No don’t look’”. [55] Detective Senior Constable Wilson told that jury that this was said in a very insistent manner (“she was making a statement and she actually looked at us like, ‘of course he’s in there’”.) Detective Senior Constable Wilson said that at this time the appellant was sitting next to Kathy Lin and he “gave the appearance of listening”, but he was “basically looking at the floor or the wall”. [56]

14. [33]

    At about 2.00pm, Sergeant Johnstone received information about the body of Min Lin being in Bedroom 1 from an officer at the scene who had been in contact with DSC Wilson. Wearing protective suits, he and SC Kirby, inspected Bedroom 1 and located Min Lin’s body under a doona. [57]

15. [34]

    The family friend gave evidence that Kathy Lin and the appellant returned at about 6.00pm to pick up XX. When she collected XX, Kathy Lin told the family friend that four members of her brother’s family had passed away. [58]

Location of the Bodies

1. [35]

   A layout of the second floor of the Boundary Road home showing the location of the bodies is as follows: [59]

Police Investigation

1. [36]

   The officer‑in‑charge of the police investigation was Detective Sergeant Maree. As noted, both the appellant [60] and Kathy Lin [61] voluntarily participated in interviews with police in July 2009.

2. [37]

   Detective Sergeant Maree gave evidence that after November 2009, the appellant became the focus of the police investigation because the police had received information that he was seeking custody of Brenda Lin and had involved himself in the estate of Min and Lily Lin. [62]

3. [38]

   The NSW Crime Commission became involved with the police investigation in the latter part of 2009. On 9 December 2009, warrants were obtained to access the appellant’s landline and mobile telephone.

4. [39]

   In early 2010, DS Maree arranged for an application to be made to the Supreme Court for a warrant authorising police to place covert surveillance devices in the Beck Street home. On 19 January 2010, police officers covertly entered the home and installed the devices. On 8 February 2010, police officers commenced recording conversations at the home.

5. [40]

   On 16 March 2010, the appellant was again interviewed by police [63] as was Kathy Lin on 22 March 2010. [64]

6. [41]

   On 10 May 2010, some of the covert surveillance devices were discovered by the appellant and stopped working. As a result, police obtained and executed a warrant to search the Beck Street home. The search of the home was completed on 15 May 2010. Late in the afternoon on 13 May 2010, Stain 91 was discovered on the floor of the garage. [65]

7. [42]

   On 11 May 2011, DS Maree arrested the appellant at the Beck Street home. Thereafter he was remanded in custody until he was released on bail on 8 December 2015 after the 2015 trial concluded. Between early 2012 and February 2013, the appellant was placed in custody in close proximity to a police informer, “Witness A”, who was later called by the Crown to give evidence of his conversations with the appellant. Transcripts of six recorded conversations between Witness A and the appellant between May 2012 and November 2012 were tendered at the 2016 trial. [66]

PART 2: The Crown Case

1. [43]

   The following precis of the Crown case and that of the appellant is taken from the summing up of the trial judge delivered to the jury at the 2016 trial. Save for the matters raised by the grounds of appeal, it is not suggested that her Honour failed to put either case fairly or accurately.

2. [44]

   The Crown case against the appellant was circumstantial. It had three overall steps. First, the Crown sought to exclude the possibility that the murders were the result of a robbery, theft, or sexual assault “gone wrong”. Second, the Crown sought to prove that they were the work of a single assailant. Third, the Crown sought to prove that the appellant was the single assailant.

3. [45]

   In relation to the first step, the Crown relied on the fact that there was no evidence of drawers or the like having been disturbed and that there were valuables in the house left untouched. A forensic pathologist, Dr Rebecca Irvine, found no evidence of sexual assault on any of the deceased. [67] The Crown also submitted that the lack of friction ridge detail on finger marks in blood suggested that the killer was wearing gloves, a matter pointing to this having been a well‑planned, rather than spontaneous, crime. [68] The Crown also led evidence of the breadth of the police investigation in order to establish that all other lines of inquiry had been pursued. [69]

4. [46]

   In relation to the second step, the Crown relied on the evidence of Dr Irvine as well as two crime scene experts, Dr Jennifer Raymond and Detective Sergeant Shawn Harkins.

5. [47]

   The effect of the evidence of Dr Raymond and DS Harkins was that there was evidence at the crime scene of only one murder weapon. [70] The evidence of Dr Irvine was that Min, Lily, Terry and Henry Lin were all killed by a combination of blunt force injury to the head and asphyxia. [71] Irene Lin was killed by blunt force injury to the head. Blunt force injury to the head and asphyxia can both cause rapid incapacitation. [72] All five deceased showed signs of having been attacked with the same hammer-like implement. [73]

6. [48]

   Dr Raymond’s analysis of the shoe marks at the crime scene indicated that 20 of 41 shoe marks identified bore an unusual and distinctive sole pattern. [74] Of the remaining 21 shoe marks, there were only three that Dr Raymond was unable to eliminate conclusively as having been caused by crime scene contamination. [75] These included a Nike TN Air Max shoe mark that was not in blood and found partially under the “red car bed” in Bedroom 1, [76] a shoe mark that was possibly in blood in the foyer [77] and a shoe mark in dust in the foyer. [78] The Crown contended that the shoe marks in dust were unlikely to have had anything to do with the murders. The shoe mark that was possibly in blood was pointing towards the stairs, suggesting it was a contamination mark. [79] It followed, according to the Crown, that the only shoe marks at the scene attributable to the crime were worn by a single person.

7. [49]

   In relation to the third step, namely demonstrating that the appellant was that sole killer, the Crown relied on twelve circumstances.

8. [50]

   The first circumstance that the Crown relied on was the absence of evidence of any forced entry into the Boundary Road home. A locksmith, Mr Ross Squire, told the Court that there was no evidence of the lock to the front door having been interfered with and he had never seen a lock that had been picked without leaving a trace. [80] The appellant had access to a key to the Boundary Road home. [81] This key was handed over to police by Kathy Lin and examined by Mr Squire, who found evidence that it had been used to cut another key. [82]

9. [51]

   The second circumstance that the Crown relied on was that the electricity to the house was turned off before the murders in order to prevent any of the victims from turning any lights on if they awoke. It would follow that the murders occurred in the dark, which the Crown contended meant that the killer must have been familiar with the layout of the house, as the applicant was. [83]

10. [52]

    The third circumstance that the Crown relied on was that the crime scene photographs showed Bedroom 4, Brenda Lin’s room, to be completely undisturbed. By contrast, there were marks in blood, not only on the carpet but on doors and also walls of the other three bedrooms from what seemed to be a hanging rope, suggesting that the killer had moved between them. [84] The appellant knew that Brenda Lin was not at home that night. [85]

11. [53]

    The fourth circumstance that the Crown relied on was that the 20 shoe marks left by the killer, noted above, were an “ASICS”-brand sole pattern type that the company had used on only three models of shoe, including the Gel Evation II. [86] That sole pattern had not been used by ASICS since 2005. Dr Raymond’s opinion was that the size of the relevant ASICS shoe was between 8.5 and 10.5. [87] The appellant had owned a pair of Gel Evation II ASICS sports shoes [88] and his size was a 9.5. [89]

12. [54]

    The fifth circumstance that the Crown relied on was that a folded piece of cloth, soaked in Min and Lily Lin’s blood and bound with a red rubber band, was found in Bedroom 3 (ie, the children’s bedroom). The Crown case was that it must have been affixed at one point to the murder weapon and had come loose possibly during an intense struggle with Terry Lin in Bedroom 3. Although the murder weapon was not found, on the evidence of DS Harkins it must have been a highly unusual handmade device involving rope attached to a hammer-like object. [90]

13. [55]

    Police found a massage device at the appellant’s home that was also a highly unusual, handmade device. [91] It included a long steel bolt to which a folded piece of cloth had been attached with a red rubber band. In both cases, the pieces of cloth had been placed over a hard, cylindrical object, so as to create circular depressions in the cloth. The Crown relied on the similarity between these two devices and the pieces of cloth affixed to them by means of red rubber bands [92] as coincidence evidence connecting the appellant to the murders. [93] The admission and use of this evidence is the subject of complaint by Ground 7.

14. [56]

    The sixth circumstance that the Crown relied on was that all of the deceased, apart from Irene Lin, showed evidence of neck compression. [94] The appellant had trained as a doctor in PRC, specialising in the ear, nose and throat. According to the Crown, the appellant would have had knowledge of the structure of the neck and the ability to inflict rapidly incapacitating injury by means of neck compression. [95] The Crown relied on a covertly recorded conversation between the appellant and “Witness A” in which, according to the Crown, the appellant acknowledged having shown Witness A how to incapacitate someone with pressure points on the neck. [96] The Crown also relied on evidence of the appellant’s high level of fitness and arm strength from playing badminton as demonstrative of his ability to inflict the sorts of injuries suffered by the deceased. [97]

15. [57]

    The seventh matter that the Crown relied on concerned various aspects of the conduct of the appellant on the morning of 18 July 2009 which were said to be evidence of his guilt. Some of this conduct is considered later in relation to Ground 5(b). The conduct included him telling XX to wait in the car and then his following closely behind Kathy Lin as she moved around the house. [98] It also included him hugging Kathy Lin and telling her not to look into Bedroom 1. [99] The Crown contended that, having regard to the configuration of that bedroom, this displayed a prior knowledge by the appellant of the presence of bodies in that room. The Crown contended that a surveillance device later captured the appellant telling Kathy Lin what to say about where they were standing and what they could see. [100]

16. [58]

    The Crown also contended that the appellant’s insistence on collecting the grandparents, even though his wife was hysterical and scared, indicated that he was aware that there was no ongoing danger in the Boundary Road home and he used the journey to the grandparents’ home as a pretext to dispose of the murder weapon. The Crown relied on a recorded conversation between the appellant and Witness A in which the appellant disclosed a belief that the person who found the bodies would become the main suspect and another conversation which the Crown contended contained an implied admission by the appellant to having disposed of the murder weapon while travelling to collect the grandparents on the morning of 18 July 2009 (see [63]). [101]

17. [59]

    The Crown also contended that on 18 July 2009 the appellant made no real attempt to check to see if the children were still alive, notwithstanding his medical training and particular attachment to Henry Lin. [102] It also referred to his offer to the grandparents to adopt Brenda Lin before Min Lin’s body had been discovered. [103] Further, the Crown contended that, at some point during 18 June 2009, the appellant told Kathy Lin that Min Lin’s body was under the doona on the bed in Bedroom 1, knowledge the Crown contended he must have acquired from being the murderer.

18. [60]

    The eighth circumstance that the Crown relied on was that, after the murders, Mr Lin Snr was concerned about the safety of the surviving family members living in the Beck Street home and bought security devices, but the appellant told him that this was unnecessary. [104]

19. [61]

    The ninth circumstance that the Crown relied on was a statement made by the appellant in an interview with police on 16 March 2010 in which he said that when he entered Bedroom 1, he “saw Lily and Min this side”. [105] The following day, he called the officer‑in‑charge and told him that he always said that there could be four or five bodies in the house and that he had told a Chinese-speaking police officer at the scene the same thing. That officer, Mr Andrew Ting, denied that the appellant had told him this. [106] The Crown contended that the appellant inadvertently disclosed that he had seen Min Lin’s dead body in the bed and then tried to cover up his mistake. [107]

20. [62]

    The tenth circumstance that the Crown relied on was surveillance evidence of the appellant destroying shoeboxes on the night of 6 May 2010. This occurred immediately after Kathy Lin appeared at the NSW Crime Commission, during which she was told by investigators of their belief that the killer had been wearing ASICS shoes in the appellant’s size. The surveillance footage showed the appellant, later that night, cutting up shoeboxes into pieces, soaking them in a bucket of water and then flushing them down the toilet. [108] The appellant admitted that was what he was doing in the footage. [109] The Crown contended that this evinced a consciousness of guilt. [110] This and the next matter are relevant to Ground 5(a).

21. [63]

    The eleventh matter the Crown relied on was the appellant’s interactions with Witness A, which were also said to evince a consciousness of guilt. [111] This included recorded conversations in which the appellant accepted offers from Witness A to obtain inside information from a supposedly corrupt official involved in the police investigation. For example, one of the recorded conversations took place on 13 October 2012 and involved Witness A discussing with the appellant the possibility that inside information could be procured as to whether the prosecution had obtained incriminating CCTV footage. [112] Witness A referred to the possibility of the prosecution obtaining footage of the appellant travelling to the grandparents’ house on the morning of 18 July 2009. [113] Later, Witness A refers to the appellant preparing something to respond to any CCTV footage or having it “removed”: [114]

22. [64]

    The Crown contended that this and the balance of the conversation was an implied admission by the appellant that he disposed of the murder weapon when he collected the grandparents on the morning of 18 July 2009.

23. [65]

    The evidence from Witness A relied on by the Crown also included evidence that the appellant pursued a plan with Witness A to plant incriminating evidence in the house of a deceased person to frame that person for the murders (referred to in the trial as “Plan B”). In pursuit of this plan, the Crown contended the appellant gave a number of documents to Witness A, including handwritten notes that could have been used to have a key cut to the Boundary Road home and put in the home or in the belongings of an interested person. [115]

24. [66]

    Lastly, the Crown relied upon the discovery of “Stain 91” in the appellant’s garage on 13 May 2010. The (extensive) evidence concerning Stain 91 is summarised below in relation to Grounds 1 to 3. At this point it suffices to state that, based on the evidence of an expert DNA analyst, Mr Clayton Walton, and Dr Perlin, the Crown contended that Stain 91 was a blood stain that contained DNA from each of Min, Terry, Henry and Irene Lin. The evidence from Dr Perlin included the results of the application of the “TrueAllele” software that he developed. TrueAllele performs a probabilistic analysis of mixed DNA samples. The Crown submitted that the presence of DNA from each of Min, Terry, Henry and Irene Lin in Stain 91 was only explicable on the basis that it was brought back to the Beck Street home by the appellant on the night of the murders and transferred from some item to the garage floor. [116] ”

25. [67]

    Two further matters should be mentioned about the Crown case. The first matter concerns alibi. Kathy Lin gave evidence that she and the appellant went to bed at around 2.00am on 18 July 2009. She said her husband “didn’t get off the bed” that night. She agreed she could not recall if she woke, but said that if her husband woke up she would know (“he’s next to me, if he wake up, he will move, and he will walk”). She said she did not feel sedated before going to sleep. Kathy Lin said she woke up at around 8:00am on the Saturday morning and her husband rose from his bed at the same time. [117]

26. [68]

    The evidence relied on by the Crown to disprove the appellant’s alibi is summarised below in relation to ground 6. [118] At this point it suffices to state that in order to disprove alibi, the Crown relied on the contents of Kathy Lin’s interview with police on 22 March 2010. In that interview she was asked, inter alia, whether “your husband, Robert, get out of bed that night?” and she replied “I don't know”. [119] The Crown also relied on a transcript of a surveillance device recording of 22 March 2010, [120] in which she stated “[w]ho can remember waking up or not on that night? He or she asked if that night, er, woke up how many times, huh, sometimes wake up and sometimes don't. How do I know?”. [121] The Crown submitted that Kathy Lin was untruthful in her evidence in saying that she was sure the appellant had never left the bed and that she was tailoring her evidence to assist him. [122]

27. [69]

    The Crown also relied on evidence from Brenda Lin, who lived with the appellant’s family after the murders, to the effect that the appellant regularly sexually assaulted her at night. [123] This was said to be evidence that the appellant could leave his wife’s bed without her knowledge. The Crown also pointed to evidence from Witness A that the appellant had told him that he had sedated his wife on the night of the murders. [124] The Crown relied on a recorded conversation with Witness A in which Witness A said, “[t]he weak, the strong thing for police in your case, believe me, is always the wife. Always. And your wife is no problem, you told me before … when the murder happened your wife sedated, so that’s, forget about it”. The appellant said, “[y]eah …”. Witness A said, “[t]here is nothing they can do” and the applicant replied, “[n]othing, nothing”. [125] The trial judge’s directions in relation to alibi are the subject of Ground 6.

28. [70]

    The second matter concerns motive. The Crown relied on the appellant’s sexual assault of Brenda Lin as evidence of a possible motive. [126] It also led evidence of possible motive via the recorded conversations with Witness A in which the appellant spoke in highly disparaging terms about Min Lin [127] and of his own perceived subordinate status within the family (“they tell Kathy she can get better husband more beautiful than me, more success”; “they believe their son smartest”). [128]

29. [71]

    The evidence of Dr Irvine indicated that the injuries to Min and Lily Lin were far more severe than the injuries inflicted upon Irene Lin and the children. The Crown relied on this evidence to submit that Min and Lily Lin were the primary victims of the killer, [129] and that Irene Lin and the two boys were only killed when they woke up and it became necessary to silence them. [130]

PART 3: The Defence Case

1. [72]

   On behalf of the appellant it was contended that it was manifestly improbable that one person could have killed all five deceased given the difficulty involved in incapacitating such a large number of people. [131] The defence pointed to the different types of injuries inflicted on the five deceased (and their varying severity). [132] The defence relied on unidentified shoe marks in the house, an unidentified fingerprint on the front door, unidentified DNA on the electricity box and unidentified DNA on some cigarette butts in the driveway as giving rise to the real possibility of a second assailant. [133]

2. [73]

   The defence submitted that DS Harkins’ opinions were limited to blood-letting injuries and there remained the possibility that non blood-letting injuries could have been inflicted elsewhere in the house. [134] It was also submitted that the evidence left open the possibility that Lily and Irene Lin were killed while the other family members were at dinner at the grandparents’ house, and that the killers lay in wait at the Boundary Road home for the other family members to get home. [135] The defence relied on evidence of shouting heard by neighbours at around 10.00pm, which was said to be consistent with an assault on Min Lin upon his arrival home. [136]

3. [74]

   The defence contended that the killer or killers intended to kill all five family members. [137] It was submitted that Irene or Lily Lin may actually have let the killers in earlier in the night, thereby explaining the lack of forced entry. [138] Alternatively, it was submitted that a light tap on a “bump key” could have been used without necessarily leaving any traces. [139] It was submitted that the appellant would not have been as foolish to have used his own key to the house. [140]

4. [75]

   It was submitted that the appellant’s ownership of “ASICS Gel Evation II” shoes was not incriminating, in circumstances where many other people in Australia had also purchased those shoes (or had purchased the other two ASICS models that had also used that sole pattern). [141] The defence case was that the appellant had destroyed the shoeboxes not out of a consciousness of guilt but out of a fear of being framed. [142]

5. [76]

   Contrary to the Crown case, it was submitted that there was nothing about the appellant’s conduct on 18 July 2009 that was incriminating. [143] Instead, it was submitted that his conduct was neutral, [144] especially having regard to the extreme shock and horror he must have been experiencing at that time. [145]

6. [77]

   It was submitted that Kathy Lin had always believed Min Lin’s body might be inside the house. [146] Photographic evidence demonstrated that the appellant was substantially taller than Kathy Lin, so he could well have been able to see over her in order to see the body of Lily Lin before she did. [147] The defence contended that when the appellant left the scene, his wife was in no danger, being some distance away from the house and in the midst of a busy Saturday morning in Epping. [148] The appellant did not “take the opportunity” of disposing of the murder weapon by going to the grandparents’ house. He did not want to go to pick them up but, instead he called them and suggested they come by train. [149] The defence submitted that there was also no time to travel there, return and dispose of the murder weapon. [150] The defence noted that police did not find blood in the red Corolla he had allegedly stashed the weapon in. [151] It was also submitted that the conversation about adopting Brenda Lin never happened. [152]

7. [78]

   The defence submitted that the Crown had not succeeded in disproving the appellant’s alibi beyond a reasonable doubt. [153] It was submitted that Kathy Lin was a witness of truth. [154] It was submitted that it was inconceivable that the appellant could have been sexually assaulting Brenda Lin at night without her noticing. [155]

8. [79]

   The defence pointed to the very short timeframe in which, on the Crown case, the appellant had to commit these murders given that he and his wife went to bed at 2.00am and, on Brenda Lin’s evidence, Min Lin could rise as early as 4.00am. [156]

9. [80]

   The defence relied on evidence that the appellant had a good relationship with the Lin family, especially his particular fondness for 12-year-old Henry, who shared his passion for badminton.

10. [81]

    It was submitted that the recorded conversations with Witness A did not contain admissions and were no more than “gaol talk”. [157] It was submitted that he never actually pursued “Plan B” (and never gave the “key documents” to Witness A). [158] In particular, it was contended that the response “yeah” in the conversation with Witness A was not an acknowledgement of having sedated his wife. [159] Otherwise, it was submitted that Witness A was a liar and a seasoned criminal whose evidence should not be accepted. [160] As far as the Plan B evidence is concerned, it was submitted that the appellant was an intelligent man who would never have contemplated such an absurd plan. [161]

11. [82]

    The defence submitted that the murder weapon and massage device were not relevantly similar [162] and that if the appellant had left the cloth at the crime scene he would not have left the massage device in plain sight in his house at a time when he knew he had become a suspect. [163]

12. [83]

    It was submitted that Brenda Lin had invented the sexual assault allegations in order to provide the Crown case with evidence of motive [164] and that her fondness for the appellant, as expressed in some cards to him, was inconsistent with her allegations. [165]

13. [84]

    As to Stain 91, the defence submitted that the Crown could not establish that it was blood. [166] It was contended that substances that might give rise to false positive results could well be in a garage, [167] and there had been some false positive reactions that day. [168] As explained below, at the 2016 trial the defence accepted that DNA from Min, Terry and Henry Lin was present in Stain 91, [169] but submitted that Brenda Lin’s DNA was also present in the stain or at least that was a reasonable possibility. It was submitted that, if there was any (reasonable) chance that Brenda Lin was a contributor to Stain 91, then this meant that the Crown had failed to prove that the stain was blood or was otherwise incriminating. [170]

14. [85]

    Further, it was submitted that innocent secondary transfer was a real and not speculative possibility to explain the DNA evidence, given the connection between the Lin and Xie families. [171] It was pointed out that the swab taken from Stain 91 for DNA testing may have been taken from outside the borders of the stain, raising the possibility that the DNA detected was not from the stain. [172] It was also submitted that the jury should be disinclined to accept Dr Perlin’s evidence about match statistics given that a report by the (US) President’s Council of Advisors on Science and Technology [173] (“the President’s Report” [174] ) did not accept that TrueAllele had been validated for more than three contributors. The defence also relied on the fact that Dr Perlin was a “privateer” with a financial incentive to insist on TrueAllele’s accuracy. [175]

15. [86]

    Finally, the defence submitted that the appellant’s interviews with police demonstrated his willingness to assist, [176] even when he had become a suspect. [177] The defence called character witnesses and relied on good character. [178] It was suggested that what was known of the appellant was inconsistent with the nature of these crimes.

PART 4: Dr Perlin’s Evidence and Stain 91

1. [87]

   The first three grounds of the appeal all concern Dr Perlin’s evidence. They provide:

2. [88]

   Ground 1 refers to a judgment given by Johnson J prior to the first 2014 trial but following a lengthy voir‑dire that addressed, inter alia, the admissibility of Dr Perlin’s evidence (R v Xie (No 4) [2014] NSWSC 500; “Xie (No 4)”).

3. [89]

   Ground 8 of the appeal contends that a miscarriage of justice was occasioned by a number of acts and omissions of the appellant’s counsel at the 2016 trial. The first six particulars of this ground concern the conduct of counsel in relation to Dr Perlin’s evidence, namely:

4. [90]

   As will be explained, the bulk of the submissions in support of Grounds 1 to 3 and the above particulars to Ground 8 concern issues that were not raised at the 2016 trial (or the 2015 trial) and in many respects are flatly inconsistent with the manner in which the 2016 trial was conducted. The appellant also sought to rely on evidence that was adduced at the hearing of the appeal from Dr Perlin [179] and a Forensic DNA expert, Professor Peter Gill. [180] All of that evidence was only received by this Court provisionally, that is, on the basis that its admissibility would be determined in the substantive judgment. [181] This approach was adopted because of both the complexity of the material and the fact that the appellant alleged that Dr Perlin had conducted himself dishonestly. [182] The provisional admission of all the evidence sought to be adduced on appeal afforded Dr Perlin the opportunity to fully respond to the serious allegations made against him.

Discovery of Stain 91

1. [91]

   As noted, late in the afternoon of 13 May 2010, a stain that became known as Stain 91 was discovered on an area of the floor of the garage at the Beck Street home. It was located on the floor, in a location previously covered by a “tallboy”, by forensic biologists Ms Melanie Le Compte, Ms Nicole Campbell and Ms Jae Gerhard. [183] It was an elliptical shape, approximately 2cm long and 6mm at its widest point and described as having a “dark grey/brown staining/disclouration”. [184]

2. [92]

   At the scene an “O‑tol” test was performed on the stain which produced a strong reaction (“dark, intense blue colour”). [185] The forensic biologists who found Stain 91 thought that it looked like an aged bloodstain. Presumptive testing of the stain was positive for blood, with the strength of the reaction indicating that it was more likely than not to have been a true positive. [186]

Mr Walton’s Evidence on DNA Testing

1. [93]

   At the time of the 2016 trial, Mr Walton was the acting manager of the NSW Forensic and Analytical Science Service (“FASS”) which was formerly known as the Division of Analytical Laboratories (“DAL”). He holds an Honours degree in science and has worked as a DNA analyst since 2001. Neither at the trial, nor on appeal, was there any challenge to his expertise or his evidence. Mr Walton gave evidence on three occasions during the 2016 trial. On the second occasion he explained his analysis of Stain 91. [187] On the third occasion he was recalled to address various matters that arose during the evidence of Dr Perlin.

2. [94]

   On the first occasion that he gave evidence, Mr Walton explained DNA and DNA analysis as follows. [188] A deoxyribonucleic acid (or DNA) double helix is the fundamental unit of genetic material. Each cell of the human body, other than red blood cells, has a nucleus. Inside the nucleus there are 23 pairs of chromosomes each of which consists of a segment of DNA [189] of different length. [190] One of the chromosomal pairs determines gender. Biological females have two X chromosomes and males have one X and one Y chromosome. The remaining 22 pairs of chromosomes determine various human characteristics. Each member of the pair of chromosomes is inherited from one parent. [191]

3. [95]

   Specific areas on the DNA strand are known as locus. Those areas that contain coding information, such as hair colour and eye colour, are known as genes. [192] DNA testing focuses on the non‑coding areas as they contain differences between individuals that aid identification of a person’s DNA. [193] The relevant form of testing for this case involves detecting Short Tandem Repeats (“STR”), that is, analysing these loci and determining the number of repetitions of a particular combination of the four “bases” of DNA (Adenine, Thymine, Guanine and Cytosine) at that location. [194]

4. [96]

   Three tests adopted in NSW laboratories over time were the “Profiler Plus”, which examines 9 loci plus an area that determines biological gender, the Identifiler Kit, which examines 15 loci plus an area that determines biological gender and the “PowerPlex 21”, which examines 20 loci plus an area that determines biological gender. [195] Most of the loci examined with the PowerPlex 21 were located on different chromosomes although, according to Mr Walton, “[t]here is a couple on the same chromosome”. [196] In addition, there is a “Y filer” test which examines only the Y chromosome passed from fathers to sons, [197] specifically 16 “areas” or loci on the Y chromosome. [198]

5. [97]

   At each locus, each person has two DNA sequences known as alleles, one from each parent. [199] Across the population at that locus there are many different alleles as measured by STR. [200] One sense of the phrase “genotype” is to describe a pair of alleles at a particular locus. [201] For example, at a particular locus a person may have a genotype of “10,12” meaning that there were “10” and “12” short tandem repeats of a particular combination of four bases at that locus. [202] Another sense of the phrase “genotype” is to describe the collection of pairs of alleles for a particular DNA sample, which in the case of PowerPlex 21, is 21 pairs. [203]

6. [98]

   Mr Walton explained to the jury that DNA analysis involves extracting DNA from a sample taken from a suspect, crime scene, victim or location, measuring it, amplifying it by making many copies of the area of interest (known as the Polymerase Chain Reaction method; “PCR”) [204] and then subjecting it to an STR analysis. [205] A graphical representation of the digital results of the analysis can be presented in the form of an electropherogram (“EPG”) which, in the case of a simple sample concerning one person, illustrates the presence of two alleles at a particular locus by two peaks. Hence, a simplified example of part of an EPG for a DNA sample from one contributor is as follows: [206]

7. [99]

   This extract from an EPG depicts a DNA sample that a STR analysis shows as having an allele pair of “15,17” at one locus, “14,18” at another and “19,21” at a third. Mr Walton explained that an EPG for the locus, known as amelogenin (“AMEL”), shows the result for an allele that depicts gender. He explained that the y‑axis to this image measures “Relative Fluorescence Unit” (“RFU”) and can be considered “roughly equivalent to the amount of DNA that may have been present”. [207] Mr Walton described the small bumps in the above EPG as “various artefacts” which the interpreting scientists are “trained to try and identify”. [208] He explained that some are “technical artefacts, due to power fluctuations and things like that and some of them are due to the actual copying or testing process”, [209] which he described as a “stutter”. [210]

8. [100]

   Mr Walton explained that, if an EPG revealed more than two peaks at a particular locus, then that would confirm that there was more than one contributor to a sample. He explained that there would then be a determination of the minimum number of contributors, such that “if we have an area that has three or four peaks, then that indicates there’s at least two people there”, but it “could be three” as there may be common alleles between the contributors. [211] Mr Walton said that with mixtures it is possible to exclude a person as a contributor if their DNA profile (ie, combination of allele pairs) does not “match” the sample, in the sense of there being a correspondence with the peaks on an EPG. [212] If there is a correspondence between the profile contained in the sample of interest and a reference sample, it means that person “is not excluded”. In that circumstance, there are two explanations for the presence of the person’s DNA profile being: that it is either their DNA or, alternatively, it is a random match. [213] In that event, an assessment is made of “how likely a random person could match” that sample and that is made by reference to how “common it might be in the population”. [214] Mr Walton explained that this is undertaken by reference to a population frequency database, which is Australia‑wide and broken down into Caucasian, Asian and Aboriginal databases.

9. [101]

   As it is of relevance to the attack mounted on Dr Perlin’s evidence on appeal, Mr Walton’s evidence concerning the construction of the population database should be noted: [215]

10. [102]

    The reference to a “particular area” in this evidence is to a particular loci. Thus, Mr Walton explained that the population database is created by determining, from the “739 samples”, the frequency of a particular allele pair at a particular locus. He explained that this approach was “conservative”, in the sense of increasing the estimate of a random match, in two respects. First, because if a particular allele pair is not present in the sample it is nevertheless assumed to be present in 2% of the population. [216] Second, because this method treats the presence of a particular allele pair as independent of the presence of another pair, it therefore assumes an equal likelihood that “any person in the population could mate with any other person in the population”. [217] According to Mr Walton, experience shows that there is a greater tendency for people to marry within their racial and ethnic groups. [218]

11. [103]

    Mr Walton also said that the possibility of a random match in Australia was calculated by reference to three different populations, namely Caucasian (European/Middle Eastern), Asian and Aboriginal, [219] and “the lowest one, the most common one [is used] as the statistic for the general population”. [220]

12. [104]

    Mr Walton explained that the “preferred way of reporting” [221] was to use a “likelihood ratio” that compares two different hypotheses that explain the evidence. [222] Hence, with a single source a likelihood ratio will compare two hypotheses, namely, the probability that the evidence can be explained by a contribution from a particular victim (or offender) compared to the probability that “it comes from someone else who matches by chance”, with the result that “we can get a statistic to explain those two”. [223] With mixtures involving more than one contributor, Mr Walton stated that a likelihood ratio can be provided by comparing two hypotheses, for example the probability that the evidence is explained by DNA being contributed by person A and an unknown person, compared to two unknown persons. [224] However, such a ratio can only be provided if it is known (or assumed) “how many people [are] in a mixture”. [225]

13. [105]

    Mr Walton explained that, depending on how much DNA of each of the contributors is present, which is measured by the height of the various peaks on the EPG, the DNA sample is often separated into a “major” and “minor” component. [226] With some samples these components may themselves be a mixture of different DNA contributors. [227] Mr Walton explained that some DNA mixtures are too complicated for analysts to determine individual contributors, [228] although in cross‑examination he added that the minimum number of contributors can be determined. [229] Mr Walton foreshadowed Dr Perlin’s evidence by explaining that there are “computer programs that have been developed specifically for interpreting complex mixtures in DNA profiles”. [230]

Mr Walton’s Evidence on Stain 91

1. [106]

   On the second occasion that he gave evidence at the 2016 trial, Mr Walton told the jury that Stain 91 was subjected to each of the Y filer, Profiler Plus, Identifiler and PowerPlex 21 tests, although the latter could not be performed until it became available in 2013. [231] Of present relevance are the EPG results for the PowerPlex 21 which were displayed to the jury. [232] Mr Walton addressed the results at various loci. For the locus that determines gender, [233] the results showed two large peaks of slightly different height. Mr Walton explained that this meant that the results definitely included a male and, given that the other loci indicated multiple contributors, “there might be multiple males present”, [234] although the small height differential in the peaks “may indicate there is also a female individual present” [235] or “it could just be an imbalance from the testing”. [236]

2. [107]

   Mr Walton told the jury that the difference in the peaks on the results for Stain 91 allowed for a “differentiation of what we would call a major component and a minor component part”. [237] He said that, given the number of peaks at some locations, he “determined there was at least three individuals … in the major component” [238] and “at least one” in the minor component, [239] yielding a minimum of four contributors. [240] In relation to the major component, Mr Walton said that at least one of the contributors was male and most likely all were. However, he could not exclude a female contributor, [241] although “[if] there’s a female present, then it probably indicates it’s more likely to be in the minor component”. [242]

3. [108]

   Mr Walton said that each of Min, Henry and Terry Lin could not be excluded as one of the major contributors because all their genotypes (ie, pairs of alleles) were present in the major component. [243] He said that each of Lily Lin and Irene Lin could be excluded as major contributors, but could not be excluded as minor contributors. [244] He added that the sharing of allele pairs by the major contributors “can be indicative of related individuals”. [245] Mr Walton stated that, with one of the locus for Stain 91, the major component was all “consumed” with a peak for a STR of “11”, meaning that all of the contributors to the major component were “homozygous”, ie, of the same allele type. [246] Mr Walton said that the appellant, Kathy Lin and XX were excluded as contributors to the major component. [247] He said he could not exclude Kathy Lin and XX as contributors to the minor component, but contrasted their position with that of Lily and Irene Lin in relation to the minor component as follows: [248]

4. [109]

   Mr Walton then referred to the Y filer testing of Stain 91. With the major component, he stated that he could only identify one “Y profile” from the major component and it was the same Y profile that each of Min, Henry and Terry Lin shared. It was different to the appellant’s and XX’s Y profile. [249] In relation to the minor component, Mr Walton said that there was “no trace of a second Y” so that it was “probable that they are not in the mixture”, although that possibility could not be excluded. [250]

5. [110]

   As noted above, a Y filer test generates a profile referable to 16 loci on the Y chromosome. Mr Walton said that the Y profile in the major component of Stain 91 which matched Min, Henry and Terry Lin was compared to a database containing 2200 samples taken from NSW residents, one of which was Min Lin because his DNA was collected following a theft from his newsagency some years previous. [251] The only match was to Min Lin’s sample. Based on that Mr Walton stated: [252]

6. [111]

   Mr Walton also said that the Y profile was compared to an international database containing 30,300 Y profiles, which included “just over 5,000 Chinese profiles”, and yielded no matches. [253]

7. [112]

   Mr Walton concluded that the DNA mixture extracted from Stain 91 contained a minimum of four contributors (“definitely four” [254] ) and possibly more (“[f]ive, yes, or six or seven or – yeah, or more” [255] ). Mr Walton said he could not exclude Brenda Lin as either a contributor to the major component or minor component, [256] although if she was a contributor, it was more likely to the minor component than the major component given his conclusion that probably all three minimum contributors to the major component were males. [257] He undertook a so‑called “Random Man Not Excluded” calculation to determine how large a segment of the population was not excluded from contributing to Stain 91. [258] He determined that one in 730,000 members of the Australian Caucasian population and one in 210,000 members of the Australian South-East Asian population could not be excluded as a major contributor to the mixture. [259] He explained that, taking the latter figure, it was the “equivalent of saying out of every million people we would expect five to not be able to be excluded” from the DNA mixture in Stain 91. [260]

8. [113]

   The cross‑examination of Mr Walton did not seek to challenge any of the above conclusions but was instead directed to the validation studies of Dr Perlin’s TrueAllele system, and the potential for human bias to affect TrueAllele’s results. The evidence in relation to the validation of TrueAllele is addressed in detail below. In summary, Mr Walton explained that TrueAllele had been validated for “four contributors to a mixture and are trying to do five people” but the process was time consuming. [261] In relation to the potential for human bias, Mr Walton observed that the “computer program will analyse the sample without any bias”. [262]

9. [114]

   Mr Walton was also cross‑examined on the possibility that, in the swabbing of Stain 91, the forensic biologists may have collected DNA from outside the area of the stain [263] and the results for other stains. [264] He explained that with some very small peaks on an EPG an analyst will exercise a judgment to exclude that peak as representing a peak from a contributor and instead treat it as “static”. [265]

Dr Perlin’s Evidence

1. [115]

   During a break in Mr Walton’s evidence, and in the absence of the jury, it emerged that counsel for the appellant was raising an objection to the admissibility of Dr Perlin’s evidence. Whether that objection was ultimately pressed and its disposition is the subject of Ground 2 of the appeal. It is addressed below and rejected. Of present relevance is that, after Mr Walton had left the witness box for the second time and before Dr Perlin was called, counsel for the appellant agreed that it “must be accepted” that the DNA “of the three deceased males was … represented in [the] mixed profile”; [266] ie, it was accepted that the DNA mixture obtained from Stain 91 included the DNA of Min, Henry and Terry Lin. Counsel for the appellant advised that the real issue was whether Brenda Lin was also present and Irene and Lily Lin were not. [267]

2. [116]

   This concession is of particular significance to an assessment of the scope and content of the evidence that was led from Dr Perlin at the 2016 trial and the criticisms that are made of it on appeal, especially those that concern the potential presence of DNA from Min, Henry and Terry Lin in the DNA mixture obtained from Stain 91. In particular, these latter criticisms all concern attempts to reagitate a matter that was not in issue at the 2016 trial. The making of this concession by counsel for the appellant is one of the particulars of Ground 8 of the appeal. It is addressed below and also rejected.

3. [117]

   Amongst other academic qualifications, Dr Perlin has a PHD in mathematics, a PHD in computer science and a medical degree from the Prizker School of Medicine at the University of Chicago. His PHD in mathematics concerned probability theory and his PHD in computer science concerned artificial intelligence. [268] At the time Dr Perlin gave evidence at the 2016 trial, he was an adjunct Professor at Duquesne University in Pittsburgh, Pennsylvania and a member of the American Academy of Forensic Science, the American Society of Human Genetics and the American Statistical Association. [269] He has published extensively on the topic of statistics and DNA analysis. [270]

4. [118]

   Dr Perlin is the Chief Executive Officer and Chief Scientist of Cybergenetics, a company owned by him and his family, which predominantly undertakes forensic DNA analysis, although it also undertakes research in “genetics, cancer research and medical diagnostics”. [271]

5. [119]

   Dr Perlin told the jury that he had been involved in “400 cases to date” for either the prosecution, police forces, defence or “innocence projects”, predominantly in the USA, [272] but also in Canada, England and the Netherlands. [273] Of those 400 cases, 79 cases involved an examination of samples that had five or more contributors, being a total of 134 items. [274] A list of those cases was marked for identification. [275]

6. [120]

   Dr Perlin developed the TrueAllele software. He explained its operation to the jury at the 2016 trial. Dr Perlin stated that, with each of the 20 loci the subject of the Profiler Plus tests, there were approximately 100 potential allele pairs. Treating the areas as genetically independent meant that there are 10020 (or 1040) possible combinations of allele pairs or genotypes “which is a vast number of possible genotypes relative to the number of people [on] earth”, being 1010 (in fact less). [276]

7. [121]

   The first step undertaken by TrueAllele is to take the results of the DNA testing of the evidence sample provided, in this case Stain 91, and without considering any reference sample (eg Min, Henry or Terry Lin’s DNA), determine the probability that a particular contributor had a particular allele pair at a particular locus. [277] The result of this step is sometimes described as the “inferred genotype”. The nature of this inferred genotype and what was conveyed about it at first instance was the subject of debate on appeal. It suffices to state at this point that it is not a single set of 20 allele pairs, but instead a probability distribution of allele pairs, in that it attributes a probability to each possible allele pair that may be found at a particular locus. As we will explain, contrary to the appellant’s submissions, that matter was clearly conveyed by Dr Perlin to the jury and judges who sat at first instance.

8. [122]

   Dr Perlin explained to the jury the process of inferring the probability of a particular allele pair at a locus being a contributor to a mixed DNA sample. [278] He commenced with a simple example in which the jury was shown a slide depicting a sample EPG result for one locus showing a STR peak for each of 10, 11 and 12, with the peak for 12 twice the height of each of the peaks for 10 and 11. [279] On the assumption there were two contributors and one of the contributors had an allele pair of 10,12, then by a process of matching by trial and error, or in effect running simulations using the “Markov-chain Monte Carlo” method, [280] it could be inferred that the probability that the other contributor had an allele pair of 11,12 was 50%, the probability they had an allele pair of 11,11 was 30% and the probability they had an allele pair of 10,11 was 20%. [281]

9. [123]

   Dr Perlin’s explanation to the jury of the next steps in the process of “inferring” genotypes utilised three slides. The jury was first shown the following two slides which set out a portion of the EPG for Stain 91 at a particular locus known as “FGA”: [282]

10. [124]

    The figures 19, 21, 22, 24 and 25 represent the STR (ie, number of repeats) yielded by the sample at this locus. [285] The y‑axis measures the RFU of the relevant STR peak. As noted, it is in effect a measure of the quantity of the DNA mixture that has that STR score. [286] With the smaller peaks, Dr Perlin, referring to slide 7, explained that human analysts will apply a RFU threshold before they will regard such a peak as recording the presence of an allele with a particular STR. [287] Dr Perlin explained that the analysis undertaken by TrueAllele, indicated by slide 6, uses all the data, including very small peaks, “as potential events that come from alleles”, [288] although the size of the peak affects the probability attributed to its presence because it is considering the “degree” to which an allele is present. [289] Dr Perlin also stated that TrueAllele uses the pattern of highs and lows in the peak heights in inferring genotypes, as well as variations in the peaks. [290]

11. [125]

    Dr Perlin then explained the operation of TrueAllele by reference to the following slide:

12. [126]

    This slide is a graphical representation of one combination of allele pairs that are generated by TrueAllele to explain the results for the DNA mixture at locus FGA (ie, “inferred” allele pairs). Dr Perlin told the jury that in this example TrueAllele has been given an assumption of three contributors [292] and, as this combination of allele pairs has a result that is “very similar to the underlying data”, it “confers [a] higher probability to the different genotypes [on] this proposed pattern”. [293] This process of generating combinations of allele pairs also includes variations in the level of contribution from each such pair to the entire DNA sample, bearing in mind the RFU level for each STR score; eg, for the third person’s allele pair depicted in this slide “there may be a 10% contributor instead of a 50% contributor”. [294] However, the other possible allele combinations are not excluded by TrueAllele. Instead, the higher probabilities are attributed to the allele pairs noted above and all the other allele pair possibilities are assessed with relatively low possibilities. [295]

13. [127]

    Dr Perlin explained that this process is repeated as follows: [296]

14. [128]

    In this extract Dr Perlin referred to “100,000 other patterns”. He later explained that TrueAllele ran “100,000 or 200,000 different possibilities for each locus”. [297]

15. [129]

    A simplified example of the result of this process just for the locus “FGA” was then presented to the jury in the following slide:

16. [130]

    Dr Perlin explained that this simplified probability distribution for locus “FGA” concerned the first of the three assumed contributors for the DNA sample being considered. [299] Thus, for that contributor there would be a 35% probability that it would have an allele pair “19,21”. The probabilities in this slide total 99%. The remaining 1% is spread between all the other possible allele pair combinations that could occur at this locus. Dr Perlin told the jury that the “probability is concentrated largely” on the “three possible genotypes, the 19,21, the 19,24 and the 21,24” and the “other 95 or so possibilities have lower probabilities than these genotype possibilities”. [300]

17. [131]

    As it is of some significance to the complaints made on appeal, it is appropriate to note Dr Perlin’s explanation of the process undertaken by TrueAllele at this point: [301]

18. [132]

    The references to colours in this answer are to those set out in slide 8 (see [125]). The significance of this answer is that Dr Perlin is clearly describing that each inferred genotype for each assumed contributor that is created by TrueAllele is a set of probabilities of the presence of a particular allele pair at each locus; ie, a probability distribution. In his evidence on the voir dire before Johnson J, Dr Perlin explained that with “probabilistic genotyping … you end up with a probability distribution for each of the separated contributors” and not an “exact” or “definite genotype” which is not “needed to compute a match statistic”. [302]

19. [133]

    Having generated the probability distribution for each locus without regard to any reference sample, TrueAllele then compares that distribution to the DNA profile of the reference sample (eg, Min or Terry Lin) to generate a “match statistic”. This was explained to the jury using the following slide:

20. [134]

    The blue bars on the left of each pair in this chart represent the calculated probability that each allele pair formed part of the genotype of this inferred contributor to the analysed mixture. The brown bars on the right of each pair “represent the genotype of a random person … selected from the population” [304] and, in particular, the probability of that allele pair’s occurrence in the general population (or in this case the Australian Asian Population). [305] Dr Perlin explained that there would be about “100 of those [allele pairs], even though only four are shown”, representing all the possible allele pair combinations at that locus. [306] The circled pair of bars concerns the allele pair “19,24” which is the allele pair possessed by Terry Lin’s DNA at this locus; [307] ie, the allele pair at this locus of the reference sample. The figure of 2.5% represents the probability of the random occurrence of that allele pair in the Australian Asian Population (as derived from the Population or Frequency Database for the Australian Asian Population). [308]

21. [135]

    From these figures the “match statistic” is derived. Dr Perlin explained that “what the [math] lets us do, essentially, is ignore the other allele pairs and simply divide the probability of the genotype after we've seen the data, the probability of an evidence match, the blue bar height, by the chance of a coincidental match, the brown bar height”. [309] In the case of Terry Lin, at this locus this meant dividing 34% by 2.5% which the slide suggests is 13 (but is in fact 13.6). This is the match statistic for this locus. This process is then repeated at all 20 loci with the match statistics multiplied by one another.

22. [136]

    A total match statistic that exceeds one provides “inclusionary support” for the reference sample while a match statistic that is less than one provides “exclusionary support”. [310] The extent to which the total match statistic exceeds or is lower than one is a measure of the strength of that support. [311] Hence, a total match statistic of one in a million is relatively strong exclusionary and a match statistic of a million is relatively strong inclusionary. [312] In the above example, a match statistic for the allele pair “24,24” would produce a match statistic at that locus of less than 1 (as the right hand bar exceeds the left hand bar) which would tend to exclude someone with that allele pair. However, any overall assessment of that would be based on the match statistic derived from multiplying the statistic for all 20 allele pairs. [313] Dr Perlin stated that it was not uncommon to obtain different results for different loci. [314]

23. [137]

    At this point, it is appropriate to explain the underlying rationale for the comparison between the probability of occurrence of the reference samples’ allele pair in the relevant mixture and the probability of its occurrence in the general population. The heading to slide 10 asked “How much more does the victim match the evidence than a random person?” (see [133]). Before the jury Dr Perlin expanded on this as follows: [315]

24. [138]

    The first answer in the above extract clarifies that the match statistic involves a comparison between the “degree” of the match between, in this case, a victim’s DNA and the evidentiary sample, with the degree of a match with a random person. This answer is of particular significance because of the complaint made on appeal that Dr Perlin’s methodology was flawed because, inter alia, it ignores the existence of allele pairs with higher probabilities at a particular locus than the reference sample, such as “19,21” which had a 35% chance of contributing, compared to “19,24” which had a 34% chance of contributing to the DNA mixture. At this point it suffices to note that Dr Perlin clearly told the jury that the other allele pairs were ignored at this point of the analysis because the relevant comparison was between the probability of occurrence of the reference sample and the probability of occurrence of a random person.

25. [139]

    As stated by Dr Perlin, this reasoning deploys “Bayes' Theorem” which is a means of describing the probability of an event based on prior knowledge of conditions that might be related to the event. The theorem holds that the odds of a hypothesis given certain evidence (the “posterior odds”) equals the odds of the hypothesis without that evidence (the “prior odds”) multiplied by the ratio between the probability of that further evidence if the hypothesis is true and the probability of that further evidence if the hypothesis is not true (ie, the likelihood ratio) (see D Hodgson, “A Lawyer looks at Bayes Theorem” (2002) 76 ALJR 109 at 109 to 110; cited by Spigelman CJ in R v Galli [2001] NSWCCA 504; (2001) 127 A Crim R 493; “Galli” at [55]). The application of Bayes’ Theorem by juries to non‑statistical evidence or a combination of statistical and non-statistical evidence has been discussed but generally deprecated (Hodgson supra; R v Denis Adams [1996] 2 Cr App R 467; R v Denis Adams (No 2) [1998] 1 Cr App R 377).

26. [140]

    The underlying logic behind the application of Bayes’ Theorem by TrueAllele in this context can be illustrated by a simplified analogy based on an explanation that Dr Perlin provided in his evidence before this Court. [316] Assume that TrueAllele determines the probability that an inferred contributor to a DNA mixture had a particular allele pair is 30%, that that allele pair corresponded with a person having blonde hair and that a reference DNA sample of a victim also contained that allele pair. (Although generally nuclear DNA testing does not concern genes that affect a person’s appearance or other characteristics). According to Dr Perlin, that would not provide information about the likelihood that the victim’s DNA was present in the mixture unless it was also known what the incidence of that allele pair is in the relevant population. If, for example, all the relevant events and persons concerned the Scandinavian states, and assuming that the incidence of this allele pair resulting in blonde hair in the Scandinavian states was 60%, then the TrueAllele type analysis at this locus would yield a match statistic of ½ (30/100 divided by 60/100). Such a figure would tend to exclude that victim as a contributor to the sample (although any assessment of that would require a consideration of all allele pairs). On the other hand, if all the relevant events occurred somewhere else in the world where the incidence of this allele pair at this locus resulting in blonde hair was say, 3%, then that would yield a match statistic of 10 (30/100 divided by 3/100) and that circumstance would tend to support a conclusion that the victim was a contributor to the sample. In the Scandinavian states example, there is a lower chance that the inferred contributor has blonde hair compared to the general population and that circumstance tends to exclude a victim with blonde hair as having contributed to the sample. In terms of Bayes’ Theorem, the prior odds decrease by a factor of 2. In the other example, there is a higher chance that the inferred contributor has blonde hair compared to the general population and that circumstance tends to include a victim with blonde hair as having contributed to the sample. In terms of Bayes Theorem, the prior odds increase by a factor of 10.

27. [141]

    Dr Perlin explained that, as the first step in this process involves the running of hundreds of thousands of simulations, then it follows that a rerunning of TrueAllele will not produce an identical probability distribution even if the same number of contributors is assumed and the same number of simulations is performed. Instead, one should expect “to get a slightly different result”. [317] He said that where a number of runs are performed, he would report a “typical value”. [318] In this case, “computer runs [were undertaken] assuming three, four or five contributors”, but Dr Perlin chose to report “the consistent, or more conservative numbers that [were] found on the three assumed contributor runs”. [319] However, as indicated below, he gave evidence before the jury of results for four and five contributor runs as well in respect of each person.

28. [142]

    As noted, after being given an assumption about the number of contributors in a sample, TrueAllele then determines a DNA profile of each such contributor in the form of a probability distribution for each possible allele pair at each locus (the so called “inferred contributor”). In doing so, it also determines a percentage contribution that each such inferred contributor made to the DNA sample based on the heights of the various peaks on the EPG. Dr Perlin told the jury that “as the computer is determining the different variables that it’s solving for, one of those variables is the relative quantities of the amounts of DNA”. [320] Dr Perlin told the jury that there is a “strong correlation” between the calculated contribution percentage for an inferred contributor and the size of the match statistic. [321]

29. [143]

    The jury was then shown a slide that Dr Perlin explained set out the match statistic at each of the 20 loci for Terry Lin, assuming there were three contributors to the DNA found in Stain 91. [322] The jury was then shown the following slide which set out the match statistic for Terry Lin derived from multiplying those 20 match statistics: [323]

30. [144]

    The logarithmic equivalent to the first of these figures is 16.70 (ie, 1016.7). Dr Perlin told the jury that if four contributors were assumed then the result is “essentially the same”, being 16.86 (ie, 1016.86 compared to 1016.7). [324] Similarly, with five assumed contributors the match statistic was 1013.11. [325] Dr Perlin said that each of these figures was associated with what TrueAllele determined was the major component of the mixture, specifically 59% when three contributors were assumed, 55% when four contributors were assumed and 31% when five contributors were assumed. [326]

31. [145]

    Dr Perlin told the jury that, from his knowledge of the various validation studies that have been performed, the instances of “false positives” (ie, an inclusionary match statistic for someone whose DNA is not present [327] ) decrease as the match statistics increase. He said that once they “reach a match statistic of 1,000 or three zeros we rarely, if ever in the studies, will see a false positive match even if millions of comparisons are examined”. [328] He was then asked: [329]

32. [146]

    The second answer in this extract is the subject of criticism by the appellant and Professor Gill on the basis that it evinces the “prosecutor’s fallacy”. This criticism is addressed below. [330]

33. [147]

    In relation to Henry Lin, the jury was shown a slide similar to the one above which stated a “match between the garage floor and Henry Lin is … 2.21 billion times more probable than a coincidental match to an unrelated Asian person” (assuming three contributors). [331] He was then asked: [332]

34. [148]

    Again, these answers were criticised on the basis that they are said to involve the prosecutor’s fallacy. As explained below, Dr Perlin defended these answers on the basis that mathematically he was correct in attributing the maximum likelihood of seeing this match statistic for a person who was not in fact a contributor as being the inverse of the match statistic.

35. [149]

    Dr Perlin then provided the figures based on four assumed contributors. Dr Perlin referred to two “runs” of TrueAllele for four assumed contributors which produced match statistics for Henry Lin of 106.88 and 108.96 and a run of TrueAllele that assumed five contributors where the match statistics were “in the billions”. [333] In relation to the percentage contribution, Dr Perlin explained: [334]

36. [150]

    The jury was then shown a slide referable to Min Lin which stated that a “match between the garage floor and Min Lin is … 226 thousand times more probable than a coincidental match to an unrelated Asian person” (assuming three contributors). [335] Dr Perlin explained that one four contributor run of TrueAllele yielded a match statistic for Min Lin “at the level of” 108.72 , another four contributor run yielded a match statistic “in the, nine zeros” and a five contributor run yielded a “match statistic [that] had 11 zeros in it”, being 1011.43. [336] Dr Perlin explained that his contribution was assessed as 30% when three contributors were assumed, “around 30% out of four contributors ... and, when assuming five contributors for that separation, his percentage was 26%”. [337] Dr Perlin was asked: [338]

37. [151]

    The jury was then shown a slide stating that a “match between the garage floor and Yun Bin Lin [ie, Irene Lin] is … 28.5 thousand times more probable than a coincidental match to an unrelated Asian person” (assuming three contributors). [339] Dr Perlin said that with four assumed contributors the relevant match statistic was 104.37 and with five contributors it was 105.23. [340] In relation to whether she was present as a major or minor contributor, Dr Perlin stated that, with three assumed contributors, “she is present in a 7% component, along ‑ in a female fraction”, with the results “getting a better separation with four, in one result she was at 11%, another at 8%. And with five unknown contributors … she is present at 11%”. [341] It was put to Dr Perlin in cross‑examination that the result for Irene Lin was “miserably unreliable”, a proposition he rejected. [342]

38. [152]

    Bearing in mind the match statistics associated with Irene Lin, Dr Perlin was reminded of his earlier evidence of having seen “false positives”. He was then asked: [343]

39. [153]

    The jury was then show a slide referable to Lily Lin which stated that a “match between the garage floor and Yun Li Lin [ie, Lily Lin] is: 289 times more probable than a coincidental match to an unrelated Asian person” (assuming three contributors). [344] Dr Perlin told the jury that for four assumed contributors her match statistic was 104.45 on one run and 104.04 on the other and for five assumed contributors it was 103.58. [345] In relation to the level of her contribution, Dr Perlin explained that “she [was] following the same genotype as Irene in each case”, that is, a minor contributor. [346]

40. [154]

    When it came to expressing an opinion on the presence of Lily Lin’s DNA in the DNA taken from Stain 91, Dr Perlin was circumspect. He observed that “based on validation studies, it’s more probable that [her result] could be a false positive than with the higher statistics”. [347] In cross‑examination he agreed that he was “not able to say whether or not Lily is present”. [348]

41. [155]

    Dr Perlin also referred to a “notion … in family studies” which he called “shadowing”, [349] whereby an “individual is not present [in the DNA sample], but they are giving an apparently strong match statistic because of the close genetic relationship between the true contributor and the relative”. [350] He was asked as follows: [351]

42. [156]

    The emphasised answer in this passage was criticised by Professor Gill on the basis that it somehow displayed the prosecutor’s fallacy. This criticism is also addressed below. [352] At this point it suffices to observe that Dr Perlin’s answer about there being no possibility that neither woman’s DNA was in Stain 91 was given in the context of his having discussed documented error rates, provided the jury with match statistics for each of them, and then discussed the inter-relationship between the match statistics of Irene and Lily Lin and the possibility of shadowing between them.

43. [157]

    Dr Perlin expanded on the concept of “shadowing” stating: [353]

44. [158]

    As noted, one matter raised by the appellant as potentially defeating the incriminating effect of a conclusion that a stain containing DNA from multiple victims was found in his garage was the possibility that it also contained Brenda Lin’s DNA. Accordingly, Dr Perlin addressed TrueAllele’s assessment of the probability that Stain 91 contained DNA from her. The jury was shown a slide referable to an assumption of three contributors stating that a “match between the garage floor and Brenda Lin is: 69.3 more times more probable than a coincidental match to an unrelated Asian person”. [355]

45. [159]

    Dr Perlin was then asked: [356]

46. [160]

    Dr Perlin was asked whether shadowing explained the high match statistics for Min, Henry and Terry Lin. Dr Perlin said it did not, especially having regard to the results yielded for them by TrueAllele when five contributors were assumed. He said that by that stage “they are more nicely separated out”, that is, with five assumed contributors there is a better correspondence between each inferred contributor and each of Min, Henry and Terry Lin, rather than more than one of them having results that reflect a single inferred contributor. [357]

47. [161]

    The topic of shadowing in relation to Brenda Lin was taken up with Dr Perlin in cross‑examination as follows: [358]

48. [162]

    In re‑examination, Dr Perlin was again asked about shadowing and was asked about the results of a five contributor run as follows: [359]

49. [163]

    It is necessary to set out these passages because it relates to the issue raised at the trial on behalf of the appellant, namely the possible presence of Brenda Lin’s DNA in Stain 91, and was the subject of much debate on appeal. So far as the jury is concerned, the effect of Dr Perlin’s evidence was that for three contributors her match statistic was very low, for four contributors the match statistic was in the thousands or “tens of thousands” and was higher for five contributors, however Brenda Lin was shadowing her father and brothers. The bold answer (“yes”) in [159] was ambiguous as to whether Dr Perlin was also stating that, for some match statistics, Brenda Lin was shadowing her mother and aunt. The balance of his evidence refers to her shadowing her father, and especially her brothers, with whom she shares a significant number of allele pairs. In cross‑examination, Dr Perlin was pressed for his opinion as to whether Brenda Lin’s DNA was present in the mixture and gave it.

50. [164]

    At this point it is necessary to identify the source of the match statistic figures referred to by Dr Perlin as it assists in resolving the issues on appeal. During the voir dire before Johnson J in 2014, the table which is Annexure 1 to this judgment was attached to one of Dr Perlin’s reports and was the subject of cross‑examination. It sets out the match statistics obtained for each of the relevant TrueAllele runs that were undertaken with variations in the number of assumed contributors and the number of simulations undertaken in each run. It seems that Dr Perlin was referring to that document in his evidence set out at [159], (ie, “this table” and “I’m looking from the largest number here”).

51. [165]

    Of relevance to considering the above evidence are the following rows taken from Annexure 1:

52. [166]

    The second column in this table indicates which run of TrueAllele generated the results in the balance of the entries in the row. Thus, the first row concerns a run of TrueAllele based on an assumption of three contributors and using 100,000 simulations. The third column indicates which of the inferred contributors for each run the results in the balance of the row relate to. Hence, row 19 concerns the second inferred contributor. The fourth column indicates the number of assumed contributors for that run. Hence, that column for row 25 indicates that for that run five contributors were assumed. The weight column indicates the calculated percentage contribution of that inferred contributor. Thus, row 13 indicates that inferred contributor 4 was calculated to contribute 11% of the total amount of DNA derived from Stain 91. The next column is the standard deviation for the calculated weight contribution. The column headed KL is a reference to “Kalback-Leibler”. This refers to a statistic that, according to evidence given by Dr Perlin at the voir dire hearing, “measures to what extent one probability distribution diverges from another probability distribution”. [360] The balance of the rows indicate the logarithm of the match statistics calculated for each of the named persons for that inferred contributor for that run of TrueAllele. The blank entries indicate that the logarithm of the match statistic for that person was negative; ie, the match statistic was less than one and thus exclusionary.

53. [167]

    The match statistic for three contributors for Brenda Lin that was provided to the jury (ie, 69.3) was derived from row 4 of this table (ie, 101.84). The figure of 11% that Dr Perlin quoted as the calculated contribution to a four person sample in his evidence set out at [159] above was a reference to row 13. Dr Perlin’s reference to Brenda Lin’s match statistic of 3.16 for another four contributor run was taken from row 19. His reference to a match statistic of 4.91 for a five contributor run was taken from row 25. [361] In the above extract, Dr Perlin repeatedly referred to Brenda Lin shadowing her father and brothers which he illustrated by, inter alia, the entries for rows 1, 4 and 25 where Brenda Lin’s match statistic was always greatly exceeded by one or more of the match statistics for her father and brothers.

54. [168]

    In the extract from his re‑examination set out at [162], Dr Perlin referred to row 25 and the match statistics for Min, Henry and Terry Lin. [362] Dr Perlin told the jury that the “fact that ... a male component, that’s giving strong statistics to three males, indicates from those validation studies that … a [match] statistic to Brenda of 4.91, that’s in the order of 6 zeroes, or a million fold less, suggests that she is not there”. [363] With row 19, Brenda Lin’s match statistic was exceeded by each of Lily and Irene Lin’s match statistic. [364] In cross‑examination at the 2016 trial, Dr Perlin was taken to row 18 which contains match statistics for Brenda Lin of 3.69 and 7.05, 3.39 and 5.01 for Min, Henry and Terry Lin respectively. Dr Perlin described that as Brenda Lin shadowing her three male relatives. [365]

55. [169]

    Dr Perlin told the jury that there was “no statistical support for a match” between the appellant and the contributors to the DNA in Stain 91. [366]

56. [170]

    Dr Perlin told the jury that “[w]hen we initially look[ed] at the data and examin[ed] it under the assumption that people were not related, it looks like there’s three people present”. [367] However, once it was recognised that they are relatives who share alleles “we went on and tested, assuming four contributors, [and] assuming five contributors”. [368] His opinion on how many contributors were present was “at least four people” and “possibly five”. [369] Dr Perlin stated that if there is allele sharing between contributors then “[y]ou may end up with lower match statistics than you might otherwise”. [370]

57. [171]

    Dr Perlin stated that he did not make the source code of TrueAllele publicly available, describing it as a “trade secret”. [371] He said it would take one person approximately eight and a half years to read it all. [372] In any event, Dr Perlin said that the mathematical function of TrueAllele had been expanded on in various published papers and that systems such as TrueAllele can be validated “by testing the executable software … on real data … by testing technology on actual inputs, not by reading source code”. [373]

58. [172]

    Dr Perlin described two types of validation tests, one by the manufacturer and one by an individual laboratory that adopts it. [374] Consistent with Mr Walton’s evidence, he said that in NSW, TrueAllele had been validated for mixtures involving four contributors and was in the process of being validated for five contributors. [375] He identified six laboratories in the USA that had validated TrueAllele for five contributors or more. [376]

59. [173]

    Dr Perlin also told the jury that a Master’s student at Duquense University had conducted a study of TrueAllele using two, three, four and five person mixtures from the same family and it had produced inclusionary match statistics (although he could not recall whether “all five were pulled out”). [377] In cross‑examination, he said he facilitated that student’s use of TrueAllele and was a member of her “Thesis committee”, but she was supervised by another faculty member. [378]

60. [174]

    In cross‑examination it was suggested that TrueAllele was not appropriately validated: [379]

61. [175]

    In re‑examination, Dr Perlin was taken to a list of 33 validation studies of TrueAllele that were published in the period from 2004 to October 2016. [380] Dr Perlin nominated various papers in the list which he stated support his answers about the validation of TrueAllele. The list was marked for identification. [381] A revised version of the document which delineated between the various topics and nominated studies that were independent of TrueAllele was later tendered without objection as Exhibit GD. [382] It will be necessary to return to some of the papers listed in Exhibit GD later, but at this point it suffices to note that Exhibit GD lists the papers as addressing various topics, namely, “[d]egradation where 3 or more contributors assumed” (six papers), “[a]llele drop out” (five papers), “[a]llele overlap with three or more contributors” (10 papers), “[m]ixed contributors with more than three contributors and up to five contributors where kinship specifically addressed” (4 papers) and “[p]apers referred to in the Report to the President nominated by Dr Perlin as inconsistent with the findings of the report” (2 papers). [383]

62. [176]

    It was suggested to Dr Perlin in cross‑examination that TrueAllele’s match statistics were affected by degradation of the DNA. Dr Perlin agreed that a comparison of the results of the Profiler Plus test undertaken in 2010 and the PowerPlex 21 test in 2013 suggested that there had been some degradation in the data, but nevertheless the data was “of sufficient quality to render a good interpretation”. [384] He said that TrueAllele takes account of degradation as it models the variation in the peak heights at each locus. [385] Dr Perlin told the jury that he did not see evidence of any “significant differential degradation”, that is, degradation of a particular contributor. [386] He was also cross‑examined on the “President’s Report” referred to above. [387]

Further Evidence from Mr Walton

1. [177]

   The Crown recalled Mr Walton to address three issues that arose during Dr Perlin’s evidence. First, he discussed the quantity of DNA that was available to be tested. [388] Mr Walton stated that “[w]e obtained a strong profile”. [389] Second, he described the process by which DNA strands degrade over time, being that “as cells die” the DNA strands “break down into shorter fragments”, [390] and “differential degradation” is where the DNA contributions to a mixture degrade at different rates. [391] With this sample, Mr Walton said that it was affected by “inhibition”, being the effect of the chemicals used in the extraction process on DNA testing, [392] and “probably degradation … as well”, [393] but they could not determine whether there was differential degradation. [394] Third, Mr Walton confirmed that when DAL validated TrueAllele for DNA mixtures involving three and four contributors, the testing included mixtures where the minor component was less than 20% and in some cases less than 10%. [395] In cross‑examination, he said that the validation process included testing of contributors who were related and comparisons to persons who were not contributors but were related to contributors. [396]

The Addresses

1. [178]

   In her address, the Crown Prosecutor summarised Mr Walton and Dr Perlin’s evidence. [397] The Crown Prosecutor reminded the jury of the match statistics provided by Dr Perlin for Min, Henry and Terry Lin and submitted that they were always present in “what had been inferred, or separated out as a major component”. [398] The Crown Prosecutor submitted that Dr Perlin’s evidence was consistent with Mr Walton’s evidence, in that Mr Walton said that there was a minimum of three contributors in the major component, that they were all likely to be males and “there was only one Y profile that matched Henry, Terry and Min”. [399] The Crown Prosecutor then addressed Irene and Lily Lin’s match statistics and submitted that the jury “would be satisfied that Irene is in the mixture as the minor contributor” [400] along with Min, Henry, Terry Lin and “a possibility of Lily”. [401]

2. [179]

   As for the presence of Brenda Lin’s DNA in the mixture taken from Stain 91, the Crown Prosecutor submitted: [402]

3. [180]

   The Crown Prosecutor then addressed various arguments she anticipated would be raised in the address by the appellant’s counsel, including the effect of the validation studies. [403] The Crown Prosecutor submitted that, even in the absence of a conclusive test for the presence of blood, the jury should conclude that Stain 91 was a blood stain with a “mixture of four of the deceased”. [404] The Crown Prosecutor submitted that all of the suggested explanations for their DNA being present in the one sample, including from use of a treadmill in the garage, should be rejected, especially in the absence of evidence that Min Lin entered the garage at the Beck Street home. [405] Ultimately, the Crown Prosecutor submitted that the “real explanation for Stain 91 is that it is a mixture of the blood of the four deceased that … [was] brought back by the accused on the night of the murders on some item which then … [was transferred] … from the item on to the garage floor”. [406]

4. [181]

   In his closing address concerning Stain 91, counsel for the appellant accepted that Min, Henry and Terry Lin “are in the mixture”. [407] However, he went on to remind the jury of the match statistics for Brenda Lin on the assumption that there were four or five contributors [408] and submitted that there “is a strong possibility and, or a probability, … that Brenda is in item 550 [ie, Stain 91]”. [409] He submitted that if Brenda Lin was a contributor then it would support the contention that Stain 91 was not a blood stain and that the DNA within the stain was the product of “DNA transfer consistent with innocent explanation”. [410] Later in his address, counsel invited the jury to reject Dr Perlin’s evidence that the match statistics for Brenda Lin were indicative of her “shadowing” her relatives. [411] He reminded the jury of the President’s Report. [412] He also referred to the absence of any match statistics for Kathy Lin who could be expected to share alleles with her brother Min Lin, [413] Mr Walton’s evidence that he could not exclude Brenda Lin as a major contributor [414] and the potential for allele drop out and stutter in the process of converting DNA to an EPG. [415] He submitted that Dr Perlin’s evidence excluding Brenda Lin as a contributor based on shadowing of relatives with higher match statistics was simply an exercise in human judgment [416] and referred to the extract from his cross‑examination of Dr Perlin on the topic of shadowing set out above. [417] He submitted that there was inadequate validation of TrueAllele for mixtures of related persons [418] and there was the potential for degradation of the DNA samples. [419]

Trial Judge’s Summing Up

1. [182]

   As is to be expected, the trial judge’s summing up in relation to Dr Perlin was mainly directed to the factual issue between the parties about the possibility that Brenda Lin was a contributor to the DNA obtained from Stain 91 and Dr Perlin’s opinion about shadowing. In light of the issues raised on appeal it is only necessary to note the following part of the summing up:

2. [183]

   The trial judge then reminded the jury of the questions and answers of Dr Perlin in cross‑examination and re‑examination concerning the presence of Brenda Lin’s DNA, before telling the jury:

3. [184]

   The trial judge then reminded the jury of a number of the arguments put by the appellant’s counsel before moving to another topic. [420]

4. [185]

   Just prior to the trial judge delivering this part of the summing up there was an extensive discussion between the trial judge, the Crown Prosecutor and counsel for the appellant about Mr Walton’s evidence and whether he supported the concept of “shadowing”. [421] There was no application for a redirection in relation to any of that part of the summing up set out above.

PART 5: Criticisms of the DNA Evidence on Appeal

1. [186]

   As noted, on appeal the appellant sought to mount an attack on TrueAllele’s results as well as Dr Perlin’s evidence that was far wider than raised at the 2016 trial and the voir dire before Johnson J. The various complaints were littered throughout the appellant’s lengthy written submissions and restated in the specific complaints made under each ground. The Crown addressed these complaints in turn before replying to the particular complaints made under each ground of appeal.

2. [187]

   We will address the contentions in the manner addressed by the parties. However, one difficulty in doing so is that there is different evidence relevant to the appellant’s complaints depending on whether they are considered by reference to the position at the time of the voir dire, at the time of the 2016 trial or at the time of appeal. This difficulty is compounded when it is borne in mind that the issues between the parties (and the threshold for admission) at each stage were different. At the risk of stating the obvious, the issue before Johnson J on the voir dire was the admissibility of Dr Perlin’s evidence and the results of TrueAllele and the issue at the 2016 trial was the presence or absence of Brenda Lin’s DNA in Stain 91. The issue sought to be raised in this Court was, in general terms, whether there was a miscarriage of justice occasioned by the alleged unreliability of the TrueAllele results or the supposed lack of qualifications on the part of Dr Perlin to express certain opinions.

Superior Matching Genotypes Allegedly Ignored

1. [188]

   One of the principal contentions on appeal was that the match statistics produced by TrueAllele were effectively meaningless because there were a vast number of genotypes that could be generated which would produce a higher match statistic for Stain 91 than any of the victims. [422] In summary, this issue was floated but not pursued in the voir dire before Johnson J and not raised at any of the trials. This contention was not supported by any evidence led either at the 2016 trial or on appeal. The evidence of Professor Gill on appeal did not address this complaint. The evidence on the voir dire and led at the trial was to the contrary. Dr Perlin’s uncontradicted evidence on appeal is that the proposition is misconceived. In particular, it ignores the statistical logic that is the basis of the modelling undertaken by TrueAllele and the evidence concerning the match statistic for a reference sample against match statistics that are representative of the general population (ie, “specificity plots”).

2. [189]

   To explain these conclusions, the starting point is to note that, as Dr Perlin explained to the jury at the 2016 trial, given that 20 loci are being considered and there are approximately 100 allele pair combinations at each locus, it follows that there are in the order of 1040 possible genotypes (ie, sets of allele pairs) that can be hypothetically constructed. [423] However, there are only in the order of 8 billion people on Earth, ie, around 109.9. Thus, there are in excess of 1039 hypothetical sets of allele pairs that do not correspond to an actual person.

3. [190]

   The appellant’s contention is best approached by considering its genesis, being parts of a “case packet” that was tendered on the voir dire before Johnson J and subsequently updated. [424] This material included documents that provided three sets of figures for a particular inferred contributor derived from a run of TrueAllele that assumed three contributors. These figures were described in the case packet material as the “[c]omputer-inferred contributor genotypes … at every locus”, the “reference genotypes used in the case” and the “allele frequency data used for population databases”. [425] The second and third sets of data correspond to what is described at [133] to [134]. The first set of data is a probability distribution of the occurrence of each possible allele pair at each locus for the relevant contributor, with the probabilities totalling 99%. [426]

4. [191]

   The appellant’s analysis took the first set of data and compared the probability distributions for an inferred contributor to the actual genotype (ie, the sets of allele pairs) for the reference samples (ie, each suggested victim and where appropriate, Brenda Lin). The appellant noted that at each locus there are often other allele pairs with higher probabilities attached than the corresponding allele pair of the reference sample. The appellant submitted that this necessarily meant that there are a very large number of possible genotypes (ie, sets of allele pairs) that “better explain” the data than any of the victims. [427] This was said to be demonstrative of the “uncertainty” in Dr Perlin’s data.

5. [192]

   This contention is entirely directed towards the first step undertaken by TrueAllele in determining a match statistic, that is, the ascertainment of its numerator. It ignores the significance of the denominator, being the probability of occurrence of the reference genotype in the actual populations. As this complaint was not agitated at the 2016 trial, it is necessary to refer to part of the evidence given at the 2015 trial where Dr Perlin was shown slide 9 and asked about the 66% probability of the inferred genotype not being “19,24”. [428] Dr Perlin reiterated that probability was “irrelevant” because the likelihood ratio “focuses on the comparison between the evidence and the particular individual or other evidence relative to random”, such that “[w]hat is happening in other allele pairs is not relevant at all to the match statistic”. [429] The statistical logic of this approach has been explained above (at [137] to [140]). It is completely consistent with what Dr Perlin told the jury at the 2016 trial when explaining slides 9 and 10, namely, that the allele pairs that do not correspond to those in the reference sample are “ignore[d]” (at [135]). On appeal, the appellant did not attempt to address that underlying logic or adduce any evidence to suggest it was flawed. It was simply asserted that that is so. This is not sufficient.

6. [193]

   Prior to the hearing of the appeal, a series of questions were posed by the appellant for Dr Perlin to address. Many of those concerned the existence and number of those hypothetical genotypes. Dr Perlin’s written and oral response was emphatic and consistent. He freely accepted there were a large number of such theoretical genotypes but repeatedly stated that they were completely irrelevant. [430] Thus, in his written report he addressed numerous questions concerning the probability of the occurrence of the various victims’ genotype profiles (ie, sets of allele pairs) in respect of a particular inferred contributor’s probability distribution. For example, in relation to a particular three contributor run he was asked “[c]an the probability (as assessed by … TrueAllele …) that the full genetic profile of this separated out major contributor of 3 (on this run) is the same as Terry Lin's full genetic profile, as distinct from a different full genetic profile, be calculated by multiplying the probabilities for his genotype at each locus?” [431] Dr Perlin agreed that it could, but stated that it would only provide the numerator of the likelihood ratio. He said that numerator was 3.1978 x 10-8. However, when it came to the denominator the “the probability of this genotype occurring by chance is 6.3424 x 10-25” and “[t]herefore, the ratio of these two numbers is the likelihood ratio (LR), which is 50.4 quadrillion (log(LR) = 16.7026)” which is the relevant match statistic. [432]

7. [194]

   Various iterations of this “complaint” are to be found throughout the appellant’s written submissions. They are exemplified by the following contention: [433]

8. [195]

   The reference to “pages 11-25 of Annexure 1” in this extract is to the case packet material described above that was annexed to the appellant’s submissions. Two particular aspects of this submission, including the suggestion of a “misunderstanding” on the part of the trial judge, should be addressed.

9. [196]

   First, contrary to the foundation of this submission, there was “evidence as to whether those full [theoretical] genotypes, in excess of a million, correspond[ed] with real people”. Included in the case packet was a “locus table” showing the match statistic for each locus for a specific reference sample and the overall match statistic for that sample. [434] There was included a “specificity” plot, an example of which is as follows: [435]

10. [197]

    In his evidence on the voir dire before Johnson J, Dr Perlin explained that this is a “frequency chart or a histogram of what the distribution is of comparing this reported evidence genotype as a probabilistic genotype against 10,000 random non‑contributors”. [436] He said that it showed that “… it is extremely unlikely that there would be a false positive, that the distribution of individuals who do not contribute their DNA is shown in the blue bar, and compared to that, individuals who are far right of that distribution, are extremely unlikely to have been associated with this genotype mixture item by chance”. [437]

11. [198]

    During the voir dire, then Senior Counsel appearing for the appellant touched upon the issue now sought to be agitated on appeal with Dr Perlin. Dr Perlin was asked: [438]

12. [199]

    In re‑examination on this answer, Dr Perlin explained that: [439]

13. [200]

    Again, during the voir dire, former Senior Counsel for the appellant also raised in the cross‑examination of Ms Sharone Neville, the issue of other possible genotypes (that is, a set of allele pairs) that could produce a higher match statistic than the reference sample. Ms Neville is a forensic biologist and was then the manager of the DNA laboratory at FASS. [440] She participated in the local validation studies of TrueAllele. Ms Neville was asked: [441]

14. [201]

    The effect of this evidence is that the likelihood of there being another actual person’s genotype, as opposed to a hypothetical genotype, that might produce a higher match statistic is addressed by the comparison to 10,000 random profiles generated from the population databases, the results of which are set out in the specificity plots.

15. [202]

    This is consistent with Mr Walton’s explanation for the creation of those population databases as set out above. [442] He described the use of frequency types developed from 739 samples to “extrapolate ... out to the entire population”.

16. [203]

    For the sake of completeness, we note that a number of the papers concerning the validation studies that were tendered before Johnson J indicated that 10,000 random samples (or less) was a sufficiently large sample to test for specificity. [443] Ultimately, whether the use of 10,000 random profiles generated from such samples is sufficient for this purpose is a matter for expert opinion, although that would most likely involve a statistical assessment that did not require much sophistication. In any event, at the very least both Dr Perlin and Ms Neville considered it sufficient. The appellant, who had expert assistance available to him, did not call evidence to the contrary at any of the trials.

17. [204]

    The same position applies on appeal. In his oral evidence on appeal, Dr Perlin reiterated that the construction of population databases based on sample sizes of “100, 200 in Australia it might be 500” persons was sufficient. [444] In his written report he provided an updated and more sophisticated version of the specificity plots referred to above, which he described as a “non‑contributor analysis” and a “contributor analysis”. [445] His contributor analysis determined that the probability of occurrence of the theoretical genotypes with higher match statistics than Henry Lin was 1 in 13.7 trillion [446] and for Min Lin was 1 in 4.21 billion. [447] On appeal, the appellant again did not call evidence to contradict Dr Perlin or otherwise support the contention noted in [188].

18. [205]

    Second, the submission extracted at [194] above suggests that the case packet material reveals “a fundamentally different understanding to what an inferred separated genotype is, … against the [alleged] misunderstanding of the [trial judge]”. The asserted “misunderstanding” of the trial judge is identified in the written submissions as being that her Honour had supposedly “understood that full genotypes separately and objectively inferred, had been produced by the TrueAllele analysis, and these corresponded with the same full genotypes of the deceased”. [448]

19. [206]

    This contention is said to be supported by passages from the summing up in which her Honour gave the jury a general summary of Dr Perlin’s evidence and the methodology adopted by TrueAllele. The relevant description that her Honour gave to the jury of the process of inferring genotypes by TrueAllele was that “the programme … operate[s] upon ... an assumed number of contributors, a number which is pre‑set into the programme in order for the work the computer has to do in separating out possible genotypes, that is separating out an assumed number of genotypes”. [449] With respect, this is a completely unobjectionable description of TrueAllele. That is especially so having regard to the narrow issues before the trial judge at the 2016 trial concerning Dr Perlin’s evidence which principally concerned the possible presence of Brenda Lin’s DNA in the DNA mixture obtained from Stain 91. By the time of the 2016 trial any dispute over the validity of the general methodology of TrueAllele in producing a match statistic was in the distant past. The appellant conceded that the DNA of Min, Henry and Terry Lin were present in the DNA mixture extracted from Stain 91.

20. [207]

    Otherwise, the above passage from the appellant’s written submissions is implicitly critical of the trial judge for not reviewing the case packet data when an issue about the admissibility of Dr Perlin’s evidence arose at the 2016 trial (“but not clearly in fact reviewed”). The agitation of the admissibility of Dr Perlin’s evidence at the 2016 trial is the subject of Ground 2 and addressed below. When that issue arose her Honour did review the evidence adduced on the voir dire in the context of the issue raised by the appellant’s then counsel which did not include this complaint. The suggestion that the trial judge was obliged to review the case packet data tendered on the voir dire before Johnson J to ascertain what the appellant now contends they demonstrate is completely untenable, especially once it is accepted, as we do, that this criticism is entirely misconceived.

21. [208]

    One related complaint concerning this ground is that, in his evidence before the jury, Dr Perlin did not expressly state that there were multiple (theoretical) other multi‑locus genotypes which would be afforded positive match statistics greater than either those achieved by the reference samples or otherwise above 10,000. To that end, the submission set out above implies that something of great relevance was discovered by scrutinising the case packet material that was not revealed at the trial. This contention was expressly made elsewhere in the applicant’s outline of submissions provided at the appeal. [450]

22. [209]

    One difficulty with this contention is that it did not identify any particular question posed at the 2016 trial in response to which Dr Perlin was supposed to make this declaration. In any event, it is untenable. Dr Perlin was asked about this in his evidence before this Court. [451] He agreed that he did not expressly tell the jury at the 2016 trial that there were numerous theoretical genotypes that could be constructed and result in a higher match statistic than those concerning the victims. However, he added that was “pretty clear on the tables that we provided of the genotype probabilities that you could construct one if you wanted to” [452] and that, as noted, he did not regard it as relevant other than for the purpose of calculating error rates. [453] It follows from the above that we accept the contention that it was not relevant. Further, Dr Perlin made it clear to the jury that they are irrelevant when he told the jury, in relation to slide 9, that in calculating the match statistic the probabilities for allele pairs that are found in the reference sample are ignored. [454]

23. [210]

    In any event, it was readily apparent from the evidence adduced at the 2016 trial that theoretical genotypes with higher match statistics than the victims could be constructed. A moment’s reflection on slides 9 and 10 would reveal that at locus FGA there was an allele pair (“19,21”) with a higher probability (35%) than the allele pair (“19,24”) of the reference sample (34%). [455] A genotype with the allele pair “19,21” at this locus, but which had the same allele pairs as the reference sample at all other loci, would necessarily have a higher match statistic than the reference sample. However, any further reflection would have been a waste of time if one was also following the evidence of Dr Perlin to the effect that the relevant comparison was between the probability of the occurrence of the genotype of the reference sample in the probability distribution of the inferred genotype and the probability of the occurrence of that genotype in the general population. His evidence that this was the relevant comparison was consistent both at first instance and on appeal. It was uncontradicted and, to the extent necessary, we accept it.

Small Probabilities at an Individual Locus and Unreliable Results for Small Contributions

1. [211]

   The appellant also contended that somehow the reliability or probative value of the match statistics is undermined because, even though high match statistics were achieved for a particular victim, in some runs their allele pairs at a particular locus were not the most probable and in fact had a very low probability compared to other allele pair combinations at that locus. [456] This was said to be the case with the match statistics for Irene Lin where she was said to be “generally fairly low down the list of probability choices”, that is, for a particular inferred contributor’s probability distribution at a particular locus, Irene Lin’s allele pair was afforded a very low probability. [457] In fact, with some inferred contributor probability distributions a match statistic for Irene and Lily Lin was only calculated when the list of allele pairs at each locus was expanded so their respective probabilities cumulated to 99.99% as opposed to 99%. [458]

2. [212]

   This contention is simply another iteration of the complaint that has just been addressed. It focuses on the numerator of the match statistic without regard to the denominator and does not address the statistical logic that Dr Perlin explained lay behind the calculation of match statistics. [459] As noted, the methodology accepts that the numerator at an individual locus for a particular reference sample may be very low. However, the overall conclusion one draws from that depends upon the denominator at that locus, that is, the percentage occurrence of that allele pair in the population and the outcome of multiplying all of the match statistics derived for each locus. This was explained to the jury (and reiterated in Dr Perlin’s evidence on appeal). [460] Slides 9 and 10 made it clear to the jury that the allele pair of the reference sample may not be the most probable at an individual location.

3. [213]

   A related complaint to this concerns match statistics referable to inferred contributors with small inferred contributions by weight. The appellant’s submissions (correctly) noted that “there is less information (and so less certainty) where an [inferred] minor contributor is less than 10%”. [461] The written submissions then contended this involves a “problem” that is unspecified but which is said to be demonstrated by considering the match statistics in row 8 of Annexure 1, which show a match statistic for Irene and Lily Lin of 4.45 and 2.46 respectively. [462] This does not reveal any “problem”. A review of Annexure 1 reveals that with smaller inferred contributions there were generally much smaller inclusionary match statistics compared to large inferred contributors (eg, row 34 compared to row 33). Dr Perlin told the jury at the 2016 trial “[t]here is a direct relationship between the weight, as you say, or the quantity of DNA of a contributor, and the match statistic”. [463] Put another way, the lower match statistic quantifies the greater uncertainty that flows from the lower level of contribution. As Ms Neville said in her evidence on the voir dire, TrueAllele is “performing well when [it] assigns uncertainty that reflects the data”. [464] To a similar effect, the various validation studies reinforced that the match statistic was reflective of the complexity of the data. [465] For example, one such study with TrueAllele observed that “[i]f the data [is] uninformative, that fact is reflected in a diffuse genotype distribution and a low LR score”. [466]

Multiple Match Statistics for Inferred Genotypes and “Separation”

1. [214]

   The appellant contended that the unreliability of the match statistics produced by TrueAllele is demonstrated by the fact that its results for a single assumed contributor on a particular run produced inclusionary statistics for multiple persons. [467] A related complaint about Dr Perlin’s evidence was that he reported high match statistics to the jury for various victims that were referable to the same inferred contributor produced by TrueAllele on a particular run. Thus, for example, row 6 in Annexure 1 concerns contributor 3 and yields very high inclusionary statistics for each of Min, Henry and Terry Lin. The appellant noted that this row was the source of the match statistics that Dr Perlin provided to the jury for both Terry and Henry Lin on the assumption of three contributors. [468] The appellant’s submissions contended, or at least assumed, that one of those results must be a false positive and submitted that this was inconsistent with Dr Perlin’s evidence that match statistics above 10,000 do not produce false positives. [469] It was also contended that this phenomenon was inconsistent with evidence given by Dr Perlin on the voir dire before Johnson J when he stated that if “you make a positive identification, then, if everything is working well, then what you would expect is that the other contributors would be giving negative numbers”. [470] A further iteration on this complaint was the circumstance where the one reference sample produced inclusionary match statistics for different inferred contributors for the same run of TrueAllele. [471] For example, rows 19 to 22 of Annexure 1 reveal inclusionary match statistics for Min Lin for all four inferred contributors for a run that assumed four contributors and involved 200,000 simulations. [472]

2. [215]

   None of these complaints were agitated at any of the trials or on the voir dire before Johnson J. So far as the 2016 trial is concerned, this is not surprising. The factual foundation for this submission is the table of match statistics in Annexure 1. It was that table which was the basis for the match statistics that Dr Perlin informed the jury of, and that table appears to have been the basis on which counsel for the appellant cross‑examined Dr Perlin at the trial. As noted, at the 2016 trial it was accepted that the DNA mixture derived from Stain 91 contained DNA from Min, Terry and Henry Lin. The principal defence contention was that it also contained DNA from Brenda Lin. To support that contention the defence relied on various match statistics for Brenda Lin, especially the figure of 4.91 in row 25. That row contains higher match statistics for her other male relatives, the phenomenon now complained of. It would not have assisted this aspect of the defence case at the 2016 trial to contend that multiple inclusionary match statistics for the same inferred contributor was itself problematic.

3. [216]

   Even though the current complaint was not raised at first instance, the material that was adduced addresses it. That evidence was effectively restated by Dr Perlin in his evidence on the appeal. In summary, the occurrence of multiple match statistics for a single inferred contributor can be expected given that an inferred contributor is only a probability distribution not a single genotype (or single set of allele pairs). Such results are possible, even likely, when the number of assumed contributors is less than the number of actual contributors or where there is allele sharing between related contributors (or both). A better but not necessarily complete “separation” of match statistics can be achieved by re-running TrueAllele with more assumed contributors. In turn, this will enable an assessment to be undertaken about whether the occurrence of multiple match statistics for a single inferred contributor is the result of “shadowing” or allele sharing.

Evidence at First Instance

1. [217]

   In considering this issue, it is important to note the point made earlier that the inferred genotype for an assumed contributor produced by TrueAllele is a probability distribution that assigns probabilities to all the possible allele pairs at each locus. It does not identify a single set of allele pairs for that contributor. The appellant’s written submissions suggested that the jury was told to the contrary. The submissions noted (correctly) that the phrase “genotype” is “used frequently to describe a pair of alleles at a locus”. The submissions then contend that “[s]lides 9 and 10 ... were provided to the jury, showing one relevant inferred genotype (meaning pair of alleles at a locus)” and “[t]he jury [were] told that slide 9 shows the inferred genotype for the major contributor, with the programme run to assume 3, at the locus called 'FGA'”. [473] Slide 9 is set out above. [474] Self‑evidently, it does not show “one relevant inferred genotype” in the sense of “a [single] pair of alleles” at that locus. To the contrary, it shows part of a probability distribution for an inferred genotype, namely, the possible sets of allele pairs for that contributor at that locus with their associated probabilities totalling 99% with all of the other possible sets of allele pairs subsumed into the remaining 1%. As already noted, Dr Perlin explained this to the jury at the 2016 trial. [475]

2. [218]

   Once it is understood that an inferred genotype is a probability distribution then it follows that there is nothing inherently problematic in inclusionary match statistics being produced for multiple reference samples for the same inferred contributor (or one reference sample producing multiple inclusionary statistics for different inferred contributors). The more pertinent question is what that means in terms of likelihoods. The answer suggested by the evidence led at first instance is that the uncertainty that such a result suggests is captured by the calculation of the match statistic, although care is required in interpreting and reporting on those statistics especially when related reference samples are used and that otherwise it can be addressed by assuming more contributors to see if a “better separation” can achieved.

3. [219]

   In his evidence on the voir dire, Dr Perlin was asked if the result of using Brenda Lin as a reference sample was that she yielded a higher match statistic than Irene or Lily Lin then “it would be appropriate to replace one of the other two women in the [Stain 91] mixture”. [476] He responded:

4. [220]

   Further, Dr Perlin made it clear to the jury at the 2016 trial that more than one large inclusionary statistic could be derived from an inferred contributor’s probability distribution: [477]

5. [221]

   The first emphasised part of this answer is a reference to the sixth row of Annexure 1 which contains high inclusionary statistics for both Henry and Terry Lin for the one inferred contributor. In this passage, Dr Perlin clearly stated that both Henry and Terry Lin are “in” the same inferred contributor, ie, they both produce higher inclusionary statistics for that contributor. This answer also refers to the concept of “separation” which Dr Perlin discussed in detail before the jury. [478] The separation being discussed was the process of assuming more contributors and considering whether that led to inclusionary match statistics for the reference samples that did not also yield inclusionary match statistics for other reference samples. Hence, shortly after the above passage, Dr Perlin advised the jury of the match statistics for Irene Lin for three contributors and then referred to achieving “better separations, particularly from the male genotypes” in the results for Irene Lin for runs involving four and five assumed contributors. [479] This was a reference to the number of rows in the attached schedule where inclusionary match statistics were yielded for Irene Lin but not for her male relatives (such as rows 34 and 35). In contrast, the effect of Dr Perlin’s evidence in relation to “shadowing” and Brenda Lin is that compared to Irene Lin she was not separated out from the higher match statistics yielded by Min, Terry and Henry Lin. [480] Further, in the voir dire Dr Perlin was asked whether any analysis was undertaken to gauge TrueAllele’s response to shadowing. He said that “would be the five contributor results” because that was “assuming enough contributors”. [481] Thus, the entire premise of the discussion about separation and shadowing before the jury and on the voir dire was that sometimes the same inferred contributor yielded multiple inclusionary match statistics especially for reference samples from related individuals. The real issue before the jury was what that meant in relation to Brenda Lin compared to Irene Lin and possibly her sister, Lily Lin.

6. [222]

   The concept of separation in relation to reference samples that share allele pairs also arose in the cross‑examination of Dr Perlin at the 2016 trial. It was suggested to Dr Perlin that: [482]

7. [223]

   At the 2016 trial, Dr Perlin reiterated that achieving better separation depends “more on the relative proportions than on the genetic commonality”. [483] He made the same point during his evidence on the voir dire, noting that, if the mixture has a “50/50 ratio of the two components”, then “you’re not going to get the complete separation by any method”. [484] Even so, he said the result is not “wrong information” just “less information”. [485]

8. [224]

   The above analysis was confirmed by Dr Perlin’s evidence in this Court. Dr Perlin stated that it was incorrect to conclude that, if TrueAllele assumes three contributors and consequently produces a probability distribution for each inferred contributor, then it will precisely correspond with each reference sample. [486] He stated that when TrueAllele is asked to assume fewer contributors than the actual number of contributors then “we will often see a super [im]position of the people’s genotypes in one of those partially separated contributors”. [487] He also explained that this was likely where the individuals who provided the reference sample, in this case the victims, were related and thus shared allele pairs. [488] Hence, in this Court Dr Perlin was asked as follows: [489]

9. [225]

   In the emphasised passage, Dr Perlin pointed out the fallacy that a “particular inferred contributor” necessarily corresponds with a reference sample. Later in his evidence he confirmed that, if one reference sample was producing multiple high inclusionary statistics for different inferred genotypes that was “not a problem if you have partial separation”. [490] He confirmed that if the data was yielding partial separation, then it would be appropriate to run TrueAllele assuming a greater number of contributors. Later in his evidence, he confirmed that the data in this case showed that when five contributors were assumed a “better separation” was achieved. [491]

Reporting of Match Statistics and Shadowing

1. [226]

   A number of the complaints in the appellant’s written submissions concern the match statistics that Dr Perlin provided to the jury for each of the reference samples, including Brenda Lin. By reference to a comparison of the match statistics reported by Dr Perlin to the jury with the figures in Annexure 1, [492] the appellant’s written submissions made various contentions about the supposed inconsistencies between Dr Perlin’s evidence on the one hand and TrueAllele’s results on the other, as well as the general unreliability of both. [493]

2. [227]

   As with most of the other issues raised on appeal concerning the DNA evidence, none of these complaints were raised at the 2016 trial. Dr Perlin summarised some aspects of reproducible and reportable results to the jury at the 2016 trial. [494] No objection was taken to the figures he reported. As noted, the source of the figures reported by Dr Perlin to the jury, namely Annexure 1, was known and available to all the counsel who appeared for the appellant at his various trials. There was no cross‑examination of Dr Perlin at the 2016 trial about his approach to reporting figures save for the questions directed to shadowing.

3. [228]

   To address these complaints, it is first necessary to describe in more detail Dr Perlin’s approach to reporting match statistics. Given that this issue was not raised at the 2016 trial, this must be undertaken by reference to the evidence adduced on the voir dire and, in some respects, by reference to the evidence adduced on appeal. This only reinforces the difficulty noted above about the different issues that were being determined at the voir dire, the 2016 trial and on appeal. In any event, none of the appellant’s complaints are established.

4. [229]

   During the voir dire, Dr Perlin stated that if TrueAllele does not “give reproducible results, then they’re not reported”. [495] He described the factors relied on to determine a reportable statistic as concordance of results across multiple runs, [496] concordance of mixture weight [497] and a relatively high KL score as that is a measure of the expected log of a match statistic of an “individual who did contribute that DNA sample”. [498] Dr Perlin said that a KL score “like 6,7,8” indicates that a high match statistic is likely to be meaningful, whereas a score such as “2 or 3” indicates the match statistic is likely to be “less … informative”. [499] Dr Perlin stated that the reporting of results involves choosing a “representative run”, which will typically be the median. [500] (He told the jury at the 2016 trial that he would report a “typical value”. [501] ) During the voir dire, Dr Perlin stated that the comparison was between log values as opposed to absolute values. Hence, he would regard two match statistics of 9.6 quadrillion and 27 quadrillion as concordant. Even though there is a difference of over 17 quadrillion they are still “within a factor of ten”. [502] The effect of Dr Perlin’s explanation was that a consideration of concordance extends to considering results for runs of TrueAllele that assume a different number of contributors. [503]

5. [230]

   Under cross‑examination during the voir dire, Dr Perlin explained that some match statistics are not reportable because they are not “informative”, either because of a low KL statistic or a match statistic “that hover[s] around a likelihood ratio of zero”. [504] He also explained that a “false positive” included a match statistic that yielded discordant results and nominated non-donor relatives of donors as an example: [505]

6. [231]

   So far as the match statistics for Min, Henry and Terry Lin are concerned, during the voir dire and in response to a suggestion that he had “cherry‑picked” the most favourable statistics for the Crown in relation to Stain 91, Dr Perlin produced the following table derived from Annexure 1: [506]

7. [232]

   The match statistics in the three right hand columns are taken from Annexure 1 and rounded down. The red figures correspond with the figures that Dr Perlin provided to the jury at the 2016 trial for Min, Henry and Terry Lin. [507] They are marked in orange on Annexure 1 along with the figures that Dr Perlin provided to the jury for Irene, Lily and Brenda Lin at the 2016 trial.

8. [233]

   During the voir dire, Dr Perlin was asked about the above summary by the Crown Prosecutor as follows: [508]

9. [234]

   During the voir dire, Dr Perlin was cross‑examined on this summary by Senior Counsel for the appellant. Dr Perlin stated: [509]

10. [235]

    On appeal, the Crown submitted that each of the match statistics provided by Dr Perlin to the jury at the 2016 trial were concordant with other match statistics in Annexure 1. As noted, the figures in orange in Annexure 1 are the figures provided by Dr Perlin to the jury at the 2016 trial. Marked in yellow are either concordant figures, as suggested by the table provided by Dr Perlin during the voir dire set out above, or figures that the Crown contends are consistent with his description of concordance set out above. [510] It was necessary for the Crown to take the latter step given that the complaints about the match statistics reported at the 2016 trial are being raised for the first time on appeal. The Crown submitted that, for each of the “statistics that Dr Perlin reported in his evidence at trial, a concordant result was able to be obtained on another independent run, in relation to both match statistic and, critically, mixture weight”. [511] This submission should be accepted with the additional observation that so far as each of Min, Terry, Henry and Irene Lin are concerned there were concordant results within TrueAllele runs involving three, four or five assumed contributors, as well as concordant figures across those runs.

11. [236]

    Two of the appellant’s particular complaints that were levelled at this aspect of Dr Perlin’s evidence have already been addressed, namely, the contention that there was something inherently problematic in the yielding of multiple match statistics for the same inferred contributor, [512] or vice versa, [513] and the supposed “problem” presented by lower match statistics derived in respect of inferred genotype probability distributions with calculated contributions of less than 10%. [514]

12. [237]

    The balance of the complaints concern what match statistics set out in Annexure 1 Dr Perlin chose to inform the jury of in answer to particular questions. These contentions bring to the fore the completely new case that is being sought to be mounted on appeal. The essence of the complaints made for the first time on appeal is that Dr Perlin should have, but did not, give the jury other match statistics in circumstances where his own counsel could have, but did not, elicit them. Such a submission has little initial attraction and it did not become more persuasive as the appeal progressed.

13. [238]

    The appellant’s submissions referred to row 13 of Annexure 1 which sets out the match statistics for an inferred contributor of 11% weight on a four assumed contributor run of TrueAllele that involved 100,000 simulations. It yielded match statistics of 4.45, 4.37 and 4.71 for Lily, Irene and Brenda Lin respectively. [515] The submissions referred to the evidence set out at [159] in which Dr Perlin addressed Brenda Lin’s match statistics in his evidence‑in‑chief. It was submitted that, although Dr Perlin mentioned Brenda Lin’s “presence” in this genotype at the 2016 trial, “the fact that her match statistic was higher than her mother and aunt was clearly not explained – the opposite impression was given by the evidence”. [516] In oral submissions on appeal, Senior Counsel for the appellant referred to this row and the figure Dr Perlin mentioned in [159] of 3.16, but noted that he did not report they corresponded to an inferred genotype that was said to be a male genotype. [517] It was submitted that Dr Perlin “entirely and inappropriately glossed over” these two figures (ie, 4.71 and 3.16) in his evidence at the 2016 trial. [518]

14. [239]

    To address this, it is necessary to return to the evidence set out at [159]. The figures reported to the jury at the 2016 trial for both Lily and Irene Lin included figures referable to row 13 of Annexure 1. [519] The Crown’s analysis demonstrates that there were concordant figures for each of those figures (see row 19 of Annexure 1). In the passage set out at [159], Dr Perlin commences by considering the figures for the same row for Brenda Lin as he refers to the 11% contributor (ie, row 13), but then mentions a number in the “thousands”, being 3.16 (ie, row 19). He then states that “with four contributors, the numbers were similar, they were all in the thousands and all in fraction – separation that involved other relatives, brothers or – so the numbers went in the thousands with some shadowing relatives”. He then refers to Brenda Lin’s highest figure of 4.91 in row 25 which is based on the assumption of five contributors and which he describes as “shadowing [her] brothers and her father”. [520]

15. [240]

    In cross‑examination at the 2016 trial, counsel for the appellant returned to the evidence set out at [159] and in particular to the match statistic of 3.16 for row 19. [521] Dr Perlin stated that he thought he had commented, or at least intended to comment, on the match statistic of 3.69 in row 18 which he described as Brenda Lin shadowing her male relatives. [522] The cross‑examination then focussed on the match statistic of 4.91.

16. [241]

    While Dr Perlin’s evidence may reveal some confusion as he moved through Annexure 1, it does not give the “opposite impression” about the 11% component. Dr Perlin referred to Brenda Lin having a match statistic for four contributors in the “tens of thousands” which she did, namely 4.71. Instead, Dr Perlin focussed on the highest match statistic for Brenda Lin, namely 4.91. It was always open to counsel for the appellant to clarify the other figures in Annexure 1 and seek Dr Perlin’s opinion on whether they demonstrated concordance or were inconsistent with shadowing. To an extent, trial counsel did this in that he returned to cross‑examine on the figure of 3.16. However, given that row 13 revealed a much higher match statistic for Min Lin, that figure became the focus of the cross‑examination.

17. [242]

    In oral evidence on appeal, Dr Perlin was taken to the match statistics for Lily, Irene and Brenda Lin for row 13 (ie, 4.45, 4.37 and 4.71). He agreed that based on that “one isolated contributor” there was nothing to distinguish between them, but emphasised the need to consider all the data. [523] He was referred to the same figures in row 19 (ie, 4.04, 4.73 and 3.16) and was asked whether “looking at those two runs together” they could not be separated. He agreed that was “possible” but repeated that a consideration of whether Brenda Lin’s genotype was an “outlier” was not restricted to considering one or two rows of Annexure 1. Instead, he stated that looking at all the data Brenda Lin was “matching too much” [524] and she is “just appearing all the time with her brothers”, whereas “[w]e don’t see the other women appearing in the male fractions”. [525] Dr Perlin was asked: [526]

18. [243]

    Dr Perlin’s evidence on appeal does not support the proposition that he “entirely and inappropriately glossed over” the match statistics of 4.71 and 3.16. No such suggestion was put to him in cross‑examination in this Court.

19. [244]

    The appellant’s written submissions queried why, in his evidence at the 2016 trial, Dr Perlin described Brenda Lin’s match statistic of 1.84 for the 35% contributor to a three contributor run (row 4) as referable to a “male genotype” when he said that result was just shadowing the higher match statistics of her male relatives. [527] Based on the material adduced at first instance including during the voir dire, it seems that row 4 described a male genotype because the inferred probability distribution for that contributor includes a figure at a particular locus (“AMELO”) that shows that the probability of that genotype being male was greater than 99%. [528]

20. [245]

    The appellant’s written submissions criticised Dr Perlin for not mentioning to the jury at the 2016 trial Brenda Lin’s match statistic of 2.41 for the 11% contributor for five contributors (row 22). Similar complaints were made about the absence of any reference to her match statistics of 4.71 (row 13), 3.16 (row 19), 3.26 (row 12) and 3.69 (row 18). [529]

21. [246]

    The figures of 4.71, 3.16, 3.69 and 2.41 were taken up with Dr Perlin in cross‑examination at the hearing of the appeal. His response in relation to the match statistics of 4.71 and 3.16 are addressed above. As for row 18, in his oral evidence on appeal, Dr Perlin noted the high match statistic for Min Lin (7.05), Terry Lin (5.01) and Henry Lin (3.39), as well the inferred genotype which suggested “almost 90 percent of this fraction being male and 11 out of the 20 loci have an exact genotype between Brenda and one of her two brothers” as demonstrating shadowing. [530]

22. [247]

    In relation to the match statistic in row 22 of 2.41, Dr Perlin said that “we also look at the data”, being a comparison of the inferred genotype probability distribution to the genotypes of the reference samples, including Irene Lin. He said that “with Irene we see low level peaks in the data across her loci where there are nine small peaks for Irene that can only be accounted for by her genotype and no one else's”. [531] Dr Perlin added that “that is more evidence in explaining the data that Irene is likely to have left her genotype because it's the simplest explanation of where those nine peaks as alleles that are not associated to anybody else might have come from”. [532] Irene Lin’s match statistic for that contributor was 5.23 compared to Brenda Lin’s match statistic of 2.41. The significance of Irene Lin’s allele pairs is that she did not share as many allele pair types with Henry and Terry Lin as Brenda Lin. [533]

23. [248]

    Later in the cross‑examination on appeal, Dr Perlin was asked: [534]

24. [249]

    This question is the only occasion during his cross‑examination on the appeal where it was suggested to Dr Perlin that he deliberately refrained from reporting a match statistic (or otherwise acted improperly). It is a completely untenable suggestion given that the figure he is said to have deliberately not provided was set out in the document that he was quoting from at the 2016 trial and had been provided by him to the Court and the parties over two years previously.

25. [250]

    The match statistic of 3.26 in row 12 referred to in the appellant’s written submission was not taken up with Dr Perlin in his cross‑examination on appeal. Consistent with Dr Perlin’s description during the voir dire of reporting concordant results, the absence of any reference to this figure appears to follow from the absence of any concordant figure for that number of assumed contributors and that weight of contributor.

26. [251]

    The appellant’s written submissions referred to the results for four contributors in rows 18 to 21 (ie, the 200K rep cycle). [535] They note that Min and Terry Lin produced inclusionary match statistics for all inferred contributors and that the same inferred contributor (row 20) was the source of the reported figures for both of them, [536] a matter that has already been addressed. The submissions also assert that row 19 was the basis for a reported figure for Irene Lin, even though a similar inclusionary figure was said to have been produced for Lily Lin and inclusionary match statistics were yielded for Terry and Min Lin. [537] In fact, they were the source for Lily Lin’s reported figure (4.04). [538] That figure was less than the figure for Irene Lin (4.73) which was not reported as the 4.37 in row 13 was. This only demonstrates that Dr Perlin was not “cherry picking” the highest result but seeking to report a median concordant result. The match statistics for Terry and Min Lin in row 19 were much lower and were neither reported, nor said to be concordant. The same observation applies to a complaint by the appellant about Dr Perlin providing the jury with the match statistics for Irene and Lily Lin in row 22, [539] and only providing the jury with the match statistic for Henry Lin in row 26. [540]

27. [252]

    On appeal it was suggested that with row 27 and the 1% contributor, Dr Perlin should have told the jury that a non-inclusionary statistic for that row did not rule out anyone as a contributor. Dr Perlin disagreed. In the context of having “apparent inclusionary statistic[s] at four other contributors” it was not relevant, in that “if you don’t find any connection and there is nothing to report”. [541]

28. [253]

    In his written submissions, the appellant sought to draw further support from his complaints about the reporting of match statistics from the multiple positive match statistics that TrueAllele determined from the Profiler Plus (9 loci) and Identifiler (15 loci) results which used less loci than PowerPlex 21 (21 loci). The appellant noted that the Profiler Plus results “show that each of Terry and Brenda Lin received an inclusionary match statistic for every single contributor, on every single reported run, on the assumption of all 3, 4 and 5 contributors”. [542] The appellant observed that, for Profiler Plus, Terry Lin received the highest match statistic on every reported run and as he could not have been “all these separated out contributors” this suggests that, if anyone else in the family was the relevant contributor, “they nonetheless received a lower match statistic than did Terry Lin” [543] and that otherwise for most of the runs Brenda Lin received a higher match statistic than Irene or Lily Lin. [544] With the TrueAllele results for Identifiler, there were no inclusionary results for Irene Lin for any runs involving three contributors and to the extent there were inclusionary results for Irene and Lily Lin they were lower than Brenda Lin’s. [545]

29. [254]

    Dr Perlin was not cross‑examined on the TrueAllele results using Identifiler or Profiler Plus at the 2016 trial. It was only briefly touched upon during the voir dire when Dr Perlin observed that the results showed “concordance between the three kits”, as all three produced “largely… positive log ratios …”. [546] On appeal no questions were directed to Dr Perlin concerning the TrueAllele results for Identifiler or Profiler Plus.

30. [255]

    The Crown submitted that the appellant’s analysis of TrueAllele’s results using Identifiler or Profiler Plus overlooks the evidence given by Dr Perlin about the reporting of results by reference to concordance and not simply identifying the highest statistic either for a given reference genotype or a given portion of the mixture weight. [547] The Crown further submitted that, because both sets of results show inclusionary match statistics on almost every line for Brenda Lin that are always exceeded by at least one and often more of her male relatives, with almost no positive statistics for Lily or Irene Lin, then that strongly supports Dr Perlin’s evidence that Brenda Lin was shadowing her male relatives. [548] The Crown also submitted that these statistics show the difficulty with achieving separation. [549]

31. [256]

    The Crown’s submissions are entirely plausible. They are bolstered by the observation that the KL statistic for the TrueAllele runs for both Profiler Plus and Identifiler are far less than for PowerPlex 21, which presumably is to be expected with less identifying data (see above). However, in the end result it is not necessary to positively determine this dispute. In the absence of cross‑examination of Dr Perlin on this topic on any of the numerous occasions he gave evidence at first instance, as well as for two days of the appeal, the appellant has not satisfied the Court to the relevant standard that the TrueAllele results for Profiler Plus or Identifiler undermined TrueAllele’s results based on the PowerPlex 21 results or Dr Perlin’s evidence at the 2016 trial.

Dr Perlin’s Qualifications to Express Opinions and Validation

1. [257]

   The appellant’s written submissions addressed at length the topic of Dr Perlin’s degree of “specialised knowledge”, including the extent of the validation of TrueAllele. [550] The submissions were directed to an overall complaint made under Grounds 1 to 3 that Dr Perlin did not have the appropriate “specialised knowledge” to opine in the way he did about the match statistics, especially to express opinions concerning “shadowing”. [551] It was also submitted that he otherwise misrepresented the effect of the validation studies. [552] The submissions on this ground are also directed to a particular to Ground 8 which alleges incompetence on the part of the appellant’s trial counsel because of his alleged failure to “take issue with Dr Perlin’s incorrect evidence about independent validation for four and five related contributor mixtures”. [553]

2. [258]

   In summary, the combination of Dr Perlin’s qualifications and experience, the various studies and papers that were tendered on the voir dire and Dr Perlin’s explanation of the relevance of their results to his opinions was a more than sufficient basis to conclude that Dr Perlin had the requisite “specialised knowledge” to opine on the effect of the match statistics, including shadowing, and that his opinions were wholly or substantially based on that knowledge (Honeysett v The Queen (2014) 253 CLR 122; [2014] HCA 29 at [23]; “Honeysett”). Otherwise, a complaint about a lack of “validation” of a scientific theory or opinion does not of itself raise any issue under s 79 of the Evidence Act 1995 and, in any event, it was not demonstrated that there was anything relevantly inadequate in the validation of TrueAllele. To explain these conclusions, it is first necessary to describe some of the evidence about validation that was adduced at first instance so far as it is relevant to multi contributor DNA mixtures and related contributors, as well as comparisons to non-contributing relatives of the donors.

3. [259]

   During the voir dire, 52 articles, papers or reported judgments concerning TrueAllele or its methodology were tendered. [554] Dr Perlin wrote or contributed to some of these papers. Included in this material were papers concerning validation studies undertaken by or on behalf of various crime laboratories. In his evidence‑in‑chief on the voir dire Dr Perlin was taken through these studies. [555] It is only necessary to note six.

4. [260]

   The eighth paper that Dr Perlin was taken to was the “New York State Police Crime Laboratory System, TrueAllele Casework Validation Addendum”, dated June 2013, which validated TrueAllele for two and three person mixtures (the “June 2013 New York Addendum”). [556]

5. [261]

   The ninth paper that Dr Perlin was taken to was the “New York State Police Crime Laboratory System, TrueAllele Casework Validation Addendum”, dated 9 December 2013 (the “December 2013 New York Addendum”). [557] This report describes the results of two studies, one involving four person mixtures and the other being a familial study. The latter involved “a suite of two person mixtures in ratios of 1:1 and 3:1 from two separate families”, each having four non‑identical full siblings, as well as parent offspring combinations. [558]

6. [262]

   The conclusion from the four contributor studies was that “TrueAllele … is still capable of providing robust, donor‑specific match statistics for mixtures of up to four contributors”. [559] In relation to the familial study, the December 2013 New York Addendum concluded that “[w]hile cross matching between full siblings and parents was observed, the highest match statistics were always associated with the true donors in all mixtures tested” and the “[m]ean log(LR) separation between donors and related non-donors was shown to improve dramatically when mixture weights were unequal ...”. [560] The reference to “separation” in this context is to the difference between the match statistic of a donor and the match statistic of a related non‑donor. Various charts included in the December 2013 New York Addendum generally showed a large difference between those figures. In a few instances a positive match statistic was yielded for a non-related parent donor. Most were only just above log1 or log2, [561] however, one plot for a related non-donor sibling showed a match statistic above log5 [562] (see below at [285]). The December 2013 New York Addendum noted that where there was a high degree of allele-sharing this resulted in understated match statistics. [563] This was consistent with the evidence of Dr Perlin and Ms Neville that complexity will be reflected in reduced match statistics. [564]

7. [263]

   In his evidence on the voir dire concerning the December 2013 New York Addendum, Dr Perlin explained that the results of the “family studies” experiment show “a shadowing and what the shadowing is showing is that relatives can have a match statistic that is in between a true donor and a non‑donor and it typically shadows around six zeros more or less as a match statistic”. [565] He agreed that “shadowing [is] caused by sharing of alleles among related people”. [566] This discussion of “shadowing” was proffered before there was any suggestion by the defence that Brenda Lin’s DNA might be present in Stain 91.

8. [264]

   The tenth report referred to by Dr Perlin was the “TrueAllele Genotype Identification on DNA mixtures containing up to five unknown contributors” by Cybergenetics Pittsburgh and Kern Regional Crime Laboratory, dated 15 February 2014 (the “Kern County report”). Dr Perlin said that this was performed in collaboration with the Kern County Crime Laboratory, which uses TrueAllele. [567] This study validated TrueAllele for up to five unknown contributors. [568] As noted in the appellant’s written submissions, no issue of relatedness of donors or non-donor comparisons was addressed in this report. The report also reported that specificity was tested by use of “10,000 genotypes that were randomly generated from an ethnic allele frequency distribution”. [569] The report noted that the false inclusion level increased with contributor number and “[t]here were few false matches beyond an LR of 10, and essentially none (6 events in 8,400,000) with an LR > 1,000”. [570]

9. [265]

   The twelfth paper was a cybergenetics paper authored by Dr Perlin and others titled, “TrueAllele Casework Separates DNA mixtures that Share Alleles”, dated 12 March 2014. [571] It was a validation study that reported on TrueAllele’s performance with synthesised DNA mixtures of two persons with different levels of allele sharing between contributors. [572] Dr Perlin explained that it was prepared from data generated by another organisation that either did not complete or write up their validation report. [573] He explained that it has: [574]

10. [266]

    Dr Perlin stated that the study showed there was “no significant difference in [TrueAllele’s] reliability based on the amount of [a]llele sharing”. [575]

11. [267]

    The fifteenth report was titled, “Australia TrueAllele Validation report” and dated September 2011 (the “Australian Validation Report”). [576] It was the validation report for TrueAllelle for the NSW police service and assessed two contributor mixtures, three contributor mixtures and three contributor mixtures with one degraded contributor. [577] The study reported on also involved analysing eight relatives of the mixture contributors as contributor samples. [578] With those it was concluded that “when there is allele sharing with a relative [non‑donor], there can be a small degree of positive log(LR) that is inconclusive for a match”, but “[o]therwise, the Log(LR) values tend to be overwhelmingly negative, indicating that TrueAllele has high specificity and does not produce false matches”. [579] This is consistent with the December 2013 New York Addendum. As noted above, by the time of the 2016 trial TrueAllele had been validated in Australia for four contributors.

12. [268]

    The twenty third paper was a PowerPoint presentation titled, “Pushing the limits of TrueAllele casework”, dated 12 May 2013, and prepared by Susan Greenspoon PhD from the Virginia Department of Forensic Sciences (the “Greenspoon slide presentation”). [580] Dr Perlin described Ms Greenspoon as “essentially” responsible for validation at that Department and “their main staff scientist for assessing technology and science methods”. [581] According to Dr Perlin the presentation addressed “how the system performed on challenging two, three and four person mixtures”. [582] One part of the presentation concerned mixtures where the contributors were not related to each other but comparisons were undertaken with parents or siblings of the contributors. The effect of the study was that first-degree relatives of two person mixtures were excluded and that some results for first degree relatives of three or four person mixtures were slightly positive but not reproducible. [583] A slide headed “CONCLUSION” stated that TrueAllele is “accurate”, “highly specific”, “sensitive” and “might produce a small positive score for a first degree relative for 3 and 4-person mixture”. [584]

13. [269]

    At the commencement of his cross‑examination on the voir dire, Dr Perlin was asked as follows: [585]

14. [270]

    This part of Dr Perlin’s evidence strikes at the heart of one of the principal complaints made about validation on appeal, namely the necessity for there to be validation of four or more contributors who are related and comparisons of those four donors with non‑donor relatives. [586] Instead, Dr Perlin’s evidence was that the validation of the number of contributors and relatedness between donors, as well as between donors and non‑donors, could be addressed separately in that one was “not terribly relevant” to the other.

15. [271]

    A statement of Ms Neville dated February 2014 was tendered on the voir dire. [587] She stated that a “small TrueAllele processing system” had been purchased by NSW and a review commenced but validation was not progressed as another system was chosen based on cost and running time. [588] Annexed to her statement was a report of the review team dated July 2011 which considered two and three person mixtures. However, in her oral evidence at the voir dire, Ms Neville stated that a “further body of work” was undertaken and she considered that TrueAllele had been “validated” and she considered it was “reliable”. [589] As noted, the Australian Validation Report concerning the validation for TrueAllele for three contributors was tendered on the voir dire.

16. [272]

    The evidence given by Dr Perlin (and Mr Walton) to the jury at the 2016 trial on the subject of validation is summarised above. [590] As noted, in cross‑examination Dr Perlin was challenged on the extent of the validation for TrueAllele including in relation to “complex mixtures that exceeded three contributors” and concerning “complex mixed samples involving related individuals in respect of contributors more than three in number”. Dr Perlin rejected the suggestion that TrueAllele was not validated. He nominated three papers “off the top of my head”. Those papers were “a study done independently by the New York State Police ...”, a “Virginia Department of Forensic Science [report] that looked at four contributors and relatives” and a “study from the Duquesne Masters Student”. [591] The first of these is the December 2013 New York Addendum.

17. [273]

    As noted, in re‑examination Dr Perlin nominated various papers that addressed those and other topics raised with him. [592] The papers he identified were listed in Exhibit GD, although the articles themselves were not tendered.

18. [274]

    Exhibit GD identified ten papers as addressing “[a]llele overlap with three or more contributors”, four of which were independent of TrueAllele. Dr Perlin said that “all the studies with mixtures, particularly with three or more contributors, have overlapping alleles”. [593] The papers listed in this category were numbered 15, 18, 26, 27, 28, 29, 30, 31, 32 and 33.

19. [275]

    Paper 15 was the June 2013 New York Addendum and paper 18 was the December 2013 New York Addendum. Paper 26 was described as “K. Guest, L. Ludivico, L. Ferra, and MK. Perlin ‘Development of Kinship Mixtures and Subsequent Analysis Using TrueAllele Casework’ Master’s Thesis, Duquesne University (Pittsburgh, PA), April 2015” (the “Master’s Thesis”). This is the Master’s Thesis that Dr Perlin referred to in cross‑examination. [594] Dr Perlin described this paper as providing validation for “up to five contributors”. [595]

20. [276]

    Paper 27 was described as an article published in the Journal of Forensic Science in 2015 of which Dr Perlin was one of the authors, titled “TrueAllele genotype identification on DNA mixtures containing up to five unknown contributors”. Paper 29 was described as “Establishing the limits of TrueAllele Casework: a validation study” by Greenspoon SA, Schiermood-Wood L and Jenkins BA, which was published in the Journal of Forensic Sciences in September 2015 (the “Greenspoon Paper”). Its name implies that it was related to Ms Greenspoon’s slide presentation that was tendered on the voir dire. Dr Perlin said that this was “an independent peer reviewed paper, out to four contributors”. Given that Ms Greenspoon was associated with the Virginia Department of Forensic Science, it seems that this was the third paper that Dr Perlin referred to in the extract from his cross‑examination set out above. [596]

21. [277]

    Paper 30 was another article of which Ms Greenspoon was one of the authors. Dr Perlin told the jury it concerned validation “out to four contributors”. [597] The other four papers were described in Exhibit GD in terms suggesting they were internal validation reports for police departments in Baltimore, Beaufort County, Georgia and the Acadiana region of Louisiana. Dr Perlin stated that three of those reports validated TrueAllele out to five contributors and one validated TrueAllele out to six contributors. [598]

22. [278]

    Exhibit GD listed four papers as addressing the circumstance of “[m]ixed contributors with more than three contributors and up to five contributors where kinship was specifically addressed”. The papers listed were the Australian Validation Report, the Master’s Thesis, the December 2013 New York Addendum and the Greenspoon article. Exhibit GD nominated the last two as independent. In the extract from his cross‑examination set out above, [599] Dr Perlin described this report as “look[ing] at up to five mixtures of five related persons”. [600] So far as the Australian Validation Report is concerned, the description in Exhibit GD was inaccurate as it only addresses mixtures of up to and including three contributors but no more (although it was later validated to four). However, it did address kinship.

23. [279]

    At the hearing of the appeal, the appellant sought to read an affidavit from his solicitor attaching, inter alia, the Master’s Thesis and the Greenspoon article. They were listed in Exhibit GD but were not tendered on the voir dire or at the trial. [601] At the time the affidavit was read, the Court indicated that the affidavit would be received provisionally and that its admissibility would be addressed in the Court’s judgment. [602] The admissibility of the affidavit is addressed below, [603] although for present purposes it is necessary to describe the articles that were attached to it.

24. [280]

    As suggested by its title, the Greenspoon article reported on the study that was the subject of the Greenspoon slide presentation tendered during the voir dire. The conclusion of the Greenspoon article was that the “studies reported herein demonstrate that, even with complex four-person mixtures, [TrueAllele] is capable of supporting an accurate, sensitive, and specific analysis”. [604] Otherwise, there is no material difference between the analysis and the conclusions in that report and what was explained in the Greenspoon slide presentation supplemented by Dr Perlin’s oral evidence during the voir dire as set out above. However, two aspects of the appellant’s submissions about the Greenspoon article should be noted.

25. [281]

    First, the appellant described this paper as reporting that “[p]roblems were identified if a minor donor contributed less than 10% by weight”. [605] In fact, the paper noted that TrueAllele offered “great specificity and discriminating match statistics unless the minor contributor was less than a 10% contributor to the mixture” and then added “[w]hen the minor contributor provided only a very small proportion of the DNA in the mixture, the match statistic reflected that weak contribution with uncertainty resulting in lower match statistics”. [606] This reinforces the point made above, namely that the match statistic produced by TrueAllele quantifies the uncertainty that follows from having a smaller inferred contribution.

26. [282]

    Second, the appellant’s written submissions referred to the (small) positive results that were sometimes obtained for non‑donor relatives in this study. [607] However, they were only marginally positive and mostly not reproducible. In any event, the occurrence of positive results for a non‑donor relative who shares alleles with the contributors was the premise of Dr Perlin’s evidence on shadowing.

27. [283]

    The Master’s Thesis reported on testing of related donors to two, three, four and five person mixtures. It did not involve any comparison to a related non‑donor. The conclusion of the thesis was that “match statistics could be obtained for two person, three-person, four-person, and five-person mixtures involving kinship” and that, while further testing needs to be undertaken, the “results also suggest that match statistics can be obtained for mixtures when the contributors are present at different mixture ratios and when there are different relationships between the contributors”. [608]

28. [284]

    As noted, at the hearing of the appeal in this Court Dr Perlin was cross‑examined about his opinions regarding Brenda Lin and “shadowing”. He was asked about the basis of his knowledge to opine on that subject and referred, inter alia, to the December 2013 New York Addendum Report. [609] It was suggested to Dr Perlin that the report was of limited utility because it concerned a comparison between a related two person mixture and a related non‑donor. Dr Perlin explained that it was “an excellent study for understanding this situation” because it was “very similar to the situation we have here with the two siblings, Terry and Henry, who are likely to have left DNA” with Brenda Lin being the possible related non-donor. [610]

29. [285]

    In cross‑examination, Dr Perlin was referred to row 13 of Annexure 1 which attributed to Brenda Lin a match statistic of log4.71 for an 11% contributor on a four assumed contributor run. This was only marginally less than Henry Lin’s match statistic (log5.36) and log2.5 less than Min Lin’s match statistic (log7.18) (and otherwise comparable to Irene and Lily Lin’s match statistics of log4.37 and log4.45 respectively). It was suggested to Dr Perlin that none of the studies that described what he refers to as shadowing yielded a difference between “a contributing reference sample and a non‑contributing relative which are within the same log range or one two log ranges [of] one another”. [611] Dr Perlin rejected that suggestion. He pointed to the December 2013 New York Addendum and, in particular, a “regression line” in that report that shows the greater the level of allele sharing then the higher the match statistic for the related non‑donor [612] as follows:

30. [286]

    Dr Perlin explained that the maximum number of shared alleles in this scatterplot was 26 because 13 loci were reviewed in the December 2013 New York Addendum. He said this plot shows that “the greater the allele sharing the more the non‑donor [is] shadowing”, with potentially high match statistics for the non-donor relative. [613]

31. [287]

    As noted, one of the principal complaints made on appeal concerns the supposed lack of any qualification or scientific knowledge on the part of Dr Perlin to give evidence on any relevant topic other than the bare match statistics revealed by a run of TrueAllele including, but not limited to, the contention he was not qualified to opine on the topic of “shadowing”. Variants on this complaint are found in the submissions in support of Grounds 1, 2 and 3 which are generally directed to different stages of the trial process, namely, the state of the evidence at the voir dire, the 2016 trial and as shown on appeal.

32. [288]

    The appellant’s submissions on this issue repeated the points addressed above, namely, the supposed difficulty with multiple inclusionary results for one inferred contributor [614] and the large number of theoretical genotypes that could better explain the data. [615] However, the appellant also submitted that “[t]here is no basis shown on Dr Perlin’s evidence, reports, witness statements or validation studies/articles … [that] … support the idea that … he has knowledge to start nominating one rather than the other as having been the true contributor in nature”. [616] This involves a misstatement of Dr Perlin’s evidence. Dr Perlin produced a reportable figure having regard to concordance (being a “typical” or median value). [617] The basis upon which he did so is explained above and it is clearly based wholly or at least substantially on his qualifications, study and experience.

33. [289]

    In the context of addressing Dr Perlin’s specialised knowledge, the appellant also contended that the use of the term “false positive” was inappropriate and should only be used when an inclusionary statistic is produced for someone known not to have contributed. [618] In its submissions, the Crown stated that it “understood this submission as [contending] that all [match statistics] over log 3 were valid and reportable and should have been reported”. [619] That appears to be the point being made by the appellant. It is also addressed by the evidence given by Dr Perlin explaining the basis on which he reported the match statistics.

34. [290]

    The remaining aspect of the submissions concerning Dr Perlin’s specialised knowledge concerns the supposed absence of appropriate validation studies to support his expertise or knowledge, including in relation to shadowing. It is encapsulated by the following contention which concerns Ground 2 of the appeal: [620]

35. [291]

    To the extent that the studies concerned relatedness and multi contributor samples, the Greenspoon article (and earlier slide presentation) addressed four non‑related contributors and involved a comparison with non‑donor relatives of some of the contributors, even though the donors were not related to each other. The Master’s Thesis addressed related donors in a four-person contribution but did not make comparisons with related non‑donors. The December 2013 New York Addendum addressed relatedness in a separate study to its study of four contributor samples.

36. [292]

    The appellant notes that these studies did not “show ... any consideration of non-donor relatives to a mixture more complex than itself containing two related persons”. In essence, it is submitted that none of the various validation studies addressed the suggested circumstances of this case so far as Brenda Lin was concerned, namely, a DNA mixture of three or more related donors and a comparison to a suggested related non-donor. This is correct and, as addressed below, Dr Perlin never suggested otherwise. However, the various studies did involve comparisons between some four person contributors to a four‑person mixture and non‑donor relatives, as well as related contributors to a four‑person sample. Moreover, as explained above, Dr Perlin said that the results from the December 2013 New York Addendum warranted the conclusion that the topics of the number of contributors and relatedness were “not terribly relevant” to one another and he otherwise said that relatedness was just a strong instance of allele sharing which had been addressed in a number of studies. To the extent that it is relevant, in his evidence on appeal he clearly explained how the results of the familial study discussed in the December 2013 New York Addendum of a two‑person related mixture and a related non‑donor was of direct relevance to his interpretation of the TrueAllele results for Brenda Lin. Whether the appellant found that explanation persuasive is irrelevant to whether it meets the test for admissibility, especially where it is sought to be applied retrospectively as the appellant in part seeks to do.

37. [293]

    The submissions of the appellant in support of the contention that Dr Perlin was not appropriately qualified to express opinions on any matter other than the match statistics yielded by TrueAllele were solely directed to the requirements of admissibility under s 79 of the Evidence Act. No reference was made to ss 135 or 137. [621] Section 79 specifies two conditions of admissibility, namely, the witness must have “specialised knowledge based on the person’s training, study or experience” and the opinion must be “wholly or substantially based on that knowledge” (Honeysett at [23]). The reference to “specialised knowledge” is to “knowledge which is outside that of persons who have not by training, study or experience acquired an understanding of the subject matter” and the “person's training, study or experience must result in the acquisition of knowledge”.

38. [294]

    In Honeysett, the opinion of an “anatomist” as to the commonality of the physical characteristics of the appellant and an offender captured on closed circuit television was held to be inadmissible as it failed the second condition described above. The opinion was held not to be wholly or substantially based on his specialist knowledge as an anatomist, but rather on his subjective impressions gained from reviewing the CCTV images (at [43]). The Court noted the appeal did “not provide the occasion to consider the appellant's larger challenge respecting the requirement of an independent means of validation before an opinion may be found to be based on ‘specialised knowledge’" (at [42]). However, the Court referred to an observation of Spigelman CJ in R v Tang (2006) 65 NSWLR 681; [2006] NSWCCA 167 at [137] (“Tang”) that “[t]he focus of attention must be on the words ‘specialised knowledge’, not on the introduction of an extraneous idea such as ‘reliability’” (Honeysett at [26]).

39. [295]

    Section 79 envisages an expert acquiring specialised knowledge from training, study or experience. Dr Perlin’s extensive scientific and academic qualifications are described above. Through his experience in developing, implementing and testing TrueAllele, including his participation in validation studies and his study of independent studies, he has clearly acquired “specialised knowledge” of probabilistic DNA analysis in general and the performance of TrueAllele in particular. This includes specialised knowledge concerning the match statistics or likelihood ratios of related donors and related non‑donors and their significance, including the phenomenon of shadowing. As noted, he referred to it during the voir dire having been demonstrated by the results of the December 2013 New York Addendum. [622] Through his answers he explained the connection between that knowledge and the opinions he expressed about the significance of match statistics, including Brenda Lin and shadowing. Contrary to the appellant’s submissions he clearly did have sufficient “specialised knowledge” to opine on those subjects.

40. [296]

    In the end result, this aspect of the appellant’s complaint of a lack of qualification on the part of Dr Perlin reduces to a contention that the absence of a validation study which the appellant contends is sufficiently analogous to this case was and is fatal to the admissibility of Dr Perlin’s interpretation of match statistics and opinions on shadowing. [623] The authorities require the rejection of that contention.

41. [297]

    The necessity or otherwise for a body of specialised knowledge to be “validated” was adverted to but not resolved in Honeysett. However, it was addressed in Tuite v The Queen (2016) 49 VR 196; [2015] VSCA 148 (“Tuite”). Tuite concerned a challenge to the admissibility of a DNA methodology that performed a similar function to TrueAllele (“STRmix”). The methodology was said to be “largely untested” and it was submitted that it had “not been generally accepted by the forensic science community” (at [4]). Having regard to Honeysett and Tang, Maxwell ACJ, Redlich and Weinberg JJA held that “the language of s 79(1) leaves no room for reading in a test of evidentiary reliability as a condition of admissibility” (at [70]). Their Honours explained this conclusion by reference to the following example (at [76] to [77]):

42. [298]

    Taken at its absolute highest, the appellant’s contention seeks to treat Dr Perlin’s opinions on shadowing as equivalent to the “new theory about the link between a particular form of lung disease and a particular industrial emission” referred to in this extract. Tuite is inconsistent with the contention that such a submission raises a matter within the province of s 79.

43. [299]

    As foreshadowed in the above passage, Tuite held that the reliability of a scientific opinion could be considered in determining whether to admit evidence of that opinion, but only when considering the application of s 137 and not in considering s 79 (at [85ff]). Relying on that Court’s earlier judgment in Dupas v The Queen (2012) 40 VR 182; [2012] VSCA 328 at [141] (“Dupas”), to the effect that an assessment of probative value involved an evaluation of “quality, reliability and weight of the evidence”, the Court of Appeal in Tuite observed that “the focus of attention for the purposes of assessing the reliability of scientific evidence should be on proof of validation” (at [102]). Their Honours nevertheless upheld the trial judge’s findings about the reliability of the methodology in issue in Tuite (at [129]).

44. [300]

    Insofar as Tuite held that s 79 is not concerned with the reliability of the expert’s opinions, it was followed in this Court in Chen v R [2018] NSWCCA 106 at [62] (“Chen”). To the extent that Tuite held that an assessment of the reliability of the scientific evidence, including by way of validation, was part of the assessment of “probative value” under s 137, then it is inconsistent with IMM v The Queen (2016) 257 CLR 300; [2016] HCA 14 at [52] (per French CJ, Kiefel, Bell and Keane JJ) (“IMM”).

45. [301]

    IMM left open the possibility that an assessment of the “reliability” of evidence may be permissible as part of an inquiry into the “danger of unfair prejudice” that would arise from its admission for the purposes of applying s 137 (IMM at [57]). It is not necessary to determine whether that is so, and, if it is, whether the admission of supposedly unvalidated expert opinions is capable of causing unfair prejudice. That is because, as already noted, the complaint on appeal concerning an alleged lack of validation of TrueAllele (and other matters said to show a lack of qualifications or knowledge on the part of Dr Perlin) was only directed to s 79. It follows from Honeysett, Tuite and Chen that complaint must be rejected.

46. [302]

    For the sake of completeness, we do not accept the premise of this aspect of the appellant’s contention about Dr Perlin’s qualifications, namely, that the lack of a specific validation study addressing four related contributors and related non‑donors raised any issue about Dr Perlin’s ability to express opinions about shadowing or the other opinions he proffered in his evidence at the 2016 trial. It is one thing to say that a system such as TrueAllele must be independently validated before the outputs, and Dr Perlin’s opinions about them, could be described as “reliable”. It is another to say that, for them to be so characterised, there must be a validation study that addresses or encompasses the precise or even a closely analogous set of circumstances to those before the Court, as the appellant effectively contended. As explained, there were a number of validation studies that looked at four or more contributors, there were studies that looked at relatedness of non‑donors in the context of four contributor samples and studies that looked at related donors. The concept of “shadowing” clearly emerged from these studies. Dr Perlin was able to explain how the data obtained from those studies informed his opinions on shadowing in this case, especially so far as Brenda Lin was concerned. Even if the approach in Tuite of “focus[sing] [on] proof of validation” as the touchstone of reliability somehow prevailed in relation to s 79, then it was satisfied in this case.

47. [303]

    As noted, a number of the complaints on appeal asserted that Dr Perlin misrepresented the effect of the validation studies. Hence, in support of Ground 2 it was submitted that Dr Perlin incorrectly told the jury that the December 2013 New York Addendum was “a validation study independent of Cybergenetics of over three or four contributors where kinship was specifically addressed”. [624] That was the description given by Exhibit GD to that report. It was and is a correct characterisation of its effect. Otherwise, we note that these descriptions were given at the 2016 trial. That was more than two years after the voir dire where the December 2013 New York Addendum was tendered.

48. [304]

    In support of Ground 3, it was submitted that Dr Perlin failed “to explain”, or presumably the Crown failed to elicit, “that the studies of relatives of donors producing inclusionary match statistics for a mixture are very limited, and have not progressed beyond two related contributors in a mixture, and even then high inclusionary statistics for non‑donor relatives have been seen”. [625] It follows from the above that this is not an accurate characterisation of the effect of the studies. Otherwise, no such obligation was imposed on either the Crown or Dr Perlin.

49. [305]

    The appellant’s written submissions in relation to Ground 3 also submitted that there was a “failing” (on the part of Dr Perlin) occasioning a miscarriage of justice “[i]n stating that TrueAllele had been independently validated for four related individuals”. It was submitted that was not true and the “only study which looked at a mixture of four related individuals was the [M]aster's thesis”, which was said not to be independent and did not address “whether non‑contributing relatives to the mixtures would also produce inclusionary match statistics”. [626]

50. [306]

    The difficulty with this contention is that neither the Crown nor Dr Perlin asserted that “TrueAllele had been independently validated for four related individuals”. Instead, in cross‑examination at the 2016 trial Dr Perlin rejected a suggestion that TrueAllele “had not been validated … in respect of complex mixed samples involving related individuals in respect of contributors more than three in number”. [627] Exhibit GD identified papers that addressed the topic of “[a]llele overlap with three or more contributors” and “mixed contributors with more than three contributors and up to five contributors where kinship specifically addressed”. It follows from the above, that neither Dr Perlin’s answer nor the description of the various papers in Exhibit GD was incorrect, save for the reference to the Australian Validation Report which only concerned three contributors (although by the time of the 2016 trial TrueAllele had been validated for four contributors). Otherwise, Exhibit GD did not assert that the Master’s Thesis was “independent”. Instead, it said the December 2013 New York Addendum and the Greenspoon paper were. That statement was also correct.

Prosecutor’s Fallacy

1. [307]

   The so‑called “prosecutor’s fallacy” is a fallacious mode of reasoning that transposes the conditional in a likelihood ratio. It is sometimes uttered by expert witnesses, adopted by prosecutors in their closing address or revealed by a summing up (see Galli at [84] per Spigelman CJ). In R v GK [2001] NSWCCA 413; (2001) 125 A Crim R 315 at [48] (“GK”), Mason P referred to a passage from Doheny and Adams [1997] 1 Cr App R 369 at 372 to 373 (“Doheny and Adams”) where Phillips LJ gave, as an example of the fallacy, the treatment of evidence to the effect that a DNA sample from the victim or crime scene which matches the accused and which “[o]nly one person in a million will have a DNA profile which matches that of the crime stain” as demonstrating that “there is a million to one probability that the defendant left the crime stain and is guilty of the crime”. His Lordship observed that the fallacious nature of that statement becomes clear when it is appreciated that the statement that one person in a million has the DNA profile which matches that obtained from the crime scene means that the suspect will be 1 of perhaps 26 men in the United Kingdom who share that characteristic (presumably assuming a population of 52 million with an equal division in gender) (at 373B). Hence, based on those figures alone, the odds of its being the accused are not a million to one. The prosecutor’s fallacy has a defence counterpart which ignores the statistical significance of the other evidence connecting the accused to the crime (GK at [51]).

2. [308]

   Writing extrajudicially, Hodgson JA explained the significance of the prosecutor’s fallacy to Bayes’ Theorem as being that it involved reasoning that ignores the significance of the “prior odds” of the accused being the perpetrator, that is the potentially low odds of the accused being the perpetrator prior to having knowledge of the DNA analysis. [628]

3. [309]

   In the immediate years after GK, this Court dealt with at least two instances where the fallacy found its way into a either a Crown address or a summing up or both. In R v Keir [2002] NSWCCA 30; (2002) 127 A Crim R 198 (“Keir”) a DNA expert testified that it was “approximately 660,000 times more likely” that a DNA profile extracted from bone fragment was from a child of two parents of the victim than “from a child of a random mating in the Australia population” (at [14]). Both the Crown Prosecutor and the trial judge fell into the prosecutor’s fallacy by telling the jury that “there is a 660,000 to one chance that those are the bones of the [victim] as distinct from any other person” (Keir at [16] to [18] and [32]).

4. [310]

   In R v Robinson [2003] NSWCCA 188 (“Robinson”), a DNA expert told the jury that it was “approximately a million times more likely” that blood found on the appellant’s shoes “came from [the deceased] and unknown [man rather] than from two unknown individuals” (at [60]). This Court found that an instance of the prosecutor’s fallacy was revealed in a summing up that transposed the conditional by contending that the effect of the DNA evidence was that “the chances of it [being blood on the shoe] being two random people”, rather than the deceased, was a million to one against and “[i]t was a million times more likely that the deceased was one of the contributors to the DNA on the shoe [of the appellant ]” (Robinson at [190]).

5. [311]

   The necessity to guard against the adoption of the fallacy still pertains today, however it is also necessary to bear in mind the advances in DNA analysis since GK that have, in some instances, led to extremely high levels of correlation between an accused or victim’s DNA and a reference sample. This can be illustrated by considering the following evidence‑in‑chief that was proffered from a DNA expert in the trial that lead to the guilty verdict in the appeal in Doheny and Adams (at 378):

6. [312]

   In Doheny and Adams, Phillips LJ said of these questions and answers (at 378):

7. [313]

   Three matters should be noted about the analysis of the third question in Doheny and Adams, that is evidence purporting to identify the relevant accused or victim as a contributor to the DNA sample.

8. [314]

   First, the statement that an answer to the third question is “one for the jury, not” for the expert is suggestive of an application of the ultimate issue rule which has been abolished in this State (Evidence Act, s 80) and does not apply in criminal proceedings in the United Kingdom (R v Atkins (2009) EWCA Crim 1876 at [17]; R v Gardner [2004] EWCA Crim 1639 at [43]).

9. [315]

   Second, the difficulty identified by Phillips LJ in Doheny and Adams with the third answer was that, given the size of the likelihood ratio in that case, it followed that the possibility existed of a “handful of other persons” in the United Kingdom who might also have a DNA identity that matched the DNA profile of the assailant.

10. [316]

    However, as noted, DNA analysis has advanced since Doheny and Adams and GK were decided. A number of the tests involve an analysis of more loci than those considered at the time of GK and Doheny and Adams (see [92]). Such analysis often yields extremely high likelihood ratios that vastly exceed the Earth’s population. With such ratios it may no longer be correct to say that there could be a number of people in this country, or even on Earth, with a DNA profile that matches the reference sample of the accused person or victim. In terms of Bayes’ Theorem, even if the prior odds were very small, the posterior odds may still be very large. In Doheny and Adams Phillips LJ recognised the possibility of advances of DNA analysis in observing that there may be a time where a “match will be so comprehensive that it will be possible to construct a DNA profile that is unique and which proves the guilt of the defendant without any other evidence” (at 373G). Further, in describing the effect of the prosecutor’s fallacy, Phillips LJ observed that “[t]he more remote the random occurrence ratio, the less significant will be the adoption of the ‘[p]rosecutor’s [f]allacy’, until the point is reached where that fallacy does not significantly misrepresent the import of the DNA evidence” (at 379A; see also Galli at [115] to [117] per Spigelman CJ). That position was said to be reached in Doheny and Adams with a random occurrence ratio of 1 in 40 million testified to in that case (at 379A and 378B), although the evidence supporting that figure was successfully challenged on other grounds.

11. [317]

    Third, regardless of the size of the match statistic or likelihood ratio, there is no all-embracing rule precluding an expert from answering questions of the third kind noted in the above extract. One difficulty for a DNA analyst in answering the third question based on a likelihood ratio in the thousands or tens of thousands in this country is that the population of this country exceeds 25 million so that it is possible that there are other persons who could provide a match to the sample like the accused. Another potential difficulty is the existence of a closely related person or persons to the accused or victim such that a match statistic expressed by reference to an unrelated person is not the same as a statistic expressed by reference to a related person. Thus, in some cases a DNA analyst who purported to answer the third question might have deployed an assessment of their knowledge of the other evidence in the case which might connect the accused to the crime or the victim to the accused. In such cases it may be that an opinion of the kind given in answer to the third question above would not be wholly or substantially based on the witness’ specialised knowledge but instead based on their subjective assessment of that other evidence (Honeysett supra). Whether that is so will depend on the case and depend on the expert, especially their proffered chain of reasoning as that may or may not demonstrate that their opinion is in fact wholly or substantially based on their specialised knowledge. In this case, one of the complaints under this heading about Dr Perlin’s evidence is that at various points in his evidence he proffered what the appellant identified as identification evidence in that he stated it was extremely unlikely that the DNA of the victims was not present in Stain 91. These instances are addressed below but it suffices to state that, to the extent he did, the opinions he expressed were within his expertise and he explained how that was so.

12. [318]

    Accordingly, it does not necessarily follow that an expert DNA witness does not have specialised knowledge to answer the third question in the above extract assuming that the reference to “it is he” is a reference to the evidentiary sample taken from a scene being (or including) the accused’s DNA. As stated, whether they have the specialised knowledge to do so will depend on the case, depend on the expert and depend on the reasoning that accompanies the opinion. Of course it would not necessarily extend to the expert witness positing that the accused is the rapist, murderer or attacker or that the sample definitely comes from the accused or victim as the case may be given the possibilities consistent with innocence that may exist as to how the accused’s or victim’s DNA came to be present in the relevant sample such as transference or contamination. Otherwise, there exists the various discretions in the Evidence Act to exclude such evidence and their exercise will at least in part depend on the “elucidation and explanation” that accompanies the relevant figures (Aytugrul v R (2012) 247 CLR 170; [2012] HCA 15 at [32]).

13. [319]

    Since 2011, Professor Gill has been a Professor of Forensic Genetics at Oslo University Hospital and the University of Oslo, Norway. He has a degree in zoology and a PHD in genetics and zoology. His curriculum vitae discloses that he has extensive experience in the field of DNA extraction and interpretation, including analysis of complex DNA mixtures. He has published extensively and has given evidence in a number of significant cases involving DNA evidence, including Doheny and Adams. His curriculum vitae does not disclose that he has any particular qualifications in mathematics or statistics although, given his area of expertise, it is to be expected that he would have considerable knowledge of statistical methods.

14. [320]

    At the hearing of the appeal, the Crown did not require Professor Gill for cross‑examination on his report. Instead, it made submissions based on the apparent limits of Professor Gill’s instructions, the absence of his engagement with the substance of Dr Perlin’s reasoning and what was said to be his lack of qualifications so far as statistical methods are concerned. With the last matter, the Crown objected to parts of Professor Gill’s report on the basis that he lacks specialised knowledge to proffer the opinions he does. [629]

15. [321]

    Broadly, Professor Gill’s appeal report addressed two topics, the first being the supposedly correct and only form in which DNA evidence should be reported and the second being the prosecutor’s fallacy. In relation to the former, Professor Gill said he relied heavily on two publications by the International Society of Forensic Genetics DNA Commission (“ISFGDNA”), a body which he participates in. Professor Gill stated that those publications describe “the correct use of the likelihood ratio formulas” and “provid[e] advice on how scientists should report evidence to courts”. [630] Based on the recommendations of the ISFGDNA, Professor Gill opined that a likelihood ratio expressing the probability of the evidence given the prosecution hypothesis, divided by the probability of the evidence given the defence hypothesis, “forms the foundation of reporting evidence to courts”. [631] To that end, he specified that there was a “requirement” for each of the prosecution and defence hypothesis to be formulated “through dialogue between parties in the criminal justice system”. [632] Further, Professor Gill also rejected any suggestion that the “scientist” could opine on identity, stating that a scientist “is not allowed to use statements like: ‘He/she is or is not in the mix’”. [633] He described that as an instance of the prosecutor’s fallacy.

16. [322]

    In relation to the prosecutor’s fallacy, Professor Gill contended that the likelihood ratios were altered when issues of relatedness arose and this illustrated the difficulty in moving from an apparently high likelihood ratio to asserting that the relevant reference sample forms part of the DNA mixture. [634] In section 9 of his report he identified five statements of Dr Perlin as evincing the prosecutor’s fallacy, specifically the evidence of Dr Perlin noted in [145], [147] and [150] in relation to Min, Terry and Henry Lin where he referred to the inversion of the match statistic as the upper limit on the probability of achieving a match statistic that high if their DNA was not present in Stain 91, his evidence reporting on Irene Lin’s match statistic [635] and his evidence about the possibility of neither Irene nor Lily Lin’s DNA being present in the sample (see [155]). [636]

17. [323]

    At this point three related aspects of Professor Gill’s report should be noted.

18. [324]

    First, as noted Professor Gill’s report starts from the premise that the ISFGDNA’s guidelines are determinative of the manner and form in which such opinion evidence must be given. It suffices to state that those guidelines do not have that status. This Court reviews the evidence that was given at the trial having regard to the Evidence Act and a consideration of whether some aspect of the evidence rendered the trial unfair.

19. [325]

    Although it was not expressly taken up in the appellant’s submissions, it seems that Professor Gill does not accept the form of the match statistics reported by Dr Perlin to the jury at the 2016 trial. Dr Perlin expressed the match statistic as a figure specifying that a match between Stain 91 and a reference sample was so many more times more probable than a coincidental match to an unrelated Asian person (with a similar figure for a caucasian person). [637] In his May 2020 report, Dr Perlin addressed Professor Gill’s views on match statistics in some detail. He expressed in mathematical form the various permutations of a likelihood ratio and a match statistic to show how they were the same number algebraically. [638] He provided a report to the same effect during the voir dire. [639] He told the jury at the 2016 trial that they were the same number. [640]

20. [326]

    A review of some of the cases reveals that there is no uniform manner of expressing statistical DNA evidence. Sometimes the evidence is given as a frequency ratio which specifies that one in a specified number of persons would have a matching DNA profile which is accompanied by an exclusion percentage being the amount of the population which does not have that profile (see Aytugrul at [9]). However, the evidence given by the DNA experts in Robinson and Keir, which was not impugned, was given in the same form as that given by Dr Perlin in this case.

21. [327]

    We do not accept that there was anything misleading or prejudicial in the form of the match statistic that Dr Perlin provided to the jury. This conclusion is sufficient to address one of the alleged instances of the prosecutor’s fallacy identified by Professor Gill. Professor Gill asserted that Dr Perlin stated, “[b]y reference to a coincidental match to an unrelated Asian person, a match between the garage floor and Yun Bin (Irene) Lin was 28.5 thousand times more probable, when three contributors were assumed”. [641] Dr Perlin did not give that evidence. Instead, he said that “a match between the garage floor and Irene is 28.5 thousand times more probable than a coincidental match to an unrelated Asian person”. [642] That evidence was consistent with the form of match statistics that Dr Perlin provided in the balance of his evidence.

22. [328]

    Second, it appears that there are significant limitations on the instructions that Professor Gill was provided about the defence case and the course of the trial which are material to the opinions he expresses. These are apparent when one considers the section of Professor Gill’s report directed to Dr Perlin’s evidence about Brenda Lin and shadowing. At one point he describes the defence case as being that the contributor’s DNA was transferred “innocently, either by direct or indirect means” and noted that “Terry and Henry Lin used to play in the garage”. [643] This appears to convey an understanding that the defence case involved at least an acceptance that Terry and Henry Lin’s DNA were present in Stain 91. However, later in the same section of the report he notes that Dr Perlin gave evidence that it was “10 million times more likely that Min is in there than Brenda” with a similar figure for Terry Lin. [644] Professor Gill was critical of this. He said it assumed that the denominator for Min Lin and Brenda Lin’s match statistics was the same and, inter alia, takes “no account of the defence alternative who clearly dispute the presence of Terry and Min in item 550”. [645] In relation to the denominator, in the May 2020 report Dr Perlin confirms they were the same. [646] As for the “defence alternative”, Professor Gill appears earlier to have appreciated that the defence at least accepted the presence of Terry Lin’s DNA in Stain 91. In any event, Professor Gill’s characterisation of the “defence alternative” is very much incorrect. As noted, at the 2016 trial the defence accepted the presence of Min, Terry and Henry Lin’s DNA in Stain 91.

23. [329]

    At the conclusion of his report Professor Gill posited that the “defence must be able to participate in the formulation of their propositions” and “[i]t is not appropriate for the exercise to be dominated solely from the prosecution perspective”. [647] He opined that the defence was “entitled to request likelihood ratios that are based on assumptions of both unrelated and related individuals” and that “[n]ot all known related individuals were analysed by TrueAllele as persons of interest”. [648] These statements seem to imply, or at least assume, that the defence were excluded from formulating scenarios for Dr Perlin and TrueAllele to consider. In fact, it was the defence who suggested that Brenda Lin’s DNA be used as a reference sample for TrueAllele and Dr Perlin produced a report that addressed that. [649] At no stage prior to the 2016 trial did the defence request that other relatives be used by TrueAllele as a reference sample. In any event, Mr Walton addressed the position of the other relatives.

24. [330]

    Third, as noted, the principal objection that Professor Gill raised to relying on very high match statistics expressed by reference to a comparison to unrelated persons as a basis for opining that a particular reference sample was the contributor or was extremely likely to be the contributor concerned the question of relatedness. He contended that it overlooked the position of other possible related contributors. In his report prepared for this appeal, Dr Perlin stated this concern was misplaced. [650] He stated that he addressed the question of a potential related donor by his evidence about shadowing and Brenda Lin at the 2016 trial and, as just noted, the competing chances of the various relatives being contributors can be quantitatively assessed by dividing their respective match statistics (which have a common denominator that cancel out). [651]

25. [331]

    The appellant’s written submissions contended that, at various times in his evidence, Dr Perlin purported to express an opinion that at least Terry, Henry and Min Lin’s DNA was present in Stain 91 and in doing so he committed the prosecutor’s fallacy. [652] The appellant contended that the cases demonstrate an “insistence in orthodox cases that experts do not express an opinion that the DNA was left [or originated] from a particular person” and that Dr Perlin’s evidence “indicating that individual people did contribute or almost certainly contributed, or had extremely strong statistical support for having contributed was impermissible”. [653]

26. [332]

    The written submissions appeared to tie aspects of this complaint to the suggestion that there were vast numbers of superior matching genotypes that were ignored. [654] The oral submissions appeared to tie this complaint to its contentions about Dr Perlin’s evidence about false positives. [655] Both of those complaints have been rejected. Further, it follows from the above that we do not accept that the cases have the effect the appellant contends.

27. [333]

    As for the balance of the complaint, the overall effect of the evidence given by Dr Perlin in relation to Min, Terry and Henry Lin was that there was a high probability of an evidential match as opposed to him purporting to definitively state that a particular victim’s DNA was present in Stain 91. Hence, the match statistics he provided in his oral evidence were expressed as a probability. [656] Dr Perlin agreed with questions to the effect that that the match statistics provided “strong statistical support” for the victim’s presence. [657] It is true that some slides used the heading “[i]s the victim in the evidence?”. [658] However, that was a reference to the issue posed for the jury. The same slide provided an answer in the form of a match statistic rather than “yes” or “no”. Further, the references to Henry Lin being “in together with Terry’s genotype” was a reference to the inferred contributor that was the source of the relevant match statistic. [659] The Crown Prosecutor’s address to the jury suggested that Dr Perlin’s evidence provided strong statistical support for the conclusion that the Min, Terry, Henry and Irene Lin’s DNA was present in Stain 91 which they should find. However, the Crown Prosecutor did not suggest that Dr Perlin actually said that in his evidence. The trial judge told the jury that the match statistics “provided very strong statistical support for Min and his two sons being in the mix”. [660]

28. [334]

    In any event, consistent with the above analysis there was nothing impermissible in relation to Dr Perlin suggesting that their very high match statistics were close to or at a point where it confirmed the presence of Min, Terry and Henry Lin’s DNA in Stain 91. Even if there was, it would not be productive of a miscarriage of justice in circumstances where it only concerned a fact that was already agreed. As for his evidence concerning Irene and Lily Lin, it is addressed below.

29. [335]

    The other basis on which the appellant contended that Dr Perlin committed the prosecutor’s fallacy, concerns the statistics that Dr Perlin stated were the likelihood of achieving the relevant match statistic for a particular reference sample but that person’s DNA not being present in Stain 91. [661] Hence, in relation to the evidence that Dr Perlin provided concerning Terry Lin set out at [145], it was contended that his evidence that “it would be extremely unlikely, in fact, a chance of less than 1 in 10 trillion, that he wouldn’t be present” involved in an inversion of the likelihood ratio and “dropping the conditional”. [662] Similar complaint was made concerning the figures provided for Henry Lin (“getting a number this large, would be less than 1 in a billion; actually less than 1 in 2 billion”) [663] and Min Lin (“I would say that the chance of having a match statistic this high, but Min not being present is in the order of 1 in a billion”). [664] As noted, Professor Gill also nominated these aspects of Dr Perlin’s answers as revealing an application of the prosecutor’s fallacy. [665]

30. [336]

    It is important to note exactly how this evidence was framed. In his evidence at the 2016 trial, Dr Perlin phrased these statistics as representing the likelihood that a person who was (definitely) not a contributor would nevertheless produce a match statistic as high as that produced by the reference sample (“the chance of having a match statistic this high, but Min not being present”). He also stated that one over the match statistic represented the upper bound of that probability (“it's 1 over the match statistic”).

31. [337]

    Dr Perlin addressed this in his report dated 19 May 2020 (ie, his appeal report), stating as follows: [666]

32. [338]

    In the balance of his report, Dr Perlin states that using his non-contributor analysis it was possible to compute “false positive match error rates” as opposed to just specifying an upper bound as he did in his evidence at the 2016 trial. [667] For example, for Terry Lin with a match strength of 50.4 quadrillion Dr Perlin calculated that “only 1 in 143 quintillion people would match as strongly”, [668] for Henry Lin for a match strength of 2.21 billion “only 1 in 13.7 trillion people would match as strongly”, [669] for Min Lin using a match strength of 226 thousand “only 1 in 4.21 billion people would match as strongly”, [670] for Irene Lin using a match strength of 28.5 thousand, “only 1 in 366 thousand would match as strongly” [671] and for Lily Lin with a match strength of 289 “only 1 in 18.3 thousand people would match as strongly”. [672] The calculation of error rates below the upper bound was addressed by Hodgson JA in the article cited above. [673]

33. [339]

    In his oral evidence on the appeal, Dr Perlin emphatically restated the correctness of using the inverse of the match statistic as the upper bound on the error rate. [674] Towards the end of his cross‑examination in this Court, he was asked: [675]

34. [340]

    The reference to the “more refined calculation” was to the figures in his report dated 19 May 2020 provided on appeal noted above. Later in his evidence Dr Perlin re‑iterated that the inverse of the match statistics was the upper bound of the error rate, specifically that it measured “[h]ow often we would be seeing this strength of evidence, if somebody hadn’t actually left their DNA”. [676] Dr Perlin also agreed that the calculations of the error rate he provided on appeal did not take account of relatedness. [677] He was not asked whether the upper bound of the inverse of the match statistic was affected by relatedness.

35. [341]

    Beyond this, Dr Perlin was not pressed in cross‑examination on the issue. In particular, he was not taken to the articles he cited in support of the above statements. Other than his reference to relatedness, Professor Gill did not expand upon his objections to Dr Perlin’s evidence on this topic at the 2016 trial either, assuming that he was qualified to do so. An expert in statistical methods could have addressed this topic but, leaving aside Dr Perlin who has extensive mathematical qualifications, no such evidence was adduced.

36. [342]

    As best as we can ascertain the reference to the upper bound being the inverse of the match statistic appears to be an application of the so called “universal bound” in statistics whereby the probability of observing misleading evidence of k-strength is always bounded by 1/k (see the article cited by Dr Perlin, namely, R Royall, “On the probability of observing misleading evidence” (2000) 95 (451) J AM Stat Association 760 at 763; and Hodgson supra at 114 and 115). However, it is not necessary or even possible to consider this further. It is not self-evident that any of this evidence of Dr Perlin invokes any aspect of the prosecutor’s fallacy as discussed in the cases or any other form of fallacy, or that it has been shown that this evidence was inadmissible even if it had been objected to. The only issue raised in respect of this evidence concerns relatedness but this was not developed. Even if the inverse ratios that Dr Perlin provided to the jury at the 2016 trial needed to be qualified to accommodate related donors or non-donors, the combination of Mr Walton and Dr Perlin’s evidence was that, so far as the major component and Terry, Henry and Min Lin were concerned the only possible relative to consider was Brenda Lin. [678] Dr Perlin addressed her position extensively and in a manner that did not involve any form of prosecutor’s fallacy. (Mr Walton had excluded Kathy Lin and XX as contributors to the major component. [679] )

37. [343]

    It can be accepted that considerable caution needs to be exercised before evidence expressed in the above form should be allowed to be adduced in other cases. However, what is critical in this case is that this evidence concerns facts that were not in issue at the 2016 trial, namely, whether Min, Terry or Henry Lin’s DNA was present in Stain 91. In the absence of any issue being taken about this aspect of Dr Perlin’s evidence at the 2016 trial, and given that it concerned an agreed fact, it was not demonstrated that some miscarriage of justice was occasioned by this aspect of Dr Perlin’s evidence.

38. [344]

    The appellant’s written submissions also cited the evidence given by Dr Perlin when he was asked “there's no possibility is there, on the work done by the computer that neither of them [ie, Irene and Lily Lin] are there” and responded “[n]o, not based on what I'm seeing”. [680] Professor Gill also referred to that evidence in his report as an instance of the prosecutor’s fallacy. [681] Unlike Dr Perlin’s evidence in relation to Min, Terry and Henry Lin, in his evidence at the 2016 trial Dr Perlin did not refer to the inverse of the match ratio as the upper bound of the probability of having a match statistic as high as Irene or Lily Lin but nether being present. Instead, the evidence he gave was referable to the empirical analysis of error rates that he cited and a discussion of the possibility of shadowing between them as well as a comparison with Brenda Lin. The limits of his opinion so far as Kathy Lin was concerned was made clear to the jury. [682] It has not been shown that this aspect of Dr Perlin’s evidence was fallacious or was otherwise productive of a miscarriage of justice.

Ground 1 - Johnson J erred in admitting the evidence of Dr Perlin

1. [345]

   As noted, Ground 1 of the appeal contends that in Xie (No 4) Johnson J “erred in admitting the evidence of Dr Perlin”.

2. [346]

   The appellant contended that the evidence adduced at the 2016 trial was “substantially more expansive” than the evidence the subject of the ruling by Johnson J in Xie (No 4). [683] Although this complaint appears to be directed to Ground 3 of the appeal, it is appropriate to address it at this point. The appellant contended that his Honour’s ruling did not extend to any evidence that Dr Perlin might give on the meaning of the match statistics, including shadowing, [684] and did not extend to Dr Perlin advising the jury of match statistics calculated by TrueAllele on the basis that there were more than three contributors to Stain 91. [685]

3. [347]

   Xie (No 4) addressed a notice of motion filed by the appellant in November 2013 which, inter alia, had sought the exclusion of “evidence of DNA analysis relating to [Stain 91] to be given by Mr Clayton Walton, Mr Robert Goetz, Ms Sharone Neville, Dr Simon Walsh and Dr Mark Perlin”. [686] A schedule to the notice of motion identified an objection to the “report and accompanying documents of Dr Perlin dated 23 September 2013”. That report and an accompanying witness statement set out match statistics for each of the victims and various stains, including Stain 91, calculated on the assumption of three contributors. [687] As already noted, during the voir dire a “case packet” was produced which included match statistics for runs of more than three contributors. [688]

4. [348]

   During the voir dire on 26 March 2014, the Crown Prosecutor advised that Dr Perlin had completed an updated report dated 21 March 2014 to account for a revised theta co‑ancestry coefficient [689] as well as a revised slide presentation and case packet. [690] The revised slides are the same as those that were presented to the fourth jury. [691] The supplemental case packet included tables of match statistics for various TrueAllele runs that assumed three, four or five contributors and used the DNA data from the Profiler Plus, Identifiler and PowerPlex 21 DNA kits. [692] The table for PowerPlex 21 is Annexure 1. All of those documents were sought to be tendered on the voir dire. Senior Counsel for the appellant told the Court that he objected to the tender. [693]

5. [349]

   As noted above, [694] Dr Perlin first referred to the phrase “shadowing” in his evidence on 18 March 2014 when explaining the December 2013 New York Addendum and that was prior to any issue arising concerning the possible presence of Brenda Lin’s DNA in Stain 91. [695] Otherwise, in his oral evidence on the voir dire, Dr Perlin addressed a contention that he “cherry picked” results by explaining his process of comparing results including, inter alia, match statistics derived from runs of TrueAllele that assumed different numbers of contributors. [696]

6. [350]

   On 27 March 2014, the Crown Prosecutor tendered a further report from Dr Perlin dated 26 March 2014. This report responded to a defence request to examine whether Brenda Lin’s DNA contributed to the DNA in Stain 91. [697] That report was also objected to by Senior Counsel for the appellant. [698] This report was divided into three parts. The first part identified positive match statistics for Brenda Lin and four DNA stains, one of which was Stain 91. It posited that “some of these positive values may be due to false positive ‘shadowing’ from related individuals”. [699] Part 2 stated that it sought to address that issue and noted that for, inter alia, Stain 91, Brenda Lin’s match statistic could be a false positive “due to ‘shadowing’ from relatives”. This part of the report suggested that a “more refined analysis assuming five individuals could provide more information as to whether Brenda [Lin] contributed her DNA to the evidence items”. [700] Part 3 of the report outlined a process of assuming five contributors and then successively running TrueAllele by assuming that each “strongly matching individual” contributed to the sample. The result was that either Irene or Lily Lin may be a “possible contributor”, but “Brenda’s negative log(LR) match value provides no statistical support for her having contributed her DNA to the mixture”. [701] This was known as the “peeling analysis”.

7. [351]

   After some questioning of Dr Perlin on the report, the Crown Prosecutor confirmed that the tender of so much of the report that concerned “peeling” was not pressed. [702] However, the Crown did not disavow the balance of the report. Instead, the Crown Prosecutor directed questions as to the effect of Dr Perlin’s opinion about the presence of Brenda Lin’s DNA in Stain 91 if Part 3 was excluded. [703] Dr Perlin expressed the opinion in relation to Stain 91 and two other stains that “Brenda’s positive match statistics could be false positives due to shadowing from relatives”. [704] Senior Counsel for the appellant then cross‑examined Dr Perlin about “shadowing”. [705]

8. [352]

   In Xie (No 4), Johnson J addressed a complaint that adducing DNA evidence, including Stain 91 and match statistics derived from TrueAllele, would be “misleading or confusing” within the meaning of s 135(b) of the Evidence Act. His Honour noted that the “LR evidence resulting from the TrueAllele process will be a topic for explanation and assistance during evidence”. [706] His Honour also noted that the “evidence will be given in the manner foreshadowed during Dr Perlin’s evidence at the pre‑trial hearing”. [707]

9. [353]

   The ultimate ruling of his Honour in Xie (No 4) was, relevantly, that “[t]he evidence concerning the location, examination and testing of Stain 91 and subsequent DNA analysis, including LR opinion evidence is relevant and admissible under s 55 Evidence Act 1995, and I decline to exclude it under ss 135 or 137 Evidence Act 1995”. [708] Given the width of that ruling, the references in Xie (No 4) to adducing at the trial the evidence given by Dr Perlin on the voir dire and the content of that evidence, it follows that his Honour’s ruling clearly extended to Dr Perlin’s opinions on the meaning of the match statistics, the basis for reporting the match statistics and, to the extent that it may arise, shadowing between relatives. Given that the Crown Prosecutor did not press the tender of Part 3 of Dr Perlin’s report dated 26 March 2014, it also follows that the ruling did not extend to any evidence of the peeling analysis.

10. [354]

    As for whether the ruling in Xie (No 4) extended to Dr Perlin reporting, or even referring to, the results derived by TrueAllele from assuming four or five contributors, in Xie (No 4) Johnson J twice referred to the fact that runs based on four and five contributors were undertaken. [709] As noted, Dr Perlin gave oral evidence explaining how those results for four or five contributors supported the results for three contributors that were set out in the slide presentation. [710] Also as noted, Johnson J specifically contemplated that “it is to be expected that the evidence will be given in the manner foreshadowed during Dr Perlin’s evidence at the pre trial hearing”, which clearly extended to discussing the results for four and five contributor runs. Again, given that statement and the breadth of the ruling, it is clear that the ruling in Xie (No 4) also extended to permit the Crown to lead evidence from Dr Perlin concerning the match statistics for TrueAllele runs involving more than three contributors.

11. [355]

    In Xie (No 4), Johnson J did not address any objection based on s 79 of the Evidence Act. It was accepted in this Court that no objection to Dr Perlin’s evidence based on that section was ultimately pressed before his Honour. [711] In relation to ss 135 and 137, his Honour found that the probative value of “Stain 91 and [the] DNA evidence”, which included Dr Perlin’s evidence, was “substantial”. [712] His Honour rejected any suggestion of prejudice arising from its admission or that it might be “misleading” or “confusing” on the basis of, inter alia, its complexity, [713] the alleged lack of validation of TrueAllele, [714] its supposed status as “a work in progress”, [715] the fact that it may necessitate a substantial defence case [716] or the possible existence of “contrary or alternative approaches to [the] statistical evidence”. [717]

12. [356]

    The appellant’s written submissions in relation to Ground 1 contend that Johnson J “mistook the facts, and failed to take into account some material considerations”. [718] Each of the specific matters referred to are addressed below. The appellant’s submissions further contend that those errors occurred “because, although the relevant material was before his Honour, it was not explained clearly by Dr Perlin or by the party seeking to adduce his evidence, the Crown”. This was said to have caused his Honour to not “understand how the expertise [of an expert such as Dr Perlin] is brought to bear on the opinions expressed, and the limitations of the opinion evidence”. The next part of the submissions address the limits on Dr Perlin’s expertise and set out various matters that were said to be necessary to enable the evidence that was adduced to be understood.

13. [357]

    It is not clear how a contention that supposedly explains why Johnson J allegedly erred in Xie (No 4) by “mist[aking] the facts, and fail[ing] to take into account some material considerations” advances the complaint of error. Nevertheless, these submissions will be addressed because in their own right they appear to raise matters that may be capable of undermining Johnson J’s findings in respect of probative value, prejudice and the potential for the evidence to be “misleading” or “confusing”.

14. [358]

    In relation to Dr Perlin’s expertise, the appellant’s submissions accept that Dr Perlin had some “specialised knowledge”, but only knowledge that “allowed him to express a very specific opinion … namely how much more probable a match between a reference sample (say of each deceased in this case) and a particular inferred genotype from a mixture is, than a coincidental match between that particular inferred genotype and an unrelated Asian person”. [719] It was contended that Dr Perlin was only qualified to describe that result by reference to the specific TrueAllele run and weight contributor that it was referable to. [720]

15. [359]

    Even though this submission is directed to a complaint of error on the part of Johnson J, it bears no resemblance to the manner in which the voir dire before Johnson J was conducted. As noted, no issue was taken under s 79 on behalf of the appellant in relation to Dr Perlin’s specialised knowledge and, in particular, no submission was made that Dr Perlin’s expertise was limited such that he could only convey to the jury the match statistics calculated by TrueAllele for each run. As already noted, Johnson J addressed a complaint that to simply convey those statistics would be misleading by pointing to the explanation that would accompany them from Dr Perlin. In any event, the complaint of a lack of “specialised knowledge” on the part of Dr Perlin to convey anything more than the results of TrueAllele is rejected for the reasons given above. [721]

16. [360]

    The appellant’s written submissions also contended that “[i]t should have been made clear to [Johnson J] by Dr Perlin and the Crown that” certain further information “would necessarily be required to be presented for the above match statistics to be accurately understood” by the jury. [722] This contention will be addressed as though it contended that the absence of any consideration by Johnson J of the supposed necessity to convey the relevant information to the jury, potentially undermined his Honour’s assessment of probative value, prejudice or the potential for the evidence to be “misleading” or “confusing”.

17. [361]

    The first item of information that it is said should have been made clear to Johnson J as having been required to be provided to the jury was “the fact that multiple relatives produced a statistic that would normally be regarded as inclusionary, for the same inferred genotype, is a reflection of the uncertainty of the data”. [723] This is addressed above. [724] The degree of uncertainty is quantified by the match statistic.

18. [362]

    The second item of information that it is said should have been made clear to Johnson J as having been required to be provided to the jury was that inclusionary match statistics for multiple relatives referable to the same genotype “mean[s] no more than that each of those relatives could have contributed to each of those three genetic profiles separately considered by the system”. [725] Again, this is addressed above. [726] The premise of the contention is not made out. Inclusionary match statistics for multiple relatives referable to the same genotype have far more meaning than simply stating they “could have contributed” to the sample.

19. [363]

    The third item of information that it is said should have been made clear to Johnson J as having been required to be provided to the jury was that “[i]n relation to each of those three separate contributors there are millions or billions or trillions (as the case may be) other full genetic profiles which have also been inferred by the TrueAllele system as equally or more adequately explaining the uncertain data as the deceased and Brenda Lin”. [727] This is also addressed above. [728] Again, the premise is not made out. The “other full genetic profiles” being referred to do not correspond to real persons.

20. [364]

    The fourth item of information that it is said should have been made clear to Johnson J as having been required to be provided to the jury was that “[o]ther relatives such as Kathy Lin and [XX] have not been assessed for a match statistic by the TrueAllele system”. [729] Under cross‑examination at the 2016 trial, Dr Perlin told the jury that Kathy Lin was not used as a reference sample. [730] He also told them that the appellant had been excluded. Neither the Crown Prosecutor, nor counsel for the appellant, told the jury whether or not XX had been used as a reference sample. Mr Walton told the jury that he had excluded both Kathy Lin and XX as major contributors to Stain 91. He could not exclude them as minor contributors but the evidence suggesting they were was far weaker than that concerning Lily and Irene Lin. [731] In these circumstances, it is not clear why the jury at the 2016 trial had to be expressly told that XX had not been used as a reference sample. Otherwise, the fact that he had not been used did not affect an assessment of the probative value attaching to Dr Perlin’s evidence and the match statistics produced by TrueAllele. The Crown also contended that, given TrueAllele yielded an exclusionary result for the appellant on the basis of his “Y filer” results, then such a result would inevitably have followed for XX. [732] That seems likely but it is not necessary to determine.

21. [365]

    The fifth item of information that it is said should have been made clear to Johnson J as having been required to be provided to the jury was that the “figures cannot be taken as an expression of an opinion that, if there was a 59% contributor of [three], and even if it was one of the three males considered by the system, the true donor was more likely to be Terry Lin than Min Lin or Henry Lin because his match statistic is higher - the relevant study of related mixtures does not allow such simple comparison to be made”. [733] This refers to row 2 of Annexure 1. A similar point was made in relation to the figures in row 1 and row 3, the latter of which concerns match statistics for Lily and Irene Lin. [734] All of these contentions are inconsistent with Dr Perlin’s evidence to the effect that it is not appropriate to concentrate only on a single row of match statistics, but instead report concordant match statistics. As already noted, Dr Perlin gave the jury at the 2016 trial a summary of his approach to reporting match statistics. [735] He addressed the more complex position concerning Lily and Irene Lin in his evidence at the 2016 trial. [736]

22. [366]

    The sixth item of information that it is said should have been made clear to Johnson J as having been required to be provided to the jury was that the “witness [ie, Dr Perlin] does not contend there were in fact three contributors to the mixture”. [737] It is not clear why the jury would have to be expressly told that, given it was made clear to them that TrueAllele only operated upon an assumed number of contributors. In any event, Dr Perlin told the jury that he thought “there are four [contributors and that] based on our statistical analysis, it could be five”. [738] This was consistent with Mr Walton’s evidence. [739]

23. [367]

    The appellant ultimately submitted that “given … the only way they [the match statistics] could be accurately expressed” then “they in effect show no more than that, assuming there were three contributors to [Stain 91], the six individuals tested (the five deceased and Brenda Lin) were much more likely than a coincidental unrelated person to have been one of the three contributors”. It was submitted that this meant the evidence was “not of substantial probative value”. [740] It follows from the above analysis of the various complaints about the evidence that Johnson J was correct to conclude that the match statistics had substantial probative value.

24. [368]

    The appellant further submitted that, in applying ss 135 and 137, Johnson J “mistook the facts, and failed to take in account some material considerations”. [741]

25. [369]

    The relevant “facts” that Johnson J was said to have mistaken were described as follows: [742]

26. [370]

    The first of these complaints concerns Johnson J’s acceptance in Xie (No 4) of a Crown submission which his Honour summarised as follows: [743]

27. [371]

    This submission accurately reflects the evidence concerning the validation studies and the interrelationship between complexity and the calculated match statistic. His Honour did not err in accepting this submission.

28. [372]

    In relation to the second alleged mistaken fact said to have been found by Johnson J noted above, the short answer is that his Honour made no such finding. In Xie (No 4), his Honour addressed this aspect of the evidence concerning Brenda Lin as follows:

29. [373]

    This passage is consistent with the above analysis of the scope of the ruling. It confirms that the Crown did not press for a ruling on evidence about “peeling” (and implicitly that it did press the evidence concerning shadowing, which was allowed). The only passage that equates to the finding that the appellant alleges was made by Johnson J is the passage at the end of Xie (No 4) at [345]. However, in that passage his Honour was only referring to evidence given by Dr Perlin that summarised that part of his supplementary report which addressed “peeling” and in respect of which no ruling was sought. [744] Later in a section of the judgment titled “Decision”, his Honour expressed “broad agreement with the Crown submissions made with respect to these issues”. [745] The “issues” that his Honour referred to were the issues for determination. They did not include any finding about the admissibility of Dr Perlin’s evidence concerning peeling.

30. [374]

    It follows that this contention fails because the impugned finding was not made. To the extent that the submission also concerns the admission of evidence about shadowing and refers to the analysis in “Part D” of the appellant’s written submissions, then it has already been addressed. [746]

31. [375]

    The alleged “material facts” that were not taken into account by his Honour were identified in the appellant’s written submissions as follows: [747]

32. [376]

    The appellant’s submissions concede that the “problems with the proposed match statistics were not clearly articulated this way on behalf of the [appellant] before his Honour”. [748] In fact, they were not articulated at all at first instance. In any event, with the first of these matters the relevant finding in relation to validation studies by Johnson J in Xie (No 4) at [338] is set out above. It follows from the analysis at [257] to [306], that his Honour’s findings were correct. Otherwise, as explained, no point was taken before Johnson J that Dr Perlin did not have the necessary “specialised knowledge” to provide “further elucidation” on the match statistics. To the contrary, the fact that he could and would do so was one of the reasons it was found not to be “misleading” or prejudicial for evidence of the match statistics to be adduced. Further, for the reasons addressed above, Dr Perlin possessed the requisite “specialised knowledge” to provide that elucidation.

33. [377]

    The second and third “material facts” that the appellant contends Johnson J failed to take into account are addressed above. [749] It follows from that analysis that neither of them was or have been established as “facts”, much less “material facts”, or facts that were obliged to be considered by his Honour.

34. [378]

    In oral submissions on the appeal, it was submitted that Johnson J also erred in determining the probative value of Dr Perlin’s evidence and the match statistics produced by TrueAllele. It was submitted that his Honour failed to take into account a concession said to have been made by Dr Perlin on the voir dire that, if the relevant inferred contributor’s inferred genotype is less than 10%, then there are many instances when the true contributor is not detected. [750] This was said to have particular significance where the reported match statistics for Irene and Lily Lin for three contributors of 4.45 and 2.69 respectively concerned an inferred contributor of 7% by weight. [751] It was accepted that no such contention was made to Johnson J even though the voir dire was conducted on the basis that those would be the figures provided to the jury. Further, this Court was not referred to the passage where the apparent concession was made. However, Dr Perlin did state during the voir dire that the “likelihood ratio is ... a summary statistic that accounts for these probabilities and uncertainties in data”. [752] Any instances of the true contributor not being detected are just matters that are already bound up in the lower match statistics that were reported and Dr Perlin’s description of error rates.

35. [379]

    A contention that evidence was wrongly admitted at trial can amount to, or give rise to, a “wrong decision of any question of law” within the meaning of s 6(1) of the Criminal Appeal Act 1912 (Filippou v The Queen (2015) 256 CLR 47; [2015] HCA 29 at [13]; Weiss v The Queen (2005) 224 CLR 300; [2005] HCA 81 at [17] to [18]). It otherwise constitutes a miscarriage of a justice within the third limb of s 6(1) (GBF v The Queen [2020] HCA 40 at [24] per Kiefel CJ, Bell, Keane, Gordon and Edelman JJ). However, it does not necessarily constitute a “ground which involves a question of law alone” within the meaning of s 5(1)(a) of the Criminal Appeal Act. That is so in this case because no question has been stated which can be “considered separately from the facts with which it may be connected in a given case” (Williams v The Queen (1986) 161 CLR 278 at 287 per Gibbs CJ; [1986] HCA 88; Orr v Cobar Management Pty Ltd [2020] NSWCCA 220 at [109] per Bathurst CJ and Bell P). Accordingly, a grant of leave under s 5(1)(b) of the Criminal Appeal Act is required to raise this ground. Given the absence of merit in the objections raised on appeal and that many of them involve or reflect contentions that could have been but were not raised before Johnson J, leave to raise this ground is refused.

Ground 2: Absence of a Voir Dire and Admissibility

1. [380]

   Ground 2 contends that Fullerton J erred in disallowing further evidence and submissions on a voir dire on the admissibility of the evidence of Dr Perlin, and as a result inadmissible evidence was placed before the jury.

2. [381]

   Although the bulk of the contentions raised in relation to this ground so far as they concern the admissibility of Dr Perlin’s evidence have been addressed, it is necessary to explain how a challenge to the admissibility of Dr Perlin’s evidence arose before the trial judge at the 2016 trial.

3. [382]

   During a break in the evidence given by Mr Walton on 21 October 2016 (ie, the second occasion he gave evidence), the Crown Prosecutor advised the trial judge that, in anticipation of the defence raising the possibility that Brenda Lin’s DNA was present in Stain 91, the Crown would seek to lead evidence from Dr Perlin on that topic. [753] It appears that the Crown Prosecutor foreshadowed adducing evidence of Dr Perlin’s peeling analysis which it was accepted was left open by Xie (No 4). [754] Counsel for the appellant then advised the trial judge that, not only would there be a challenge to the peeling evidence, there was also would be a challenge to Dr Perlin’s evidence generally based on s 79 of the Evidence Act. [755] Counsel asserted that Dr Perlin’s evidence and TrueAllele’s match statistics were effectively a “black box” as the computer source code that gives effect to his methodology was not in the public domain. [756] The argument resumed in the absence of the jury after Mr Walton gave further evidence. Counsel for the appellant submitted that, in the absence of either the source code or “retrospective validation in this jurisdiction … in respect of five people”, admissibility had not been demonstrated. [757]

4. [383]

   The submissions ceased and Mr Walton resumed his evidence before the jury. In cross‑examination he agreed that he was not provided with the source code for TrueAllele, but added he “would ... not be able to assess that anyway” as it would require computer expertise. [758] He was also cross‑examined on the validation of TrueAllele. As noted, Mr Walton explained that TrueAllele had been validated for four contributors [759] but said he was not aware whether it had been validated for related individuals. [760]

5. [384]

   Before proceedings resumed on the following Monday, 24 October 2016, counsel for the appellant provided written submissions which referred to an absence of “validation for four or more persons in a mixture constituted by individuals who are related by blood in the first degree”. [761] Further submissions in respect of the challenge were made during the course of that day. The Crown submitted that the supposed absence of validation did not affect the admissibility of Dr Perlin’s evidence, nor did the absence of the source code, as the statistical methodology of TrueAllele had been explained. [762]

6. [385]

   During submissions on this topic on the morning of 25 October 2016, the Crown Prosecutor again contended that there was no need for a voir dire as neither the absence of access to the source code or independent validation were relevant to admissibility. [763] The Crown Prosecutor referred to Tuite. The trial judge appeared to agree. [764] Counsel for the appellant then made further submissions about the supposed necessity to access the source code for TrueAllele, but eventually confined the challenge to a complaint about the lack of validation as follows: [765]

7. [386]

   The Crown Prosecutor then clarified that she proposed to lead evidence from Dr Perlin about the probability of the presence of DNA from Irene, Lily and Brenda Lin in Stain 91, [766] but would not press the peeling analysis. [767] Counsel for the appellant confirmed that the “foundational admissibility is still challenged pursuant to s 79” of the Evidence Act and he relied on his written submissions “in that respect”. [768] For the third time, the Crown Prosecutor submitted that the grounds of objection did not raise any issue concerning s 79, and added that, insofar as Tuite addressed reliability, it relied on the reasoning in Dupas. [769]

8. [387]

   The trial judge then stated as follows: [770]

9. [388]

   There was a debate on appeal as to whether this extract reveals a refusal by the trial judge to allow questioning of Dr Perlin on a voir dire on the topic of validation or merely the expression of a strong preliminary view to that effect such that it was open to counsel for the appellant to press this issue further. It is not necessary to resolve that debate. This ground can be addressed on the assumption favourable to the appellant that this represented a definitive refusal by her Honour to allow questioning of Dr Perlin on a voir dire concerning the point raised and a ruling rejecting the challenge to Dr Perlin’s evidence based on s 79 of the Evidence Act.

10. [389]

    Although her Honour referred to “putting my thoughts down into judgment form” it seems no judgment was provided. It is not uncommon for trials to be completed with reasons for rulings still outstanding and that is especially understandable in a case such as this where the task of summing up was such a colossal exercise. A party with an interest in seeking reasons can request they be provided after the summing up is complete, or even after a verdict is returned. No request was made. In this case it is of no moment that reasons were not provided as the basis for her Honour’s ruling is apparent from the transcript of the extensive submissions. Ultimately, the argument reduced to a challenge to the admissibility of Dr Perlin’s evidence based on s 79 of the Evidence Act because of the absence of a validation study of TrueAllele for four person mixtures of related persons. Her Honour rejected the contention on the basis of the reasoning in Tuite (and to the extent that Tuite contemplated that the absence of validation affected the reliability of the evidence it was inconsistent with IMM). Given that conclusion, there was no need to examine Dr Perlin (further) on a voir dire about TrueAllele’s validation. It follows from the above analysis that we agree with the trial judge’s conclusion and ruling.

11. [390]

    The appellant’s contentions on appeal about the admissibility of Dr Perlin’s evidence went beyond the complaint about validation that was raised at the 2016 trial, although they included that complaint. In any event, they have all been addressed. [771] It is only necessary to note two further points.

12. [391]

    First, the appellant submitted that examination of Dr Perlin and the relevant validation studies “would have shown that Dr Perlin’s specialised knowledge” is limited in the way the appellant asserted in Ground 1. The evidence adduced on the voir dire before Johnson J demonstrated to the contrary, as did the evidence in this Court. In light of the confined challenge that was (ultimately) outlined to the trial judge at the 2016 trial, the extensive evidence on the voir dire before Johnson J that her Honour reviewed, and the decision in Tuite, her Honour was correct to determine (or indicate) that further questioning of Dr Perlin about validation was not required.

13. [392]

    Second, the appellant’s submissions under this ground included the contention that “[g]iven the instances where Dr Perlin in fact did not choose the highest match statistic for a particular inferred genotype to rely on, it may be doubted that he even has a subjective belief that picking the highest amongst inclusionary match statistics points to the correct contributor”. (It was also contended that “[h]e certainly does not have specialised knowledge that it does”.) [772] As noted above, Dr Perlin explained the basis upon which he reported a particular result. He provided a summary of that to the jury at the 2016 trial. [773] He did not articulate a “belief that [simply] picking the highest amongst inclusionary match statistics points to the correct contributor”. Otherwise, this submission appears to be attacking Dr Perlin’s honesty as a witness on a basis that was not put to him at the 2016 trial or on appeal when the opportunity and the obligation to do so arose.

14. [393]

    At least some aspects of this ground reflect an argument raised before the trial judge. Accordingly, we grant leave to raise this ground of appeal but reject it.

Ground 3: Miscarriage of Justice

1. [394]

   Ground 3 of the appeal contends that a miscarriage of justice was occasioned by the evidence given by Dr Perlin which was said to be “emphasised by the manner in which such evidence was addressed upon by counsel” and the trial judge’s summing up. This ground seeks to invoke the third limb of s 6(1) of the Criminal Appeal Act. The written submissions in support of this ground identify a number of “failings” on the part of Dr Perlin which, although not cross referenced, seem to reflect various complaints which have been addressed above and rejected. For the sake of completeness, it is necessary to note them.

2. [395]

   The appellant’s submissions contended that those parts of Dr Perlin’s evidence which revealed numerous examples of the prosecutor’s fallacy gave rise to a miscarriage of justice. [774] Those contentions are addressed above.

3. [396]

   The appellant’s submissions contended that Dr Perlin’s failure to explain that the match statistic “says nothing regarding the comparative likelihood of the relevant genotype matching a related person or someone with an incidentally similar genotype” and his failure to explain the supposedly limited extent of the validation studies in relation to relatives of donors gave rise to a miscarriage of justice. [775] The premise of both complaints has not been established. In relation to the former, the evidence, especially the slides, were clear in explaining that the match statistic involves a comparison to a random person in the (Asian) population. [776] Otherwise, so much of his evidence that involved comparisons to related persons concerned Brenda Lin and shadowing and the limits of that analysis were explained. [777] The latter complaint has already been addressed, [778] as has a related submission that Dr Perlin falsely stated that “TrueAllele had been independently validated for four related individuals”. [779]

4. [397]

   The appellant’s submissions contended that Dr Perlin’s expression of an “opinion that ‘false' inclusions are rarely, if ever, seen with match statistics over 1,000” constituted a miscarriage of justice. [780] It was submitted that opinion was “used to convert a possible association of the reference samples with [Stain 91] to a positive identification”. This was said to be “particularly misleading” when the supposedly billions of other potential genotypes “produced for persons who cannot have truly been the contributor to the particular separated out genotype under consideration”. [781] As best as can be ascertained, the latter part of this submission is a reference to the alleged superior matching (theoretical) genotypes that the appellant contends TrueAllele ignored by using the distribution of the genotype of the reference sample in the population as the denominator. This contention has been addressed above. [782] It fails to address the statistical methodology that underlies TrueAllele which Dr Perlin repeatedly explained. [783] Otherwise, to the extent that the appellant refers to “false positives”, Dr Perlin’s evidence on that topic was supported by the validation studies and his evidence was that the concept of false positives include low match statistics, discordant results and results achieved by reason of “shadowing”. [784]

5. [398]

   A similar complaint concerns Dr Perlin’s evidence in response to the question of whether “there’s no possibility … that neither of them [Irene or Lily Lin] are in there”. Dr Perlin said “[n]o, based on what I’m seeing”. [785] Complaint is also made about his references to each of Min, Terry and Henry Lin’s DNA being included in the sample. [786] It was submitted that he was not qualified to give that evidence and it was disproved by the case packet data produced on the voir dire. Both of those contentions have been addressed and rejected. Otherwise, it was conceded at the 2016 trial that each of Min, Terry and Henry Lin’s DNA was present in Stain 91.

6. [399]

   The appellant’s submissions contended that Dr Perlin’s failure to explain that “the relevant separate inferred genotypes are not a discrete full genotype but a list for each separated out contributor of alternative probabilities at each locus” occasioned a miscarriage of justice. [787] Dr Perlin did explain that and it was otherwise evident from slides 9 and 10. [788]

7. [400]

   The appellant’s submissions contended that Dr Perlin’s failure to explain “to the jury the uncertainty of the data, the limitations of probability reasoning, and the particular problem of application of probability to something which has in fact already occurred (rather than predictive of future events)” occasioned a miscarriage of justice. [789] This submission does not appear to be tethered to any specific complaint. Instead, it simply decries the use of statistical evidence to determine the likelihood of the occurrence of past events. The entirety of Dr Perlin’s evidence was devoted to the topic of explaining probability reasoning and uncertainty, as well as quantifying the latter. None of the appellant’s complaints about any particular “limitation” on that evidence have been established. Otherwise, the use of statistical evidence in relation to DNA material, as well as the use of probabilistic reasoning to determine the likelihood of the occurrence of past events, is well recognised (GK; Strong v Woolworths (2012) 246 CLR 182; [2012] HCA 5 at [34]).

8. [401]

   The appellant’s submissions contended that Dr Perlin’s failure to explain “to the jury the great number of applications of the system where multiple inclusionary results were produced, for the same inferred genotype, for multiple relatives” occasioned a miscarriage of justice. [790] This was explained to the jury [791] and no further explanation was warranted as it does not have the significance that the appellant asserts. [792] Similarly, the appellant contended that failing to reveal that in some instances “one person produced the highest match statistic for multiple or even all separated out contributors on the one run, [when there could] only have truly been one such contributor” occasioned a miscarriage of justice. [793] The misconceived premise of this submission has also been addressed. [794]

9. [402]

   One part of the appellant’s submissions under this ground complains that the trial judge disallowed a question where Dr Perlin was asked to confirm he has no basis to say “it was more or less probable that Kathy [Lin] can take her place in the slot of Irene [Lin]”. The relevant part of the cross‑examination of Dr Perlin was the following exchange: [795]

10. [403]

    Counsel did not press the question or seek a ruling. Instead, he proceeded to ask Dr Perlin about the sharing of alleles between Min Lin and his sister. [796] Later in his address to the jury, counsel for the appellant referred to this evidence and submitted that “[t]he issue there is simply that Kathy [Lin] was not run ... but is a person who, … , on the basis of what Mr Walton has told you, has a number of common types or alleles because of the blood relationship with Min [Lin]”. [797]

11. [404]

    The appellant’s submissions contended that the emphasised question above was not impermissible and if it was answered that would have served to reinforce the limits of the analysis. We do not accept that the trial judge disallowed the question. Instead, her Honour only queried its utility. Counsel appeared to realise he had secured the evidence he needed then moved on. His address to the jury was based on that evidence. An affirmative answer to the emphasised question would not have enhanced the submission. The above passage does not reveal a miscarriage of justice.

12. [405]

    The appellant’s submissions contended that the failure of Dr Perlin “to reveal the information available to the witness about the possible gender of separated out contributors”, as well as specifying “the limitations of probability”, occasioned a miscarriage of justice. [798] As already explained, in addressing shadowing, Dr Perlin explained to the jury the significance of the relatively high match statistics for Brenda Lin being associated with even higher match statistics for her male relatives, ie, “shadowing male relatives” and being “carried on for the ride”, [799] whereas Lily and Irene Lin were not. [800] Otherwise, to the extent that this is a complaint about the reporting of match statistics, it has also been addressed. [801]

13. [406]

    The written submissions in support of this ground also repeated the various complaints about Dr Perlin’s evidence in relation to shadowing, [802] all of which have been addressed. [803] No miscarriage of justice has been demonstrated. Only two matters should be noted.

14. [407]

    First, one of the complaints concerns Dr Perlin’s answer about whether Brenda Lin was shadowing her female relatives. [804] The only evidence to that effect was ambiguous in that Dr Perlin was asked whether she was either shadowing her female relatives or her male relatives and answered “yes”. [805] This could have been an acceptance of both or either. In the remainder of his evidence Dr Perlin only referred to Brenda Lin shadowing her male relatives.

15. [408]

    A related complaint was made in the oral submissions on appeal as part of the suggestion that Dr Perlin “entirely and inappropriately glossed over” the match statistics of 4.71 in row 13 and 3.16 in row 19, addressed above. [806] In particular, it was contended that a miscarriage of justice was occasioned by so much of the Crown Prosecutor’s address that referred to Dr Perlin describing Brenda Lin as shadowing her male relatives for the four contributor runs because that was not the case for the four contributor runs listed in rows 13 and 19 of Annexure 1 [807] which are said to be female fractions. The relevant part of the Crown Prosecutor’s address is set out at [179]. The reference in that extract to shadowing the male relatives for four assumed contributors was not tied to a particular inferred contributor on a particular run. The address reflected a sufficiently accurate summary of the overall effect of Dr Perlin’s evidence at the 2016 trial. To the extent necessary, the summary of his evidence was confirmed by the evidence that Dr Perlin gave in this Court noted above. [808]

16. [409]

    It was also contended that a miscarriage was occasioned because the trial judge’s summing up repeated the supposed effect of Dr Perlin’s evidence that Brenda Lin was shadowing her female relatives when that was said to be “patently wrong” and evidence Dr Perlin was not qualified to give. [809] The complaint of a lack of qualification has already been addressed. As for the balance of the complaint the relevant part of the summing up is set out at [182]. Although that summary refers, as Dr Perlin did in his evidence in this Court, to the similarities in allele pairs between all the relatives, the trial judge did not expressly state that Brenda Lin was shadowing her female relatives, only her male relatives. Again, the summing up reflects a sufficiently accurate summary of the overall effect of Dr Perlin’s evidence at the 2016 trial. To the extent necessary, it was confirmed by the evidence that Dr Perlin gave in this Court noted above. [810]

17. [410]

    Second, the appellant’s submissions refer to Dr Perlin’s opinion about the absence of shadowing to explain Terry and Henry Lin’s match statistics. [811] At the risk of repetition, Dr Perlin rejected the suggestion that they were shadowing each other or their father because of the better separation that was achieved when a higher number of contributors were assumed and that did not occur with Brenda Lin’s DNA. [812]

18. [411]

    The balance of the complaints made in relation to this ground either concern Dr Perlin’s approach to reporting match statistics [813] or concern the supposed uncertainty with the positive match statistics derived for Irene and Lily Lin. [814] Again, these matters have been addressed. [815]

19. [412]

    We would grant leave to raise this ground of appeal, but reject the ground.

Ground 8 and DNA Evidence

1. [413]

   As noted, Ground 8 of the appeal contends that a miscarriage of justice was occasioned by various “acts and omissions of the applicant’s counsel at trial”.

2. [414]

   Six of the particulars to Ground 8 concern the approach taken by counsel at the 2016 trial to the evidence of Dr Perlin. Each will be addressed in turn but it is appropriate to commence with the sixth particular which concerns the concession by trial counsel for the appellant that each of Min, Terry and Henry Lin’s DNA was present in the DNA mixture obtained from Stain 91. [816]

3. [415]

   As framed this ground of appeal seeks to invoke the third limb of s 6(1) of the Criminal Appeal Act. With this ground, the relevant inquiry is whether what occurred or did not occur at the trial occasioned a miscarriage of justice (TKWJ at [79] per McHugh J; Ali v R [2005] HCA 8; (2005) 214 ALR 1 at [18] per Hayne J; “Ali”). In some cases the alleged failings of counsel are of such magnitude that they cause the trial to become unfair, such as a failure to cross‑examine a critical witness or a failure to address the jury (TKWJ at [76]; Nudd v R [2006] HCA 9; (2005) 225 ALR 161 at [19] per Gleeson CJ and [87] per Kirby J; “Nudd”). The alleged failings in this case are not of that kind. Otherwise a determination of whether the alleged failings of counsel give rise to a miscarriage of justice requires a consideration of what ultimately did or did not occur at the trial, whether there was some material irregularity in the trial and whether there is a significant possibility that the acts or omissions of which complaint is made affected the outcome of the trial (Nudd at [24] per Gummow and Hayne JJ; TKWJ at [31]‑[33] per Gaudron J, at [79] and [97] per McHugh J, at [101] per Gummow J and at [103]-[108] per Hayne J). In assessing the conduct of counsel, the relevant standard is whether or not the conduct was “incapable of rational explanation on forensic grounds” (Nudd at [16]; Hanna v R [2017] NSWCCA 168 at [17]).

4. [416]

   In Matthews v R [2013] NSWCCA 187 (“Matthews”), this Court observed as follows about that inquiry (at [63]):

5. [417]

   It is necessary to say something further about the third and fourth propositions and the general issue of the receipt of evidence in support of this ground of appeal. The third and fourth propositions in part reflect the practical problems that confront appellate courts in assessing the performance of trial counsel (Nudd at [10] per Gleeson CJ). Nudd and TKJW nevertheless recognised that in some limited class of cases it may be necessary for the appeal court to receive evidence of why counsel acted in the way they did. In Nudd, Gleeson CJ gave as an example that “it may be material to know that counsel took a certain course upon the instructions of the client” (at [10]).

6. [418]

   This approach of limiting the receipt of evidence as to why counsel acted is to be distinguished, or is at least distinguishable, from the appeal court receiving evidence about the circumstances that counsel faced as part of an objective assessment of their conduct of the appellant’s case.

7. [419]

   In Nudd, the complaints against trial counsel included that he “failed to take appropriate instructions from the appellant” and “failed to appropriately advise the appellant in relation to giving evidence” (at [149]). The Queensland Court of Appeal received evidence from the appellant as to his version of events surrounding the offence (at [150]). Similarly, in Matthews this Court received evidence from the appellant as to the instructions he allegedly gave to his trial counsel (at [65]). That part of the appeal in Matthews was determined on the assumption that that evidence was accepted and the conduct of counsel was assessed objectively without receiving evidence as to why counsel took a particular course of action (at [69] to [74]).

8. [420]

   In Vella v R; Siskos v R [2015] NSWCCA 148, this Court referred to the difficulty in addressing a complaint of this kind without, inter alia, evidence “of at least the material available to trial Counsel” (at [91]). In that case, an affidavit from trial counsel was read in response to a complaint that good character evidence should have been, but was not, adduced by trial counsel. So much of that affidavit that recounted “various items of evidence that were potentially available to the Crown to raise in response to any case on good character” and the instructions received from the appellant including his response to the Crown’s material, was admitted and considered (at [96] to [97]). However, that part of trial counsel’s evidence that involved his recollection of his assessment of the likely strength of the evidence available to the Crown to rebut evidence of good character was not considered (at [98]).

9. [421]

   In this case, no evidence was filed from counsel who appeared at the 2016 trial explaining why he made the concession noted above. Given the principles outlined above and the nature of the complaints made that was not necessary and arguably such evidence would have been inadmissible. However, no evidence was filed concerning the evidence and material available to counsel which may have informed his decision and more importantly enabled an objective assessment of it to be undertaken. This is of significance to particular (vi).

10. [422]

    At various times during the voir dire and the 2016 trial, reference was made to the fact that the appellant’s legal team had available to them some form of expert in DNA. This was conceded on appeal. [817] It would appear to be highly relevant to an objective assessment of the conduct of counsel in making the concession the subject of particular (vi) to ascertain what expert advice was provided to him or her about Dr Perlin’s evidence or TrueAllele. On the appeal, Senior Counsel for the appellant submitted that this material was not relevant because the assessment of counsel’s conduct was to be undertaken “objectively”. [818] This appears to be a reference to assessing counsel’s conduct having regard to the attempt to relitigate the charges against the appellant afresh in this Court. This is not the form of objective assessment of the conduct of counsel envisaged by Nudd and TKJW. Instead, what is to be undertaken is an assessment of the conduct of counsel in the context of the trial that actually unfolded. To conclude otherwise would undermine the “accusatory and adversarial process” that is a criminal trial and to which this ground of appeal is a limited exception (TKJW at [106] per Hayne J).

11. [423]

    One approach to this issue is to start with the proposition that the onus of proof of any relevant fact in relation to this ground of appeal rests upon the appellant. If an appellant fails to adduce evidence that is highly relevant to this ground then, leaving aside any particular inferences that might be drawn from that failure, it may be that the absence of that evidence will make the ground that much more difficult to establish (Blatch v Archer (1774) 1 Cowp 63 at 65; 98 ER 969 at 970; Australian Securities and Investments Commission v Hellicar (2012) 247 CLR 345; [2012] HCA 17 at [165] to [168]). To develop that approach would appear to require a conclusion that the raising of this ground of appeal involves a loss of client legal privilege over the subject matter of the ground under s 122(2) of the Evidence Act. In the end result, it is not necessary to decide these issues as particular (vi) fails without the necessity to consider anything that flows from the absence of evidence about what expert assistance was available to any of the counsel who appeared for the appellant at his four trials, including the 2016 trial.

12. [424]

    In his address to the jury at the 2015 trial, Senior Counsel then appearing for the appellant referred to the evidence of Mr Walton and Dr Perlin and submitted that it “would allow for a comfortable conclusion that it is likely that the DNA on the floor was shed by Terry and Henry”. [819] He pointed out that “Brenda, Terry, Henry spent time sweating in the garage” and that the appellant and Kathy Lin could not be excluded as minor contributors. [820] He submitted: [821]

13. [425]

    Further, at the 2015 trial, but in the absence of the jury, Senior Counsel appearing for the appellant accepted that the effect of the Yfiler evidence was that Min Lin’s DNA may also have been present in Stain 91. [822] Mr Walton’s evidence at the 2016 trial strongly supports that conclusion. His evidence pointed strongly to at least three males being present in the major component all with the Y profile of Henry, Terry and Min Lin. [823] Further, counsel at the 2016 trial had the benefit of Dr Perlin’s evidence from the voir dire and the 2015 trial, as well as Annexure 1, which contained consistently high match statistics for each of Min, Terry and Henry Lin.

14. [426]

    It was in these circumstances that trial counsel made his concession at the 2016 trial. It meant that he did not have to challenge Dr Perlin on an issue on which his evidence was particularly strong and which was also strongly supported by Mr Walton, namely the presence of Min, Terry and Henry Lin’s DNA in Stain 91. Instead, it meant that counsel was able to focus on the possibility of Brenda Lin’s DNA also being present, a contention that had at least some support in the match statistics in Annexure 1. The point is that there was little prospect of anything being gained by trying to eliminate one of the male deceased’s DNA from Stain 91. The major goal was to have the prospect of a non‑deceased’s DNA being present in Stain 91 as that would render the evidence irrelevant in supporting the Crown’s circumstantial case. Given these matters, it follows that counsel’s concession was certainly not “incapable of rational explanation on forensic grounds” (Nudd at [16]). This particular is not made out.

15. [427]

    The first particular of this ground is that a miscarriage of justice was occasioned by trial counsel’s failure “to object to Dr Perlin's evidence engaging in the Prosecutor's Fallacy”. As it is not accepted that Dr Perlin engaged in that fallacy, this complaint falls away.

16. [428]

    The second particular of this ground is that a miscarriage of justice was occasioned by trial counsel’s failure “to object to Dr Perlin's evidence which went beyond the ruling of Johnson J and the expansion of that in the 2015 trial”. Given the above findings about the scope of the ruling by Johnson J, this complaint also falls away.

17. [429]

    The third particular of this ground is that a miscarriage of justice was occasioned by trial counsel’s “[f]ailure to cross‑examine Dr Perlin to expose the limitations of his opinions”, being the limitations explained in the appellant’s written submissions. The suggested limitations have all been addressed.

18. [430]

    The fourth particular of this ground is that trial counsel failed “to understand the relevant validation studies Dr Perlin was cross‑examined about, so as to take issue with Dr Perlin's incorrect evidence about independent validation for four and five related contributor mixtures”. A contention that trial counsel failed to “understand” something goes nowhere. In any event, the essence of the particular is a failure to cross‑examine Dr Perlin about his evidence on validation. The fifth particular of this ground concerned the consent given to the tender of “Exhibit GD” which listed the various validation studies under headings. [824] Given the above analysis of this topic these complaints are also untenable. [825] The only demonstrated misdescription in Exhibit GD was the description of the Australia Validation Report as relating to more than three contributors (although Mr Walton’s evidence was that it had been validated in NSW for four contributors by the time of the 2016 trial). [826] Counsel’s failure to detect and correct the misdescription of that study in Exhibit GD did not occasion a miscarriage of justice.

19. [431]

    The balance of this ground is addressed below after a consideration of Grounds 4 to 7.

Rulings on Evidence Adduced on Appeal

1. [432]

   There remains to be addressed the admissibility of the further evidence from Dr Perlin, Professor Gill and the appellant’s solicitor that was admitted provisionally on appeal.

2. [433]

   The Crown contended that none of that evidence answered the description of “fresh” or “new” evidence and it was all therefore inadmissible. In MRW v R [2011] NSWCCA 260 at [46] (“MRW”), Bathurst CJ identified the three questions that need to be considered where a conviction is sought to be quashed and a new trial ordered on the basis of fresh evidence, namely:

3. [434]

   With the first question, where the material in question is evidence that was in existence as at the time of the trial, the relevant issue is whether that material “could not then have been available to the appellant by the exercise on his part of reasonable diligence in the preparation of his case” (Ratten at 516 per Barwick CJ). If the material does not meet the first of the above tests, that is, if it is not fresh evidence but only new evidence, then there would only be a miscarriage of justice if the appellant satisfies this Court that the new evidence is such that, taken with the evidence at the trial, the conclusion should be drawn that he was innocent or that his guilt was not established beyond reasonable doubt (Ratten at 518 and 520).

4. [435]

   The appellant addressed the admissibility of the further evidence adduced on appeal in a submission dated 8 October 2019. The submission referred to ss 12(1)(b) and (c) of the Criminal Appeal Act which enables this Court “if it thinks it necessary or expedient in the interests of justice” to order any witness who was a compellable witness at the trial to be examined or receive the evidence, if tendered, of any witness who is not so compellable.

5. [436]

   In those submissions, the appellant sought to identify two classes of cases in which further evidence was received with the first being the receipt of “fresh” or “new” evidence. The second class was said to be typified by the decision of this Court in Cesan v DPP (Cth) [2007] NSWCCA 273; (2007) A Crim R 385 (“Cesan”) where evidence was sought to be tendered as to the conduct of a trial judge in falling asleep during part of a trial and the medical condition that caused that to occur (at [21] to [22]). Evidence of the former was objected to by the respondent on the basis that it was neither fresh nor new evidence. Basten JA dissented on the outcome in this Court but that outcome was reversed in the High Court (Cesan v The Queen (2008) 236 CLR 358; [2008] HCA 52). For present purposes, it suffices to note the following analysis by his Honour of the basis for the receipt of that evidence by this Court which appears to have been accepted by the other members of the Court (at [178] per Grove J and at [216] per Howie J):

6. [437]

   This extract confirms that the power conferred by s 12(1) of the Criminal Appeal Act to, inter alia, receive further evidence “if it thinks it necessary or expedient in the interests of justice” to do so is not a free standing power to receive evidence, but one which must be exercised having regard to the particular ground of appeal (which in turn will reflect one of the three limbs of s 6(1)). The “interests of justice” in this context are a reference to properly determining the relevant ground of appeal according to law.

7. [438]

   Thus, if what is sought to be done is, to use Basten JA’s phrase, “contradict … the jury’s verdict”, that is contend that there was other evidence not adduced at the trial that undermined the Crown case or pointed to the innocence of the accused, then the rules concerning fresh and new evidence are engaged. In this case, to the extent that any of the additional evidence was sought to be deployed on appeal in support of Grounds 1 to 3 then it was only being done for the purpose of attempting to relitigate so much of the 2016 trial that concerned the admission and treatment of DNA evidence concerning Stain 91. Hence to the extent that evidence is sought be adduced on appeal in support of those grounds, then its admission is governed by the rules pertaining to fresh or new evidence.

8. [439]

   However, the above discussion in relation to Ground 8 suggests that there is scope for the reception of evidence on appeal that is not necessarily fresh or new but which may establish what the position of counsel was when they committed the relevant act or omission said to have caused a miscarriage of justice or which may tend to establish what the effect of that act or omission was on the trial process. It is not necessary to explore the limits of those possibilities on this appeal.

9. [440]

   As noted, Dr Perlin’s report dated 19 May 2020, and his oral evidence, was received provisionally. [827] Even though the Crown retained Dr Perlin to provide his report, it contended that his report and his oral evidence was inadmissible. It follows from the above that, to the extent that this evidence concerns Grounds 1 to 3, then it is only admissible if it meets the test for fresh or new evidence. The evidence was not fresh in the sense that Dr Perlin only either reiterated or expanded upon the evidence he gave at first instance. Otherwise, none of his evidence on appeal came close to demonstrating a “significant possibility that the jury acting reasonably would have acquitted the appellant" (MRW at [46]), much less that the appellant was innocent or that his guilt was not established beyond reasonable doubt (Ratten at 520). To the contrary, the evidence only served to reinforce the effect of the evidence adduced at the 2016 trial. Dr Perlin’s evidence on appeal is not admissible in support of Grounds 1 to 3.

10. [441]

    However, so far as Ground 8 is concerned, Dr Perlin’s evidence is admissible in that it addresses what would have ensued had trial counsel for the appellant taken the various steps identified in the particulars to that ground. The fact that it would only have served to reinforce the evidence adduced at the 2016 trial does not mean that it is not admissible on this basis. Accordingly, the evidence will be admitted but subject to a limitation under s 136 of the Evidence Act restricting its use to Ground 8 of the appeal.

11. [442]

    As noted, the report of Professor Gill dated 25 October 2019 was also admitted provisionally with its status to be determined in this judgment. In particular its tender was received by the Court subject to it being “determin[ed] whether the evidence is admissible in accordance with the principles concerning the admission of new and fresh evidence on appeal” and the Court being satisfied Professor Gill has the requisite specialised knowledge to express certain opinions set out in the report. [828] It follows from the above that Professor Gill’s report is not “fresh”. Further, considered by itself or with other evidence it neither establishes a significant possibility that a jury acting reasonably would have acquitted the appellant, much less that the appellant was innocent or that his guilt was not established beyond reasonable doubt. Further, none of the particulars to Ground 8 contend that trial counsel should have obtained evidence from Professor Gill or evidence from another source to the same effect. Accordingly, the tender of Professor Gill’s report is rejected.

12. [443]

    As noted, at the hearing of the appeal an affidavit was read from the applicant’s solicitor which, inter alia, annexed the Master’s Thesis and the Greenspoon article concerning validation, they being articles referred to in Exhibit GD. Again, this evidence was admitted provisionally. [829] Given that both articles pre‑date the 2016 trial, neither of them amounts to “fresh” evidence. Further, neither of them considered individually or with other evidence demonstrate a significant possibility that a jury acting reasonably would have acquitted the appellant, much less that the appellant was innocent or that his guilt was not established beyond reasonable doubt. It follows that they are not admissible in support of Grounds 1 to 3. However, they have some relevance to particulars (iv) and (v) to Ground 8 in that they represent material that might have been the basis for counsel to contest the accuracy of Exhibit GD and cross‑examine Dr Perlin. They will be admitted for that limited purpose.

Accusations Against Dr Perlin

1. [444]

   Finally, in relation to these grounds it is necessary to record the fate of certain accusations that were made against Dr Perlin. Various interlocutory applications were made on behalf of the appellant during 2019 which resulted in the procuring and provisional receipt of additional evidence on the appeal, including evidence from Dr Perlin. The submissions made in support of those applications levelled very serious allegations against him. For example, it was submitted that at first instance he had presented his evidence in a manner that was “designed to deflect understanding of the limitations of the [TrueAllele] system in this case” and that the points raised by the appellant were “issues of significance which … [were] ... covered up by Dr Perlin to hinder exposition”. [830] During the appeal, Senior Counsel for the appellant confirmed that these allegations were maintained. [831] However, despite Dr Perlin giving oral evidence over two days in this Court, these allegations were not put to him save for the (untenable) suggestion that he deliberately refrained from advising the jury at the 2016 trial of two of Brenda Lin’s match statistics listed in Annexure 1. [832] On the last day of submissions, and after the Court observed that these matters were not put to Dr Perlin in cross‑examination, it was confirmed that the allegations of impropriety were not pressed. [833] It suffices to record that no allegation of impropriety was ultimately pursued against Dr Perlin and no basis for such an allegation was apparent on the material before this Court.

PART 7: Ground 4 – the “CSI Effect”

1. [445]

   Ground 4 of the appeal contends that her Honour misdirected the jury in providing a warning regarding the “CSI Effect”.

2. [446]

   This ground is concerned with directions the trial judge gave the jury about their assessment of evidence pertaining to the crime scene at the Boundary Road home. It was a crime scene of considerable complexity and that was for a variety of reasons including the number of deceased, the way their deaths were caused and the nature of the weapon the Crown theorised had been used. There was evidence from specialists in the examination of crime scenes and experts on aspects deduced or derived therefrom.

3. [447]

   The directions that are impugned under this ground were described, polemically, in the appellant's written submissions as "a protective CSI warning in favour of the Crown". [834]

4. [448]

   The directions followed the trial judge first giving a direction about expert witness testimony in unimpeachable terms. [835] That was followed by broad observations about some of the expert evidence in the case. [836] Next, the trial judge summarised the Crown and defence cases relating to the crime scene. [837] Her Honour then allowed the jury a short mid-afternoon break before continuing with the impugned directions. [838] Just before taking that break, her Honour said to the jury:

5. [449]

   Following the short break, her Honour gave the following directions:

6. [450]

   Her Honour proceeded to provide the jury with a broad summary of evidence pertaining to various aspects of the crime scene examination before adjourning for the day. [839] The following morning there was an application by the appellant’s counsel for a discharge of the jury on account of the “CSI direction” but it was refused. [840]

7. [451]

   The appellant contended that this was a misdirection for the following reasons: [841]

8. [452]

   It was submitted that the direction (or warning) “was not required as an aspect of her Honour’s obligation to ensure the fairness of the appellant’s trial or that the jury understood the law, the parties' cases, the real issues or the evidence”. It was submitted that the direction "intruded into the jury's role in determining facts, and was particularly problematic in such a forensically heavy case, and as it was not a point advanced by the Crown (to which the defence could have responded)”. [842]

9. [453]

   It was accepted at the hearing that the focus of the direction was upon the examination of the crime scene at the Boundary Road home. Mr Walton and Dr Perlin were mentioned in the course of the direction, but the focus was upon the origin of what they analysed rather than the analyses they carried out themselves, particularly in relation to Stain 91. Nevertheless, it was submitted that this did not diminish the complaint that the direction had the effect of diverting the jury from a critical assessment of matters based upon the Boundary Road crime scene that were "hotly contested" by the appellant "such as the order of the killings, whether there was only one person and the like". [843]

10. [454]

    Submissions were also made about the basis, or lack of basis, for the direction. The appellant's initial written submissions referred to articles it was contended would show that research did not support, but in fact detracted from, the need for a direction in the terms given by the trial judge. [844] In further written submissions filed just before the hearing, it was contended that this ground could and should be upheld without resorting to the articles. [845] Ultimately, at the hearing, the appellant accepted that the articles were irrelevant. As there distilled, the submission was that the ground would be upheld if the Court accepted that the direction had the effect of diverting the jury from any doubt it may have had about any aspect of the forensic evidence components of the Crown's circumstantial case, or the combined effect of the circumstantial case. [846]

11. [455]

    The Crown contended that the direction was limited and introductory to the jury’s analysis of the crime scene evidence. It had no application to anything beyond the scene of the murders at the Boundary Road home. [847]

12. [456]

    It was submitted that the effect of the direction was merely to warn the jury not to speculate about the evidence; in particular about what DS Harkins and Dr Raymond might have been able to give evidence about if the crime scene had been documented differently. [848] It reinforced a conventional direction at the outset of the summing up that “neither speculation, innuendo [nor] guesswork must be permitted to influence your consideration of the evidence”. [849]

13. [457]

    The Crown also argued that the direction must be seen in the context of the jury having sat through 100 days of trial – they were well aware, by that point, of the differences between crime scenes in fiction and reality. This was said to pick up on a suggestion by the defence at trial that the police officer in charge of the investigation was “writing a narrative in search of an author”. [850] The trial judge was simply reiterating that the jury should not speculate about the evidence by distinguishing works of fiction in which there is always an answer.

14. [458]

    The "CSI effect" is a concept that has been discussed in the context of a concern about greater weight being attached to forensic evidence than is warranted. The concept has also been referred to as the "white coat effect". See, for example, Morgan v R [2011] NSWCCA 257; (2011) 215 A Crim R 33 at [145] (Hidden J) and R v MK [2012] NSWCCA 110; (2012) 223 A Crim R 672 at [37] (Beech-Jones J). That is not what this ground is concerned with. The appellant's case is the opposite; a concern about the jury being encouraged to dismiss any doubt it might have arising from some perceived deficiency in the forensic evidence.

15. [459]

    The basis of her Honour’s references to a "CSI effect" is not apparent. Nor is it apparent what her Honour was referring to when saying the concept was familiar "for judges working in this division" and that she had determined to give the direction, having been "informed by academically-based research of exiting jurors". Nevertheless, the gravamen of the ground is not whether there was an authoritative foundation for the direction; it is whether the direction may have caused the trial to miscarry because it had the potential to divert the jury from a proper assessment of a significant body of evidence in the Crown case. There is no doubting the significance of the evidence; it related to matters of importance as referred to by the judge: "the number of killers, the sequence in which they were killed and the weapons or the primary weapons used to kill the deceased". [851]

16. [460]

    It is essential in considering a ground such as the present to consider the summing up of the trial judge as a whole as opposed to focussing upon sentences or parts of sentences in isolation from their context: Selby v R [2017] NSWCCA 40 at [41]; A2 v R; Magennis v R; Vaziri v R [2018] NSWCCA 174 at [1038].

17. [461]

    At a very early point of the summing up, the trial judge gave some general directions about the need for the jury to have regard to the evidence. The directions included the following:

18. [462]

    These directions were of general application; the impugned direction was specifically based upon the examination of the crime scene at the Boundary Road home. The instruction of general application was carried through to that specific subject with the addition of some other matters. In its essence, the direction conveyed the following:

19. [463]

    A major thrust of this ground was encapsulated in the final paragraph of the appellant's initial written submissions, that the trial judge had given a "protective CSI warning in favour of the Crown". [856] It was submitted at the hearing that the directions were "very firmly in favour of not penalising the Crown in connection with this body of evidence" with "nothing to balance that in any way in respect of the interests of the accused". [857] These contentions do not withstand scrutiny, particularly when regard is had to the trial judge having said that if the jury considered that the crime scene evidence supported the opinions expressed by the expects, then that is the view they should take, but: [858]

20. [464]

    There may be room for debate as to whether the direction was necessary. We certainly should not be taken as stating that it is desirable that a direction of this nature be given in all cases involving complex scientific evidence. However, for the reasons we have given, whether the direction was necessary or otherwise it did not result in a miscarriage of justice.

21. [465]

    We would grant leave under s 5(1) of the Criminal Appeal Act to raise this ground of appeal, but reject it.

PART 8: Ground 5 – Consciousness of Guilt

1. [466]

   Ground 5 of the appeal contends that a miscarriage of justice resulted from the direction given to the jury in relation to the appellant's alleged consciousness of guilt. In particular it was contended that:

2. [467]

   The appellant referred to the Crown relying upon three bodies of evidence as giving rise to an inference of consciousness of guilt: [859]

   1. (1)

      The appellant's conduct in various respects on 18 July 2009.

   2. (2)

      The appellant's destruction of shoeboxes in May 2010.

   3. (3)

      The appellant's discussions with Witness A about a "Plan B".

3. [468]

   The way the appellant’s case was crystallised in relation to this ground made it apparent that there are two different complaints concerning different evidentiary subjects. Ground 5(a) is an assertion that the trial judge failed to direct in accordance with authority about the use the jury could make of (2) and (3) above. Ground 5(b) is an assertion that the summing up was unbalanced in respect of certain aspects of (1) above.

4. [469]

   The appellant acknowledged that Rule 4 of the Criminal Appeal Rules applied to both sub-grounds because no issue was raised at the trial. It was submitted that the Court should allow this ground because there had been a miscarriage of justice. [860]

5. [470]

   Ground 5(a) involves the asserted failure of the trial judge "to give an adequate warning about the possible conduct of innocent people". Her Honour failed to give a direction that [861]

6. [471]

   It was submitted that the evidence on these subjects invoked reasoning like the lies considered by the High Court of Australia in Edwards v The Queen (1993) 178 CLR 193; [1993] HCA 63. Accordingly, the protective aspect of the Edwards direction was required to avoid a miscarriage of justice and was not given. [862]

7. [472]

   The appellant referred to the written directions provided by the trial judge: [863]

8. [473]

   It was necessary for the written direction to be in broad enough terms to cover two types of conduct that the Crown relied upon for this mode of reasoning: conduct which the appellant admitted but for which he advanced an alternative explanation and conduct which he disputed. For example, he admitted to the destruction of shoeboxes but had an innocent explanation for it, while he denied the Crown's inculpatory characterisation of the Plan B issue.

9. [474]

   As mentioned in the earlier review of the Crown case, a circumstance relied upon by the Crown was that the appellant owned a pair of ASICS Gel Evation II sports shoes. [864] It was one of only three ASICS sports shoe models capable of leaving 20 sole impressions in blood found in the crime scene in the upper storey of the Boundary Road home. [865] His shoe size was 9.5 and the impressions were thought to be in the range of shoe sizes 8.5 to 10.5. [866]

10. [475]

    The following summary of the Crown case in relation to the shoebox destruction is derived from the Crown's closing address. [867]

11. [476]

    Kathy Lin, the appellant’s wife, was spoken to at the NSW Crime Commission on 6 May 2010 in the presence of her solicitor. They were told that the investigation had revealed there was a single male killer who was wearing an ASICS sports shoe of a consistent size. The Crown case was that this information was passed on to the appellant by either his wife or the solicitor. That night, a surveillance device in his home captured him destroying shoeboxes. He cut them into small pieces and put them into a bucket of water, which he then poured into the toilet.

12. [477]

    Kathy Lin had given evidence that the family kept shoeboxes for storing other shoes. She put a blue sticker on the box on which was written the relevant family member's name and the type of shoe. It was the Crown case that multiple shoeboxes were destroyed on this night by the appellant, potentially three because three blue stickers were recovered by police when they carried out a search. They each bore the appellant's name.

13. [478]

    The Crown argued that, because Kathy Lin was present, the appellant would not have merely destroyed the box that related to his pair of ASICS Gel Evation II shoes. He could not explain in innocent terms why he destroyed the box for a specific pair of shoes; that which he wore during the murders. Consequently, he destroyed multiple ASICS shoeboxes and maintained a façade to his wife that he was doing so out of fear of being set up by the police.

14. [479]

    The Crown submitted that the appellant destroyed an ASICS Gel Evation II shoebox because it was the last link to his possession of the shoes that he had worn during the murders. He previously got rid of the shoes but, with the information he received on 6 May 2010, he needed to get rid of the shoebox. The Crown Prosecutor anticipated a defence submission that the appellant was under considerable pressure because he was concerned that he was a suspect and was going to be framed for the murders. She submitted that fear of being framed was part of a story he was conveying to his wife. It was the Crown case that the appellant was under pressure, but that was because of his knowledge that he was responsible for the murders.

15. [480]

    Another component of the circumstantial case, also supporting an inference of consciousness of guilt, was the appellant's engagement in prison while on remand with a person referred to as "Witness A". The Crown case, which we have previously noted briefly, [868] was summarised in more detail by the appellant's counsel at the hearing: [869]

16. [481]

    The Crown contended in this Court that it had pitched its case more highly than the appellant's submissions suggested (e.g. "there was active pursuit of Plan B" [871] ) but nothing relevant to the determination of the ground appears to turn on the distinction.

17. [482]

    The appellant submitted in relation to the shoebox and Plan B that it was necessary for the trial judge to direct the jury that innocent people may conduct themselves in such ways for reasons not arising from a consciousness of guilt. There were two parts to the directions said to be necessary by the High Court in Edwards v The Queen, and the trial judge only gave the directions in accordance with the first part. [872]

18. [483]

    The appellant had advanced a reason for his destruction of the shoeboxes, namely avoidance of an unjust accusation. However, it was submitted that the trial judge was required not only to remind the jury of it being an alternative explanation for that which the Crown contended; her Honour was also obliged to direct the jury that, hypothetically, there could be other explanations.

19. [484]

    In relation to the Plan B issue, like in Edwards v The Queen, [873] there was no alternative explanation advanced by the appellant at trial but there remained the obligation to direct the jury about hypothetical explanations for conduct of that type.

20. [485]

    It was also submitted that the second part of the Edwards direction amounted to a warning to avoid a specific type of risk that was like the requirement for there being a warning in relation to certain other types of evidence such as identification. It was submitted (uncontroversially) that in relation to identification evidence, it was not sufficient to direct a jury that it should not be acted upon unless the jury was satisfied it was correct and then simply to remind the jury of the defence submissions as to why it may be unreliable or mistaken. [874]

21. [486]

    In contrast to the shoebox issue, there was no explanation advanced for the appellant's conduct in relation to the Plan B issue. However, the submission was the same; that the trial judge was required to give a direction as to why an innocent man in the appellant's position might have been prepared to engage with Witness A in the way the Crown contended. [875]

22. [487]

    The Crown referred to the fact that the appellant had denied that he ever seriously contemplated the plan. Detailed submissions were made by defence counsel in closing address as to why the jury would reject the Crown contention that the appellant was willing to contemplate Plan B. The Crown submitted that in these circumstances it would have undermined the defence case if the judge had suggested reasons why the appellant may have engaged in the conduct alleged. The fact that counsel sought no redirection was said to be consistent with an appreciation of that risk. [876]

23. [488]

    In response to that submission, the appellant argued that there was an analogy with Edwards v The Queen itself in that there was a dispute about the conduct (alleged lying in evidence in court) but the High Court held nonetheless that the jury should have been directed as to how it should take the asserted conduct into account if satisfied that it had been established. It was submitted that the jury in such a case should be directed to determine whether the Crown had proved that the conduct occurred and "additionally, that there may be many reasons why an innocent person may engage with someone in circumstances such as this or contemplate a possibility of irregular dealing with charges such as to avoid an unjust conviction". [877]

24. [489]

    The appellant was invited to draft the direction that he contended should have been given to meet the complaint being raised now (but not at trial). A document was filed with leave after the conclusion of the hearing that set out the following directions as to each of the two issues. [878]

25. [490]

    At the hearing, it was accepted that fear of an unjust accusation as a hypothetical in relation to the shoebox issue was precisely the same as the possibility actually contended for by the appellant and that there was no other realistic possibility. However, the submission was that the trial judge should have told the jury, as an objective fact, that people may destroy evidentiary material because of a fear of wrongful implication in a crime. [879]

26. [491]

    The appellant relied upon the following passage in the joint majority judgment of Deane, Dawson and Gaudron JJ in Edwards v The Queen (at 210-211):

27. [492]

    The second paragraph of that extract is the basis of the "protective" direction as it was described in the appellant's submissions; the component said to be absent from the trial judge's summing up. The essential aspect of this paragraph (which we have emphasised) is the first sentence. The whole paragraph may be broken down to the following components:

28. [493]

    Broadhurst v The Queen [1964] AC 441 is cited in a footnote to the first sentence of the second paragraph as an authority supporting the proposition therein. In that case, Devlin LJ said (at 457):

29. [494]

    The extract from Edwards v The Queen echoes what was said by Gleeson CJ in R v Heyde (1990) 20 NSWLR 234 (at 236-7):

30. [495]

    Once again, the essential element of what it is said should be conveyed to a jury is that there may be explanations for the conduct aside from a consciousness of guilt.

31. [496]

    While Edwards v The Queen was concerned with post-offence lies (in fact, lies in giving evidence in the course of Edwards' trial), the principles are applicable, with appropriate adaptation, to other forms of post-offence conduct from which an inference of consciousness of guilt may arise. For example, in R v Cook [2004] NSWCCA 52 the issue was flight, about which Simpson J (as her Honour then was) said (at [25]; [50]):

32. [497]

    The emphasised sentence in that extract is clearly an allusion to the essential part of the second paragraph of the extract from Edwards v The Queen discussed above.

33. [498]

    Simpson J endorsed the need for hypothetical explanations to be given for seemingly incriminating post-offence conduct in R v Cook (at [52]):

34. [499]

    There is uncertainty as to whether her Honour meant to convey that a direction in hypothetical terms should be given in all cases regardless of whether there is an alternative explanation. This arises because of ambiguity in the second and third sentences. The use of "even where" in the second sentence may suggest the direction should be given in hypothetical terms regardless of whether there is evidence of an alternative explanation. If that is what her Honour meant, the use of "even where" would be more logical if the balance of the sentence was in the positive rather than the negative (ie, even where there is evidence of an alternative explanation). On the other hand, the third sentence would fit more logically if the word "even" did not appear in the second sentence (ie, the direction should be given in hypothetical terms where there is no evidence of an alternative explanation and it should be given by reference to any alternative explanation where there is one). We consider it most likely that her Honour intended to convey the first of those possible interpretations.

35. [500]

    The appellant also referred to a five-judge bench decision of the Victorian Court of Appeal in R v Ciantar (2006) 16 VR 26; [2006] VSCA 263. The case involved an offence of culpable driving causing death arising from a “hit and run” collision in which it was alleged the offender had a high blood alcohol reading at the relevant time. He claimed that the blood alcohol reading was a result of alcohol he consumed after the event. The Crown Prosecutor submitted in closing address that consciousness of guilt could be inferred from either the accused having consumed alcohol after the collision, or his lying about having done so. It was held to be a miscarriage of justice that the trial judge did not give an Edwards direction. Speaking generally, their Honours said the directions that should be given to a jury in relation to consciousness of guilt included (at [86]):

36. [501]

    Later in the judgment, when describing how the jury should have been directed in the instant case, it was said that if the jury concluded that the appellant had lied about drinking after the accident, an Edwards direction should have been given including:

37. [502]

    If the jury concluded that the appellant drank alcohol after the accident in order to mask the fact that he had been drinking before the accident, an Edwards direction should have been given including:

38. [503]

    In the present case the Court was not taken to any direct authority for a proposition that a trial judge must suggest hypothetical explanations that are delivered with a "judicial imprimatur", [881] as was suggested in the appellant's submissions. [882] The assertion that there was such a requirement was derived only by inference from the cases referred to above. However, a case in which such a point was raised is R v Finnan [2005] VSCA 151. It involved an appeal against conviction for offences arising from a violent affray outside a hotel that led to the trial of several accused including Mr Finnan. The Crown relied upon lies he told to police, one being that he had not been at the hotel on the night in question and another that he denied knowing that people left his house with weapons. He did not give evidence, but his counsel submitted to the jury that a possible reason for the first lie was that he was underage and should not have been at the hotel in the first place. It was submitted that he denied knowing about people going in and out of his house because if he had not, then he would be in a position where the police would be asking him who those people were and he may not have wished to implicate them.

39. [504]

    It was considered by Osborn AJA that the jury had been correctly directed that they needed to be satisfied that the statements were made, they were deliberate lies, and they were told in order to conceal the truth to avoid implication in crimes the accused was aware he had committed. Notably, the direction also included that the jury "must consider other possibilities such as a desire to avoid implication in crimes in which he was not involved or to avoid telling police that he had been present because of the potential consequences of that simple admission" (at [14]). Defence counsel, however, sought and obtained a redirection in which the trial judge repeated in more detail the arguments that had been put by counsel.

40. [505]

    The complaint on appeal was that the trial judge had simply repeated the arguments of counsel and that this repetition was not given as a direction of law with the authority of the judge's office behind it. Osborn AJA (with whom Vincent and Nettle JJA agreed) responded (at [18] to [19]):

41. [506]

    It is necessary to make an observation about the cases which suggest a need for hypothetical explanations to be given. As indicated earlier, the purpose of providing them is to illustrate and emphasise the essential aspect of the direction to be given to a jury: people may conduct themselves in a way that might suggest a consciousness of guilt but in reality such conduct may be prompted by something else. The purpose is to avoid the jury jumping to the erroneous conclusion referred to by Gleeson CJ in Heyde v R as "one which people not infrequently make".

42. [507]

    "Panic" is often cited as a hypothetical example but where there is no urgency attending the conduct it may be inapt, as it may be where the conduct is not momentary but engaged in over an extended period. Even where panic might be apt, it is devoid of meaning unless the reason for the panic is provided. People usually do not panic without reason. In this context, what might often be the cause is fear of being unjustly accused. Consuming alcohol after a motor vehicle collision because of a condition of alcohol dependence in a crisis was suggested in R v Ciantar. If this did not have a foundation in the evidence, providing that as a hypothetical explanation would be to invite the jury to engage in baseless speculation about whether such a condition afflicted the accused.

43. [508]

    The suggestion in R v Cook of directing a jury that the conduct does not point to "some other offence or discreditable conduct" may risk a jury speculating, potentially to the prejudice of the accused, about what conduct of that description the accused may have engaged in.

44. [509]

    It is apparent that care is needed whenever a trial judge directs a jury in relation to post-offence conduct from which an inference of consciousness of guilt may arise. There is a need to be wary that any hypothetical explanation given is one that might reasonably arise from the facts and circumstances of the case.

45. [510]

    A further difficulty with a trial judge giving hypothetical explanations to a jury arises in cases where the accused provides an actual explanation. Trial judges need to be careful not to diminish the force of, or detract completely from, the explanation relied upon by the accused. There is a risk that where the actual explanation is something quite specific and unique, it may be made to sound absurd if a judge were to suggest that people in general might behave in the same way. There is also a need for a judge to avoid any appearance of becoming an alternative advocate for the defence.

46. [511]

    There is no issue about the trial judge having reminded the jury of the actual explanation advanced by the appellant for his destruction of the shoeboxes. Her Honour did so in quite some detail, while also pointing out that it was not for the appellant to prove anything. The essence of counsel's closing submissions was summarised at the outset of this passage of the summing up: [883]

47. [512]

    The appellant raised no complaint about the adequacy or accuracy of the trial judge's review of his explanation for destroying the shoeboxes. The complaint in relation to this issue, and in relation to the Plan B issue, was the failure of the trial judge to point out the hypothetical explanations there may be for an innocent person to have acted in those ways, relying upon the second paragraph of the above extract from Edwards v The Queen.

48. [513]

    There was no complaint about the extensive general directions given by the trial judge about inferential reasoning and circumstantial evidence. Nor was there any complaint about any other aspect of her Honour's directions specifically directed to the inferences of consciousness of guilt the Crown said arose in relation to the shoebox and Plan B issues.

49. [514]

    It is evident from the written directions [884] which have been set out in full earlier that the trial judge gave the jury in clear terms the essential direction required by Edwards v The Queen, that is to say that the conduct in question "cannot rationally be explained other than by the accused's self-conscious awareness that he had murdered the deceased". Her Honour also put it the other way around in directing that if the conduct "might reasonably be explained for reasons unrelated to a self-conscious awareness of guilt (etc) then you could not draw the inference that the Crown contends for".

50. [515]

    When dealing directly with the shoebox destruction issue, the trial judge commenced by describing the Crown's submission as being that "there is no rational innocent explanation" for the conduct other than a belief by the accused that evidence of the shoeboxes would incriminate him. [885] This reinforced the direction she had previously given orally and in writing, that it was a mandatory prerequisite for the evidence to be construed in the way the Crown contended and that there be "no rational innocent explanation". The case for the appellant was that such an explanation existed and the jury was reminded of it: "the accused's conduct in destroying the shoeboxes you would consider as not supporting an inference of guilt, but as a response to being falsely accused of murder".

51. [516]

    The direction it is now suggested the trial judge should have given includes that "people do not always act rationally" and the possible alternative explanations for destruction of the shoeboxes were "panic" or "to escape an unjust accusation". As just noted, however, escaping an unjust accusation was the accused's actual explanation so it could not have been given as a hypothetical one. "Panic" could only be pertinent if it was the cause of the appellant wanting to escape an unjust accusation, so that did not add anything and the suggestion that "people do not always act rationally" does not sit comfortably with the actual explanation; a deliberate, considered attempt to avoid an unjust accusation. Characterising it as rational or irrational would not have been helpful.

52. [517]

    In relation to the Plan B issue, again the trial judge directed the jury in direct terms that they must "consider whether the accused's words and conduct might be rationally explained for reasons inconsistent with displaying an awareness of his guilt". [886] Her Honour proceeded to summarise the dispute between the parties as to the factual elements of this issue. [887] Her Honour concluded by referring the jury back to her general directions on the subject of consciousness of guilt, including the written directions. [888]

53. [518]

    The direction it is now suggested the trial judge should have given again includes that "people do not always act rationally" and the possible alternative explanations are "fear" or "escape an unjust conviction". The suggestion of irrationality does not fit well as a possible explanation for conduct that comprised several components and occurred over a period of time. No actual alternative explanation was advanced in the defence case, no doubt because the conduct in the respects relied upon by the Crown was disputed. No hypothetical alternative explanation was suggested to the jury by the trial judge. The hypothetical explanation the appellant suggested in this Court should have been given by the trial judge, would have had a real tendency to undermine the defence case of denial of the primary conduct. We accept the submission by the Crown that this was a judgment call best left to be made by those in tune with the atmosphere of the trial, namely counsel and the trial judge.

54. [519]

    The summing up was delivered over eight days. During the many breaks during those days, and often at the beginning or the end of days, counsel for the appellant rose to seek clarification, correction or augmentation of the directions that were being given. This suggests that if he considered that there was any disadvantage accruing to his client about any of the directions her Honour was giving, including about consciousness of guilt, he would have raised the matter with her. The only instance of counsel raising a point about consciousness of guilt and Witness A, to which her Honour responded, and counsel replied, was the following: [889]

55. [520]

    Her Honour subsequently gave that direction and she repeated the essence of it in a wrap up at the very end of the summing up. [890]

56. [521]

    The absence of any request by counsel for further directions in relation to both issues raised under Ground 5(a) tends to indicate no unfairness or injustice was perceived on behalf of the appellant.

57. [522]

    We are satisfied that the directions given by the trial judge were both adequate and appropriate in all the circumstances.

58. [523]

    Leave to raise Ground 5(a) is refused.

59. [524]

    Ground 5(b) involves the contention that “a miscarriage of justice resulted from the direction given to the jury in relation to the appellant's alleged consciousness of guilt, in particular … (b) the summary of relevant factual matters was unbalanced in favour of the Crown”. The “relevant factual matters” were various aspects of the appellant's conduct on 18 July 2009. In the appellant’s first written submissions it was said that they "were so finely nuanced that they required careful explanation of all the relevant evidence to place the Crown contentions in perspective, and this did not occur". [891] In a second tranche of written submissions it was said that “because the evidence relevant to the conduct on 18 July 2009 was expansive and diffuse, it takes a long while to set it out – although this did not occur in submission or direction to the jury, which the [appellant] alleges to be the problem”. [892] Almost 100 pages followed in the second and in a third tranche of submissions.

60. [525]

    Before proceeding further into this ground, it is worth observing the requirements of a summing up as explained by the plurality of judges of the High Court of Australia in McKell at [35]:

61. [526]

    The Crown drew attention to a passage in the joint judgment of six judges of the High Court in Domican v The Queen (1992) 173 CLR 555 at 560-561; [1992] HCA 13 (part of which was referred to in McKell v The Queen above) that is very pertinent to this ground. The Crown summarised the passage as involving the following propositions: [893]

62. [527]

    As with Ground 5(a), the complaints raised under this ground were not raised at trial. Further, and as the Crown pointed out, the summing up by the trial judge came at the end of a very lengthy trial with cases put by the Crown and the defence on particular bases. The closing addresses themselves were lengthy (the Crown's on Days 87 to 91 of the trial and the defence address on Days 92 to 103).

63. [528]

    The appellant contrasted his complaint in relation to the way the trial judge reviewed the evidence of his alleged conduct on 18 July 2009 with the way her Honour put to the jury the two matters the subject of complaint under Ground 5(a). He submitted that the "protective component of an Edwards direction was not by analogy applicable or appropriate for this body of evidence" but that "it was necessary … for the jury to be reminded by her Honour in a neutral fashion of the evidence relevant to the contentions sought to be advanced by the Crown". [894]

64. [529]

    The appellant submitted that in asking the jury to draw inferences of consciousness of guilt in relation to his conduct on 18 July 2009, "the Crown case relied on tenuous interpretations of evidence, tenuous reasons for rejecting Kathy Lin's evidence, disregard for other important aspects of the evidence, and lack of regard for the complexity of the horrific circumstances faced by the [appellant] and his wife on the morning of 18 July 2009". Further, the appellant submitted: [895]

65. [530]

    As can be seen, the contentions raised under Ground 5(b) are more concerned with whether the summing up was fair and balanced than with any technical or legal aspect of how the jury was directed as to the Crown’s reliance upon consciousness of guilt inferences.

66. [531]

    The Crown addressed the jury about various aspects of the appellant’s actions on 18 July 2009. [896] According to the appellant's submissions, there were seven aspects of such conduct that were alleged to demonstrate consciousness of guilt. [897] They were identified in the submissions as Topic A to Topic G, most of which are discussed below. “Topic F” requires no discussion as it is not relied upon in support of Ground 5(b). [898]

67. [532]

    This is the first topic that is the subject of complaint. Contrary to other “Topics” referred to under Ground 5(b), and confusingly having regard to it appearing under this ground, the contention here is not that the summing up was unbalanced and unfair. It involves a complaint about the trial judge not having directed the jury not to use the evidence concerning this topic as capable of giving rise to an inference of guilt.

68. [533]

    Drawing from the Crown address, it was the Crown case theory that the appellant had anticipated that somebody else would discover the bodies after Min Lin did not turn up at the newsagency at his usual time to organise newspaper deliveries. However, telephone calls were made to Kathy Lin by persons concerned that the newsagency had not opened as usual. She then decided that they would drop by her brother’s house on the way to McDonalds where they intended to have breakfast before going shopping. The Crown Prosecutor said that the appellant “would have realised with some dismay at that point that there was no choice: he and Kathy were going to be the ones to discover the bodies”. [899]

69. [534]

    The Crown Prosecutor reminded the jury that in a conversation with Witness A on 19 May 2012, the appellant spoke of some notion that the first person who enters the crime scene is "more than half chance, that's the killer … that's the statistics". A little later, Witness A said, "[i]t's better for you if somebody else find the bodies" and the appellant replied, "[o]f course … I don't have much trouble then". [900] The Crown Prosecutor reminded the jury of the appellant saying, “one old man, Chinese man … don’t call police” (a reference to a person who called Kathy Lin rather than the police), “that man make me in trouble”. [901] The conversation with Witness A was the basis of the Crown submission to the jury mentioned above, that the appellant would have been dismayed to realise that there was no choice; he and Kathy Lin were going to be the ones to discover the bodies. [902]

70. [535]

    The Crown Prosecutor concluded by submitting: [903]

71. [536]

    Later, in the context of addressing the subject-matter of what is now referred to as “Topic E” (leaving Kathy Lin at Boundary Road), the prosecutor tied the motivation for the appellant leaving the scene at Boundary Road to his concern about a police investigation being imminent giving rise to a need to get rid of incriminating evidence. The submissions included: [904]

72. [537]

    It is notable that the Crown did not submit that the jury should draw an inference of guilt based upon the subject-matter of Topic A on its own.

73. [538]

    The appellant accepted that the trial judge only referred to the evidence on this subject while dealing with other matters. Her Honour did not direct the jury that it was a matter relied upon by the Crown as a circumstance indicating guilt. [905] In the course of discussing the matter her Honour said:

74. [539]

    The trial judge also referred to the Crown’s submissions about the conversation with Witness A regarding calls being made to Kathy Lin on the morning of 18 July 2009, specifically mentioning the “old man didn’t ring the police but rung Kathy Lin instead, he [the appellant] said to Witness A, ‘That old man’ got him into trouble”. [906]

75. [540]

    The trial judge reminded the jury of a defence submission concerning the appellant leaving his wife at the scene at Boundary Road; his conduct was to be explained by his concern to go and get his parents-in-law, and not to avoid being on the scene as the person who would become then the prime suspect. [907]

76. [541]

    The above are the only matters in the summing up to which the appellant’s submissions referred.

77. [542]

    The appellant’s complaint in relation to Topic A is that the Crown relied upon the evidence as supporting an inference of consciousness of guilt whereas the evidence was incapable of bearing that character. [908]

78. [543]

    The appellant accepted that the trial judge did not direct the jury that his alleged dismay at having to discover the bodies of the deceased was a circumstance indicating guilt. The problem was that the trial judge did not direct the jury that the evidence could not be used as supporting such an inference as the Crown had contended. [909]

79. [544]

    It was acknowledged that no complaint was raised at trial and that r 4 of the Criminal Appeal Rules applied. [910]

80. [545]

    Topic A may not have been the strongest element of the Crown case as to the availability of inference of consciousness of guilt, but when considered with the other topics, as it was in the summing up, the evidence was not incapable of supporting such an inference. The undisputed evidence was that the appellant and his wife were put into a position where it became necessary for them to attend the Boundary Road home on the morning of 18 July 2009. This had the inevitable consequence that they would be the first to discover the bodies of the deceased. The significant issue for present purposes is that three years later, in a conversation with Witness A, the appellant expressed dismay at having been forced into this position because it possibly gave rise to a perception of criminal responsibility for the deaths. While it may be capable of bearing other inferences, it was also capable of being regarded by the jury as a sign of the appellant being concerned on account of his knowledge that he was in truth criminally responsible.

81. [546]

    There is also force in the Crown submission that the trial judge dealt with Topic A as being a subsidiary matter informing Topic E. The jury was not directed that it was a matter that gave rise to an inference of guilt on its own. Viewed in this way, it was only a quite small part of the Crown’s overall circumstantial case. This is illustrative of the interconnectedness of the circumstantial case. This matter was one of a series of actions by the accused on 18 July 2009 that the Crown relied upon. A direction was not required to be given by the trial judge as to whether individual components of that case could, on their own, support an inference of guilt.

82. [547]

    There was no requirement in relation to Topic A for the trial judge to direct the jury not to draw an inference adverse to the appellant and trial counsel cannot be criticised for failing to ask for such a direction.

83. [548]

    The Crown reminded the jury in closing that the appellant had told police in his 22 July 2009 interview that when he arrived at the Boundary Road home on the morning of 18 July 2009 with his wife and their son, XX, he told XX to stay in the car. The Crown submitted that this was because he did not want his son to see what was inside the home. He told him to stay in the car “because he knows what is waiting inside. … he had to avoid [XX] running in, trying to find his cousins and stumbling across the horror of what was upstairs waiting”. [911]

84. [549]

    The Crown also reminded the jury that Kathy Lin had claimed to have been the one who told XX to wait in the car. It was submitted that she was giving evidence in a way that helped the appellant. She “could not bring herself to say in evidence anything that she perceived could potentially be used against her husband”.

85. [550]

    Counsel for the appellant submitted to the jury that they would not take this into account against him. There was nothing remarkable about telling XX to stay in the car given they were on their way to McDonalds on a Saturday morning. [912]

86. [551]

    At the beginning of the section of the summing up where the trial judge dealt with evidence the Crown relied upon for an inference of consciousness of guilt, her Honour very quickly summarised the topics the Crown relied upon. Her Honour referred to five of the seven topics now the subject of complaint; one she did not refer to was Topic B. [913] Telling XX to stay in the car was referred to elsewhere, but only in passing and in the course of referring to the sequence of events that occurred. [914]

87. [552]

    It was submitted that the evidence of telling XX to stay in the car was "entirely immaterial and of no probative value". Further, "the summing up should have raised for the jury's counter consideration to the Crown contention of consciousness of guilt ... the explanation that this was an entirely banal parental decision, consistent with the intention of both parents and their child to get to McDonalds breakfast as soon as possible". [915]

88. [553]

    The appellant’s written submissions in relation to this evidential topic commenced by describing it as a “relatively minor one”. [916] There is no question about that. It was not treated by the Crown as an event that by itself could support an inference of consciousness of guilt. Rather, it was an event that formed part of the sequence of actions of the appellant on 18 July 2009 that the Crown relied upon in its circumstantial case.

89. [554]

    The trial judge said enough to remind the jury of the defence case:

90. [555]

    The lack of any application for further direction on the subject is unsurprising.

91. [556]

    As summarised by the appellant, Topic C is concerned with a contention by the Crown that the appellant “grabbed hold of his wife and told her not to look from a position near the entry to Bedroom 1 where he could not possibly have seen the bed, thus demonstrating his knowledge of the horrible vision from which he tried to protect her, because he had caused it”.

92. [557]

    In contrast to Topic B, this Topic does not involve a complaint of the defence case not having been put; the appellant conceded that it was. The complaint was encapsulated at the hearing as follows: [917]

93. [558]

    The appellant’s written submissions provided a very extensive review of the evidence, the closing address by the Crown and the trial judge’s summing up. The review of the evidence included that of Kathy Lin, the police interview of the appellant on 22 July 2009, a covertly recorded conversation between the appellant and Kathy Lin on 29 April 2010, and sundry oral and physical evidence. [918]

94. [559]

    "Bedroom 1" was the crime scene designation of the main bedroom where the bodies of Min and Lily Lin were found. They were found lying at an angle with their feet in the middle lower end of the bed and heads on their respective sides of the top of the bed. The body of Min Lin could not be seen because it was completely covered by bed clothes. (That is a matter relevant to Topic G.)

95. [560]

    To understand the evidence that is referred to below it is necessary to note that the bed, especially the pillow end, was not visible to a person standing in the doorway. If a person turned 90 degrees to the right upon entering the room, a children’s bed was against the wall to the person’s left, a chest of drawers was against the wall straight ahead, and the deceased couple’s bed was to the person’s right. (See the diagram provided earlier. [919] )

96. [561]

    The Crown Prosecutor reminded the jury they had the benefit of attending views of the Boundary Road home on two occasions and: [920]

97. [562]

    The jury also had the benefit of still photographs and what were described as “a crime scene video so there was a walk-through video and a 3D reconstruction and a 3D representation of the crime scene". [921] The jury must have been well and truly acquainted with the Boundary Road home, sufficient to assist with determination of the facts in relation to the many disputed issues, including what the appellant has now designated Topic C.

98. [563]

    The appellant and his wife discovered the murder scene when they attended the Boundary Road home on the morning of 18 July 2009. The bedrooms were all upstairs and the first one they went to was Bedroom 1. Kathy Lin led the way; she went through the doorway first. At a certain point (which is controversial), the appellant hugged her and told her not to look.

99. [564]

    In July 2009, the appellant told police that he followed his wife into the room. He said he saw the body of his sister-in-law and "everywhere is red". Once he saw that, he held his wife and told her not to look, but he believed that she had already seen. [922] In March 2010, he told police that his wife had proceeded into the room, "I'm not sure, two metre" and he was "one metre – I'm not sure anyway, not far away". [923]

100. [565]

     Topic C concerns the Crown's reliance upon something Kathy Lin told the police in her July 2009 interview [924] that was inconsistent with the above account by the appellant. Based upon what she said, the Crown submission to the jury was that the appellant, being behind Kathy Lin, would not have been able to see the bodies of Min Lin and Lily Lin because Kathy Lin had only just entered the room: [925]

101. [566]

     The Crown relied upon Kathy Lin's initial account in her July 2009 interview to make good this point (see [22]). It therefore had to negate the contrary evidence she gave before the jury, which was to the effect that she was sufficiently inside the bedroom that the appellant would have been able to see the murder scene on and around the bed. The Crown contended that this was “another topic where [Kathy] Lin, when she was giving evidence before you, was clearly not being truthful”. The Crown also referred the jury to what it contended were inconsistencies in the versions given by Kathy Lin in her interviews on 20 July 2009 and 22 March 2010. [926]

102. [567]

     Kathy Lin's evidence before the jury was that upon entering the room she went to "about the end of the bed". Then her husband "told me not to see but I already saw everything … I saw dead bodies". When asked for clarification of what the appellant said she replied, "He asked me not to see and he hugged me tightly … He said, 'Don't look'". Although she had said that he had followed her into the room, she said that when he hugged her tightly, "he's beside me". [927]

103. [568]

     In her interview with police on 22 March 2010, Kathy Lin was asked questions by police about entering Bedroom 1; relevantly: [928]

104. [569]

     The Crown Prosecutor reminded the jury that, shortly after those questions and answers, Kathy Lin was asked to mark on a diagram "as best she could" where she was standing when her husband grabbed her and told her not to look. She spoke in Mandarin to her solicitor, saying "I cannot point out where it was". She added a moment later, also in Mandarin to her solicitor: [929]

105. [570]

     The diagram she was being asked to mark had a rather poor quality representation of the layout of rooms. [930] However, if it was the truth that she was "about the end of the bed", the jury might have thought that the question was not impossibly difficult. Moreover, the jury might have recalled her explanation in her trial evidence that the reason she did not mark the diagram was because her solicitor told her that she did not have to. It might have also prompted the jury's recall of Kathy Lin's equivocation at that point of her evidence when pressed to explain why she said "a little bit" in the answer to Q268 on 22 March 2010. [931]

106. [571]

     The Crown Prosecutor contrasted this with her evidence before the jury in which she was able to mark on a diagram exactly where they were standing. She marked a location about halfway between the doorway and the bed; significantly, a position where both would have been easily able to see the bed and the horrific scene on and around it. [932]

107. [572]

     As noted, in her July 2009 interview Kathy Lin gave the following account while gesturing, as indicated in the following extract from the Part A Summary of Trial. [933] The appellant accepted that Kathy Lin made a turn to her right, "something that is no greater than 90 degrees, perhaps up to a 90 degree turn or something less than that". [934]

108. [573]

     Kathy Lin gave the same description, orally and with consistent gesturing, a little later in that interview:

109. [574]

     Kathy Lin was cross‑examined about her evidence in the 2015 trial in which she had been shown the footage from her July 2009 interview in which she answered Q 1856 above (ie, [572]). The footage was replayed for her. At the 2016 trial she agreed that she had said in 2015 that she only saw her sister-in-law's body after her husband had hugged her from behind and told her not to look. She agreed that this was a truthful answer. [935] But when asked at the 2016 trial to confirm that she only saw her sister-in-law after her husband hugged her and told her not to look, she said: [936]

110. [575]

     The cross‑examiner at the 2016 trial reminded her that she had said twice at the 2015 trial that she saw her sister-in-law after the hug and warning. The portion of the July 2009 interview containing the second instance was then played for her and she agreed that she had given the answers as recorded. However, she then explained:

111. [576]

     Apart from how far into the room she and the appellant were and whether she turned before or after her husband hugged and warned her, Kathy Lin had also given different descriptions of where her husband was at the time of the hug. In her July 2009 interview Kathy Lin said he was "behind her" (and she gestured by pointing over her shoulder), while in her 2016 trial evidence she said he was, "beside me".

112. [577]

     The Crown also relied upon a covertly recorded conversation between the appellant and his wife on 29 April 2010. It contended that it involved the appellant being aware that police were interested in where they were standing when they entered Bedroom 1 and he was “coaching” Kathy Lin as to what to say. [938] The conversation occurred two days after she had been served with a summons to attend at the NSW Crime Commission. The recording and a transcript were before the jury. It was well open to the jury to accept the Crown's characterisation of the conversation as involving “coaching”. For example, it included: [939]

113. [578]

     Kathy Lin was cross‑examined by the Crown about this conversation. She gave an innocent account of it, including that she and the appellant were having the conversation because they were worried about the possibility of the police framing them. [940]

114. [579]

     The trial judge gave general directions about the drawing of inferences as to consciousness of guilt and then dealt with individual matters that the Crown relied upon in that respect. The first item dealt with was the entry of the appellant and Kathy Lin to Bedroom 1. [941]

115. [580]

     Her Honour reminded the jury of the Crown’s contention in relation to the issue, including reference to the Crown’s reliance upon what Kathy Lin said in her July 2009 interview. Her Honour told the jury what was and was not in dispute. Although the trial judge had already directed the jury orally and in writing, her Honour nonetheless repeated her direction that the task of making findings of fact was a matter for the jury. Her Honour provided a summary of the submissions that had been made in relation to this issue by the appellant’s counsel. [942]

116. [581]

     The jury was reminded (again) that the accused bore no burden of proof. There was another reminder that in order to draw the inference for which the Crown contended it was necessary to discount any reasonable alternative explanation for the appellant’s conduct. After immediately repeating the essence of that direction, her Honour told the jury that if they found in favour of the Crown, they could add this matter to the Crown’s overall circumstantial case. Finally, seemingly as an afterthought, the trial judge added reference to the covertly recorded conversation between the appellant and Kathy Lin on 29 April 2010 and reminded the jury of the Crown submission that it was a “rehearsal of the circumstances in which they came upon the bodies in Bedroom 1”. [943]

117. [582]

     The appellant’s extensive written submissions on this Topic were helpfully digested into the following points at the hearing. [944]

118. [583]

     It was submitted that there was an imbalance in the summing up. This arose from “the context [being] given by the way the Crown had framed its case [with] an absence of any reference to what the evidence actually was, other than the fact that the Crown submission was that there were wildly divergent accounts, [together with] the absence of reference to the evidence of the accused”. [949]

119. [584]

     The appellant accepts that there was no complaint at the 2016 trial about the judge’s treatment of Topic C.

120. [585]

     The appellant contended that “the only potential inconsistency between Kathy Lin’s evidence at trial and in her interview on 20 July 2009 was whether she turned to the right after her husband hugged her”. [950] There was, however, more inconsistency than that:

121. [586]

     These matters, coupled with the “potential inconsistency” that the appellant concedes (turning to the right before, or after, the hug) provided a basis for the Crown’s submission to the jury that there was substantial inconsistency between the version Kathy Lin provided in the July 2009 interview and those she subsequently advanced. As the Crown submitted in this Court, there may have been less force in the submission if there were only Kathy Lin’s verbal accounts to compare, given her persistent claim that her account in the July 2009 interview could be unreliable because of her poor English language skills. However, it was open to the jury to consider that the gestures she gave during the July 2009 interview diluted the force of that excuse considerably.

122. [587]

     The extent by which Kathy Lin had entered the bedroom was fundamental to the Crown’s proposition that the appellant hugged his wife and told her not to look at a point at which he was not able to see the bodies on the bed. As the trial judge described it, the inference for which the Crown contended was that “in that moment as a matter of impulse, he sought to deflect his wife from what he knew was there to be seen”. [955]

123. [588]

     The appellant contends that, if Kathy Lin was able to see the body of Lily Lin, either before or after she was hugged by her husband, he must have been able to see the body as well. The one does not necessarily follow the other; it very much depends upon how far into the room they had progressed. It must be borne in mind that the pair were unlikely to have been stationary when the hug occurred, and it was open to the jury to accept that the appellant was behind Kathy Lin. (The appellant said in his police interview in March 2010 that he was “a few steps” or “one metre … not sure … not far” behind Kathy Lin. [956] )

124. [589]

     It was also open to the jury to accept that the appellant and Kathy Lin had rehearsed a version in the covertly recorded conversation on 29 April 2010, two days after she had been served with a NSW Crime Commission summons. The jury could have regarded it as damaging to the credibility of a proposition that if she could see the body of her sister-in-law then he would have been able to as well, given this conversation included the appellant telling his wife: [957]

125. [590]

     Whatever view one might take about the strength of the Crown argument in relation to this issue, it was a tenable argument, given the state of the evidence. There was a real controversy; not a “constructed” one.

126. [591]

     This ground concerns the way the trial judge directed the jury. The structure of the summing up on this issue has been described earlier. We do not perceive any lack of balance or unfairness. The trial judge summarised the competing cases and reminded the jury of relevant aspects of their task in finding facts and drawing inferences. The latter included that if there was any alternative reasonable explanation for the appellant’s conduct the inference for which the Crown contended could not be drawn. Her Honour reminded the jury of the Crown bearing the burden of proof, with the accused not being required to prove anything.

127. [592]

     There was the one discrete complaint, faintly raised, that the trial judge referred to the appellant’s answers in a police interview but did not remind the jury what they were. The short answer to that is that the trial judge was not purporting to engage in a detailed review of the evidence. It was enough to remind the jury as her Honour did. In relation to this, and Topic C overall, it is significant that her Honour was not asked to correct or to augment her directions in any respect.

128. [593]

     The trial judge did not include this Topic when surveying the various activities of the appellant on 18 July 2009 in the context of dealing with consciousness of guilt matters. [958] Her Honour had, however, briefly referred to this earlier in the summing up when outlining matters that formed part of the Crown’s circumstantial case and her Honour referred to it again at the end within a very condensed summary of the Crown case. [959]

129. [594]

     This Topic is concerned with a short point: the appellant made no real attempt to check whether either of the two boys were still alive because, as the murderer, he knew they were dead. The bodies of the boys were in Bedroom 3, the last of the bedrooms entered by the appellant and Kathy Lin.

130. [595]

     The Crown suggested to the jury that the bodies of the two boys were not in such a state as to discourage a medical professional from checking for signs of life; indeed, the ambulance officers checked to see if they had a pulse. The appellant was medically trained, [960] and he had a close relationship with the boys. The Crown referred to passages in the appellant’s police interviews. On 22 July 2009, the appellant told the police: [961]

131. [596]

     Later in the same interview he said he “possibly” touched the children’s necks. [962]

132. [597]

     In his interview on 16 March 2010, the appellant said he “want[ed] to try to touch them and see if they … were alive”; he may have attempted to touch the older of the two boys, but “I forgot”. [963]

133. [598]

     The crux of the Crown submission was: [964]

134. [599]

     Defence counsel addressed this issue on at least five occasions during a 12‑day closing address to the jury. It was suggested that it was obvious that all the deceased were dead at the time the appellant saw the bodies so that this issue was “completely neutral”. Ambulance officers immediately recognised that the deceased were dead so this was not something the jury would hold against the appellant on the question of his guilt. It was submitted that the Crown case “needs to be closely examined, and … utterly rejected” as “it was obvious that those persons were deceased and would have been … more obvious to a medically trained person”. This was equally obvious in relation to the children and so it was not something the jury would consider against the appellant. The jury was reminded that one of the first police officers to attend the scene agreed that it was “very obvious” that the people he saw were deceased. [965]

135. [600]

     Defence counsel made short submissions on several points at the conclusion of his address. This included asking the jury to bear in mind the appellant must have been in a state of shock having witnessed the scene upstairs. He also reminded the jury of what Kathy Lin said in her July 2009 interview, including that the appellant had wanted to check whether the boys were still alive, but she had told him not to. [966]

136. [601]

     As indicated earlier, this Topic was not included in the consciousness of guilt section of the summing up. It was mentioned earlier, and only briefly, as being a component of the Crown’s circumstantial case. In the middle of nominating the various components of that case her Honour said: [967]

137. [602]

     In a wrap-up summary of the Crown case shortly before the jury retired, her Honour said: [968]

138. [603]

     There were no other references to this Topic in the summing up.

139. [604]

     The appellant contends that that the trial judge "failed to address this issue with the balance required" by overstating the Crown contention and by referring to none of the evidence regarding the attempts the appellant did make to check on the children. [969]

140. [605]

     In oral submissions, the contention of there being an “overstatement” by the trial judge was clarified: the Crown had addressed the jury on the subject of checking on the boys in terms of the appellant having made “no real attempt”, whereas the trial judge simply said “no attempt”. [970]

141. [606]

     It was also submitted that the trial judge should have reminded the jury of several aspects of the evidence that favoured the defence in relation to this issue. They were matters that neither party had referred to in submissions on this issue. [971]

142. [607]

     Dealing with the last point first, it is not the case that a trial judge has a general and overarching obligation to refer to evidence that favours one party or the other that has not been the subject of submissions, or mentioned at all, in closing address by the parties themselves. We have earlier referred to Domican v The Queen and McKell v The Queen. The following statement from Whitehorn v The Queen (1983) 152 CLR 657 at 682; [1983] HCA 42 (Dawson J), as paraphrased in McKell, is directly on point in responding to this aspect of the appellant’s criticism of the trial judge:

143. [608]

     The difference between “no real attempt” and “no attempt” is insignificant in the circumstances. Defence counsel did not apply any qualifying word when referring to the issue in his address. He spoke of “[the appellant] not checking the children”. [972] On any view, the appellant made no effective attempt to check whether the boys were still alive. Either description was apt.

144. [609]

     There was nothing unfair or lacking in balance in her Honour’s treatment of this issue. The relative lack of significance of the point is indicated by the brevity with which it was dealt. There was no complaint raised by trial counsel. To the extent that the appellant relies upon a cumulative effect of the various Topics raised under Ground 5(b), this one adds nothing.

145. [610]

     The Crown contended in its closing address that, soon after exiting the Boundary Road home, the appellant left his wife there and drove away. He was absent for the next hour or so. This was after the discovery of the horror within when it was supposedly unknown whether the killer was still present. The Crown argued that leaving in such circumstances was against the wishes of his hysterical, distressed and fearful wife.

146. [611]

     The appellant first took XX to their home nearby in Beck Street. He then drove back to Boundary Road where he spoke briefly to his wife. He then drove to Merrylands where he picked up the grandparents and brought them back to North Epping. The Crown contended that he took the opportunity to dispose of incriminating items including the murder weapon. It contended that he implicitly admitted this was his purpose in the covertly recorded conversation he had with Witness A on 13 October 2012 [973] noted above (at [63]).

147. [612]

     The defence case, according to the appellant’s written submissions in this Court, was that there was nothing abnormal about the appellant leaving his wife; there was inadequate time to dispose of any incriminating items; and there was nothing found in the car to indicate incriminating items had been in it. Senior Counsel for the appellant was critical of trial counsel for being inconsistent in submissions about the evidence of Kathy Lin’s father in connection with this issue. There was also criticism of the failure to make submissions in relation to the Crown’s contention that an implied admission was made in the conversation with Witness A on 13 October 2012. [974]

148. [613]

     Senior Counsel for the appellant submitted at the hearing of the appeal that “the strong and clear inference to be drawn from the evidence is that the [appellant] left his wife because his wife wanted him to go and pick up her parents”. [975]

149. [614]

     The appellant's contention in relation to Topic E is essentially a complaint about imbalance favouring the Crown.

150. [615]

     The closing address for the Crown on this subject included a detailed review of the evidence it regarded as relevant. That review was interspersed with the following submissions.

     1. (1)

        Kathy Lin did not want her husband to leave when he did. He nevertheless abandoned her. Eyewitness accounts confirmed this. [976]

     2. (2)

        The appellant had no concerns about leaving his wife at the scene. This was because he knew she was not at risk of any harm because he was the person responsible for the murders. He did not need to be worried about her safety. [977]

     3. (3)

        What was so pressing that the appellant was prepared to leave his distressed wife? Her distress was evident from the triple-0 calls that the jury had heard. She was very scared and telling him not to go. His pressing need was to dispose of the incriminating evidence that he had collected from Beck Street when he took XX back home. He was fearful that the police may decide to commence their investigations into him that day because he was one of the people who had discovered the bodies. He could not run the risk of anything linking him to the crime scene being discovered by police. [978]

     4. (4)

        The real reason the appellant left his wife at Boundary Road on her own emerged from the conversation he had with Witness A on 13 October 2012. He implicitly admitted that there “may be” some CCTV footage of him disposing of the hammer on the way to the grandparents. If he did not dispose of a hammer, why would he be concerned at all about CCTV? [979]

     5. (5)

        The defence may submit that the trip to pick up the grandparents did not take any longer than usual. By way of response, it would not have taken very long on the way there to dispose of the incriminating items. [980]

     6. (6)

        The defence would rely on the fact that police found no blood in the car the appellant used. That is explained by the fact the items must have been covered with some sort of protective covering, like a bag.

151. [616]

     The Crown’s concluding submission was: [981]

152. [617]

     The appellant’s written submissions included a summary of relevant aspects of the defence closing address on this subject:

153. [618]

     The appellant's primary complaint according to the written submissions appears to be, "[t]he real defence case was never left for the jury's consideration". At the hearing, the complaint was described as there having been an over-emphasis of the Crown case and an inadequate treatment of the defence case. [982]

154. [619]

     The submissions by the appellant were extensive and ranged widely with criticisms of the Crown case and how it was argued in closing address, including assertions as to how it might or should have been argued, as well as criticisms of the trial judge’s summing up.

155. [620]

     The "real defence case" was identified as: "[t]he [appellant] went to collect his wife's parents with Kathy Lin's active encouragement – to support her as she wished to be supported in this moment of trauma". [983]

156. [621]

     The written submissions for the appellant continued with arguments as to why it should be accepted by this Court that the defence case was as described. This is unusual. A criminal appellate court is entitled to accept that a party's case was as it was presented in the court below. It is not a matter for the court to determine that a party's case was something that is based upon the court's own assessment of the evidence, guided by submissions of the party on the appeal that differ from those which the party made below.

157. [622]

     Nonetheless, this is what the Court was asked to do. It was then asked to determine whether the trial judge put the case for the appellant to the jury in accordance with what has been determined to be his case by this Court (cf Domican v The Queen at 560-561). The following paragraph from the appellant’s written submissions is illustrative of the approach:

158. [623]

     It is readily apparent that this emotive advocacy is a plea for this Court to make a finding in relation to the evidence. It is not a statement of what the defence case was. Even less is it a statement of something that was a significant part of the defence case as put to the jury by defence counsel but was not referred to in the trial judge's summing up.

159. [624]

     Bearing in mind that this ground is concerned with asserted error in the summing up, the following may be identified as submissions pertinent to that aspect:

     1. (1)

        Neither counsel nor the trial judge reminded the jury of Kathy Lin having said in her July 2009 interview: “I said you need to let my mum, my parents know so you, you quick. First, I say, I let mum catch the train and he, I change it, I said, you, you, you go to my mums home, pick up them quicker they catch the train so my husband left and ring, and the, the triple-0 again”. [984]

     2. (2)

        Neither counsel nor the trial judge reminded the jury of the appellant saying in both his police interviews that he went to collect Kathy Lin’s parents in accordance with her wishes. The trial judge was required to remind the jury of this in putting the defence case on this issue. [985]

     3. (3)

        Neither counsel reminded the jury of evidence about the conversation between the appellant and Kathy Lin when he came back to Boundary Road after having dropped XX home at Beck Street. There was an exchange between them as to whether her parents should be asked to come by train but they settled on the appellant going to collect them. The trial judge referred to this in the summing up but only to suggest why it was wrong. [986] (That is not correct. The trial judge simply reminded the jury that the Crown had submitted that it was contradictory for Kathy Lin to say the appellant left when they had agreed he would pick the grandparents up, rather than them catching public transport, when after driving off the appellant rang the grandparents and spoke about the prospect of them catching the train). [987]

     4. (4)

        It was inappropriate for the trial judge to have repeatedly informed the jury that it was the Crown case that there was “evidence of entreaties to stay, requests to stay, [or] protestations about the [appellant] leaving”. [988]

     5. (5)

        The trial judge was incorrect in informing the jury that Kathy Lin had denied saying to the appellant, “I’m more scared than you”. The likely impact of this misstatement on her credibility was important. Kathy Lin always agreed that she said, “No, I’m more scared than you”. She simply disagreed with the Crown construction as to what it meant. [989]

     6. (6)

        Neither the Crown Prosecutor nor the trial judge mentioned that the appellant had said in an interview that he told Kathy Lin’s parents in a phone call that something bad had happened and he was going to come and pick them up. Further, Kathy Lin’s father had said that he was told something had happened and was asked if he would like the appellant to come to pick them up or catch the train. [990]

     7. (7)

        Neither counsel nor the trial judge reminded the jury of the continued contact between the appellant and his wife on his trip to Merrylands. [991]

     8. (8)

        The trial judge did not repeat the submissions by defence counsel as to the timing of the appellant’s trip to and from Merrylands, nor the evidence upon which they were based. Her Honour did, however, repeat the Crown’s counter arguments in summarising the Crown case. [992]

     9. (9)

        The trial judge suggested that the absence of forensic evidence in the car was consistent with the absence of the appellant’s DNA at the Boundary Road home, indicative of someone taking great care not to leave evidence. This was circular and a submission not even advanced by the Crown. [993]

     10. (10)

         The trial judge made no reference to the defence arguments about the safety of the environment in which Kathy Lin was located nor the evidence upon which those submissions were based. (She was located at the end of a long driveway from the home of the deceased and there were family sports activities around her.) [994]

     11. (11)

         The trial judge was in error in amplifying the Crown theory about the level of distress demonstrated by Kathy Lin in the triple-0 calls and it being indicative of her not wanting the appellant to leave her. The Crown theory was significantly disconnected from the most natural interpretation of the evidence (Kathy Lin had much to be distressed about) and the amplification of the Crown’s theory and failure to remind the jury of the defence case contributed to a miscarriage of justice. [995]

160. [625]

     The appellant was also critical of the jury having been left with a “highly unbalanced reminder of the evidence relevant to whether [he] admitted to Witness A on 13 October 2012 that he disposed of a hammer on his way to collect his wife’s parents”. He submitted, “there was so much that needed to be said about this recorded conversation”. [996] Submissions were made that were critical of arguments presented by the Crown and suggested arguments that were available to the defence. [997]

161. [626]

     As to this latter aspect, the conversation with Witness A on 13 October 2012, the appellant acknowledged that the trial judge did not have an obligation to mount arguments that should have been made by trial counsel; but that is an issue raised in Ground 8. It was, however, submitted that the trial judge should have reminded the jury that it was a matter for them to determine if the various propositions for which the Crown contended were made good. Further, the summing up “ideally” would have pointed out certain statements made by the appellant to Witness A which could be construed as exculpatory. [998]

162. [627]

     As the Crown pointed out, much of what the appellant contended should have been put to the jury as the “real defence case” turned largely upon the jury accepting the evidence of Kathy Lin. For the trial judge to have provided a balanced review of Kathy Lin’s evidence it would have been necessary to refer to various inconsistent statements she had made. This would have had a bearing upon the credibility of her evidence not only concerning this issue but also in relation to other topics upon which the appellant relied in her testimony. Two topics prominent in that vein were the appellant’s alibi [999] and the circumstances of she and the appellant entering Bedroom 1. [1000]

163. [628]

     The appellant’s submissions include an extensive argument as to what conclusion should be drawn as to Kathy Lin’s state of mind at the time she was speaking with her husband in person while also on the phone to the triple-0 operator. However, there was an alternative view to be taken based upon the tone of her voice and the content of her utterances as indicated by the recordings. The Crown submission to the jury would appear to have been one that was open to be made. Part of it was: [1001]

164. [629]

     The Crown usefully referred to matters that the appellant submitted needed to be drawn to the attention of the jury by the trial judge which were in fact drawn to its attention or in respect of which there would have been difficulties for the defence case if her Honour had done so. It will suffice to provide the following examples.

165. [630]

     The appellant contended that the trial judge made no reference to defence arguments about the safety of the environment in which Kathy Lin was located. However, her Honour said, “[t]he fact that he left his wife behind was, in counsel’s submission, to leave her behind in a safe place some distance from the crime scene and around other people”. [1002]

166. [631]

     The appellant contended that the trial judge should have reminded the jury about Kathy Lin’s evidence of a conversation, after the appellant returned to Boundary Road from having dropped XX at their home in Beck Street, in which she and the appellant first discussed her parents coming by public transport but then agreed on the appellant picking them up. However, Kathy Lin’s evidence‑in‑chief in the 2016 trial was that the arrangement when the appellant left to take XX home was for him to continue on to pick up her parents. [1003]

167. [632]

     There was also the difficulty Kathy Lin had in explaining why, after the appellant returned to Boundary Road and then drove off to pick up her parents as she (apparently) wanted, she immediately rang him. (And she had to terminate a call to triple-0 in order to do so.) First, she said that she “call him because I want – ask him to pick up my parents as soon as possible, and back to my brother’s house as soon as possible. That’s why I call him”. When reminded that she had already told him that, and pressed on why she terminated the triple-0 call and rang him, she then said, “I want him back to help me to talk with the police, ambulance officer … I want him quick, and remind him quick as soon as possible”. The proposition that Kathy Lin needed to “remind” the appellant might not have engendered confidence in her credibility. Indeed, none of this would likely have inspired the jury to accept her at her word. [1004]

168. [633]

     Reminding the jury of the appellant’s police interviews in 2009 and 2010 might not necessarily have been helpful to the defence case. His counsel might have shied away from doing so in order to avoid drawing attention to inconsistencies with known facts (such as omitting the fact he went back to Boundary Road after dropping XX home in Beck Street [1005] ) or inconsistencies with Kathy Lin’s version(s) (such as her claim that before he went to drop XX home they had agreed that he would go and pick up the grandparents [1006] ).

169. [634]

     The Crown also pointed out that the trial judge in fact drew the jury’s attention to some of the matters which supported what is now described as the “real defence case”. [1007] It is notable that her Honour immediately followed that up by reiterating her direction that the jury must only draw the adverse inference the Crown contends is open if satisfied there is no other rational explanation for the appellant leaving his wife alone to deal with police and emergency services in the state revealed by the triple-0 calls. [1008]

170. [635]

     There was nothing erroneous or inadequate about the way the trial judge dealt with the evidence of an alleged implicit admission made by the appellant to Witness A in their conversation of 13 October 2012. Her Honour referred briefly to the topic of the appellant leaving Kathy Lin at Boundary Road, in conjunction with a number of his other activities on 18 July 2009 that the Crown said gave rise to an inference of consciousness of guilt. Her Honour then gave the jury a direction about the way in which they must approach that general issue, including that inferences could only be drawn from facts the jury found to be established by the evidence. This served to direct the jury in relation to an asserted implicit admission to the necessity first to find that such an admission was in fact made. The trial judge later reviewed the evidence in relation to the Witness A conversation on 13 October 2012, but she had already reminded the jury of defence counsel’s submission that there was nothing in any of the conversations with Witness A that revealed guilt; they were simply “gaol talk”. [1009]

171. [636]

     What is contended for by the appellant in relation to Topic E are really a variety of ways in which the case might have been pursued differently by counsel and presided over by the trial judge. This Court is generally concerned more with the case as it was litigated in the trial court than with a theoretical “real defence case” that is created from the armchair of appellate counsel who did not bear the duties, responsibilities and pressures of trial counsel.

172. [637]

     There is no merit in Topic E.

173. [638]

     This topic relates to the number of bodies police were told were in the Boundary Road home. The body of Min Lin was not immediately visible because it was in Bedroom 1, on the bed but underneath a doona. The appellant was critical of the Crown theory on this subject. In assessing the validity of this criticism, it is useful first to note the evidence upon which the Crown relied in closing address and then the submissions that were made. [1010]

174. [639]

     When Kathy Lin rang triple-0 after leaving the house, she was asked by the operator whether her brother was in the house. She said that she was not sure, she did not see him.

175. [640]

     To the first police officers on the scene, Kathy Lin said, “I think my brother’s dead inside”. She explained she had been told in a phone call that her brother had not gone to work; she came over and went inside and saw her sister-in-law was dead.

176. [641]

     Two officers went inside the house and they saw four bodies. As noted, [1011] in the initial period, they considered Min Lin a suspect.

177. [642]

     Kathy Lin must genuinely have believed that there were four deceased. The telephone records showed that at 10.12am she tried to ring her brother, obviously consistent with a belief that he was alive.

178. [643]

     In the course of making inquiries about the “missing” Min Lin, police looked into vehicles registered to him. They found that a red Corolla was registered in his name; it was in fact Kathy Lin’s car and it happened to be the car that the appellant had used to drive to Merrylands to pick up the grandparents. There was some confusion when he arrived with them back at Boundary Road with police thinking that the suspect had just returned. That was cleared up quickly.

179. [644]

     The Crown Prosecutor said that the telephone records assisted in determining what time the appellant arrived back at Boundary Road because at 10.45am Kathy Lin was still trying to call him. Accordingly, he must have arrived at some time after 10.45am.

180. [645]

     The Crown invited the jury to draw the inference that the appellant must have realised from what occurred when he arrived back at Boundary Road that police were looking for Min Lin. There was evidence that the appellant did not say anything to police at that point about how many bodies there were upstairs in the house.

181. [646]

     Kathy Lin was still of the belief that Min Lin was alive. She told her parents when they arrived at Boundary Road that four people had been murdered, her sister-in-law Lily Lin, Irene Lin and the two children. Her parents asked if she had seen her brother and she replied, “No”. Kathy Lin’s mother started thinking that her son had been kidnapped and held out hope that he was still alive.

182. [647]

     So, the Crown argued, it was clear that neither Kathy Lin nor the appellant said anything to the police at Boundary Road about Min Lin being upstairs under the covers. If there had been any suggestion of that by either of them, the police would have entered the premises immediately to look, and that did not happen.

183. [648]

     The evidence of Kathy Lin’s father, Mr Lin Snr, was that while still at the Boundary Road home that morning, the appellant said, “[a]t most we could take Brenda as our adopted daughter”. That idea was rejected but the point is that adoption would not be an issue if one of the parents of Brenda Lin was still alive. The evidence of Kathy Lin’s mother was consistent with this conversation having occurred.

184. [649]

     Thus, according to the Crown, the appellant had revealed his knowledge that Min Lin was dead; something that he could not have known if he were not the murderer.

185. [650]

     Kathy Lin and her parents were taken to Hornsby Hospital by ambulance. The appellant travelled separately and arrived shortly after they did. The police were still unaware of the whereabouts of Min Lin.

186. [651]

     A Cantonese speaking nurse, Nurse Edwards, had a conversation with Kathy Lin in which the events of the morning were discussed. Kathy Lin included that when she went to her brother’s room, she saw a body in the bed and also a lump in the bed. She said, “[w]e didn’t look”. The appellant said, “[w]e couldn’t find the brother, so we think it’s the lump in the bed, but we didn’t want to look”. [1012]

187. [652]

     Nurse Edwards had commenced work at 12.30pm and saw the appellant and the others soon after. She told police about the conversation she had with the appellant and Kathy Lin who were then spoken to by police. After some time, police returned and told the family that the body of Min Lin had been found.

188. [653]

     The police account of what occurred at the hospital was that a Detective Nuttall was asking general questions about the family. She said, “[w]e need to find Min” and Kathy Lin replied, “[h]e’s in the bed at the house”. Kathy Lin was asked whether she saw him, and she replied in an insistent manner, “[t]here’s a lump in the bed where he sleeps. I went to the room, I saw the blood and the lump. I went to pull the covers down, but my husband pulled me out and say, ‘no, don’t look’”. According to DSC Wilson, who was present, the appellant did not say anything; he had the appearance of listening but was looking at the floor or the wall at the time. [1013]

189. [654]

     Police made inquiries about this information. Officers at Boundary Road were disbelieving at first, based on what they had seen in Bedroom 1. However, it was, of course, confirmed to be correct. The news was relayed back to the officers at the hospital where DSC Wilson broke the news to the family.

190. [655]

     The Crown Prosecutor referred the jury to the telephone records that showed that, even as late as 1.45pm, Kathy Lin was still trying to call her brother. The prosecutor asked rhetorically, if she was so definite Min Lin was in the bed, that he was the lump, what was she doing trying to call him at 1.45pm? What happened to make her so sure, so soon after, when talking to police that Min Lin was in the bed? [1014]

191. [656]

     The Crown invited the jury to infer that there had been some discussion between the appellant and his wife which led to the disclosure to Nurse Edwards. The Crown argued that the appellant had said certain things that had led to the disclosure, but nevertheless, Kathy Lin was still not convinced because she continued to try and call her brother. [1015]

192. [657]

     The Crown then submitted that the appellant must have said something further to Kathy Lin that had planted the idea firmly in her mind and led her to being insistent by the time she spoke with police that “[h]e is in the bed”. [1016]

193. [658]

     The Crown argued that the appellant was the source of the information about Min Lin that Kathy Lin conveyed to the police. He used her as the conduit for information he had from being the killer because he did not want to draw any attention to himself. [1017]

194. [659]

     Kathy Lin denied being the source of the information provided to police which led to the discovery of the body of Min Lin. Her evidence was to the effect that the police had found out and announced the news to the family. The Crown submitted the jury would find the evidence of Kathy Lin on this subject to be “not a reliable account”. [1018]

195. [660]

     The Crown made submissions as to why the jury would prefer the evidence of the police over that of Kathy Lin. One was that DSC Wilson became quite emotional when giving evidence about how he told the family that a fifth member of the family had also been murdered. The Crown invited the jury to regard such emotion as a sign of genuine recall of a real event. The jury was also reminded of a question that Kathy Lin was asked in her interview on 20 July 2009 by Detective Nuttall, the officer working with DSC Wilson. She asked, “[y]ou said to me at the hospital it looked like a lump” and Kathy Lin replied, “[y]es, yes, it looked like lump”. [1019]

196. [661]

     The Crown concluded its submission as follows: [1020]

197. [662]

     The appellant argued that this limb of alleged consciousness of guilt reasoning involved “a particularly strained interpretation of the evidence” and that it “also has underlying problems of lack of logic”. [1021]

198. [663]

     The appellant described the Crown’s argument regarding the discovery of Min Lin’s body as having three aspects.

199. [664]

     The first component concerned the appellant’s knowledge as the killer that Min Lin was on the bed, under the bedclothes. An argument was laid out in the written submissions for an inference to be drawn that “Kathy Lin always suspected her brother was deceased under the quilt”. There was also an argument as to the flaw in the Crown theory, unfortunately tinged with the emotive language of a jury submission: [1022]

200. [665]

     Submissions of this type appear designed to fill a void in the evidence by attributing thoughts, motives and emotions to witnesses that were not expressly or implicitly reflected in the evidence they gave.

201. [666]

     The appellant’s complaint in relation to this first component is that “the summing up failed to strike the requisite balance between the parties by referring to the relevant evidence supporting the fact that both the [appellant] and Kathy Lin suspected Min Lin was under the bedding from the outset”. [1023]

202. [667]

     The submissions, however, returned to a critique of the Crown’s argument.

203. [668]

     The appellant submitted that, assuming he was guilty, the reasoning must be that for some reason at 12.30pm, but not earlier, he wanted police to find the body of Min Lin. He also submitted that no reason why he would have this wish was ever articulated. [1024]

204. [669]

     There was no explanation provided in the submissions as to how this was relevant to the summing up.

205. [670]

     This third aspect relates to something said by the appellant in his 16 March 2010 police interview. The appellant said, “I saw Min and Lily this side”, thereby inadvertently disclosing that he had seen five bodies on 18 July 2009. [1025]

206. [671]

     At the 2016 trial, the Crown submitted to the jury that this answer was a “dreadful mistake” and that the appellant realised the mistake afterwards. This resulted in him “backtracking” by calling the officer-in-charge, DS Maree, the next morning to claim that he had in fact told an officer at the scene on the morning of 18 July 2009 that he saw five bodies. The officer in question refuted that claim. The Crown submission was: [1026]

207. [672]

     The appellant submitted in this Court that rather than being a “dreadful mistake”, his disclosures in the 2010 interview were consistent with what he said in his 2009 interview and with his conversation with Nurse Edwards on 18 July 2009. The jury was not reminded of any of that evidence and so it was necessary in the circumstances for the trial judge to do so.

208. [673]

     It was further submitted that “given the somewhat bizarre nature of this Crown theory on consciousness of guilt it was vital for her Honour to set out neutrally the relevant evidence and what the actual (logical) course of reasoning that could be taken into account was”.

209. [674]

     Nothing further was said in oral submissions about the third aspect. Indeed, the oral submissions were confined to a criticism of the Crown’s theory of the appellant using his wife as a “conduit”, but otherwise deferred to the written submissions.

210. [675]

     There is no merit in the complaint about an imbalance in the summing up in relation to these issues. Nor is there merit in the criticism of the Crown theory.

211. [676]

     The Crown theory has been summarised in detail above. There does not appear to be any problems in terms of its logic or rationality. The appellant described certain aspects as “nonsensical” but that criticism is overblown.

212. [677]

     That the Crown theory was capable of being regarded by the jury as valid can be demonstrated by some examples. One is that it was incontrovertible that Kathy Lin attempted to call her brother at 10.12am and 1.45pm. The Crown case was that this indicated she held a belief that he may possibly be alive. The Crown was not contending that she had “black and white realities of knowledge [or] lack of knowledge”. However, notwithstanding Kathy Lin may have held that belief at 1.45pm, it was only a short time afterwards that she told police that Min Lin was in the bed at the house and that she had seen the lump.

213. [678]

     Kathy Lin’s evidence on this subject was not consistent. For example, she agreed (after prevaricating) that at no time did she tell police that Min Lin’s body might be upstairs in the bedroom; yet she later said that as early as the time the appellant was driving away to take their son home she believed (and had good grounds for believing) her brother was upstairs dead in the bed: [1027]

214. [679]

     Kathy Lin’s credibility was also brought into question by her denial of the conversation with police at the hospital. She claimed that she said nothing to police until they told her that Min Lin was dead. To be weighed against that, however, was the evidence of Nurse Edwards, DSC Wilson and that police at Boundary Road had not checked under the doona in Bedroom 1 until after receiving a call from the hospital. Kathy Lin’s denial was also contradicted by an answer in her July 2009 interview in which she agreed that she had told Detective Nuttall at the hospital that she saw a lump in the bed. [1028]

215. [680]

     The appellant’s complaint about deficiencies in the summing up are groundless. Her Honour included a reasonable and fair review of the defence case on this issue. Her Honour told the jury:

216. [681]

     Her Honour also gave a firm “protective” direction, cautioning the jury about their approach to evidence of this type:

217. [682]

     There is no merit in Topic G of this sub-ground.

218. [683]

     There is no merit in the appellant’s complaints about, and of, the aspects of the trial judge’s summing up with which this ground is concerned. We are not persuaded that a miscarriage of justice occurred as a result of any of the individual aspects or of their cumulative effect. Leave to raise this ground is refused.

PART 9: Ground 6 - Alibi

1. [684]

   Ground 6 of the appeal contends that a miscarriage of justice resulted from directions given to the jury about alibi. In particular, it was contended that:

2. [685]

   Both the appellant and his wife maintained in their interviews with police in July 2009 that he was at the Beck Street home after arriving back from the family dinner on Friday, 17 July 2009. He bathed, watched television and searched the internet. He was in bed with his wife from about 2.00am until waking in the morning at about 8.00am. [1029]

3. [686]

   The Crown case was that, while the appellant may have been in bed with his wife from about 2.00am, he left at some point, committed the murders, attended to whatever was required to clean up, and was back in the family home in time for his wife and XX’s awakening.

4. [687]

   Circumstantial evidence in the Crown case that the appellant committed the murders would inferentially establish that he must have left the family home in order to do so. Another item of circumstantial evidence was the alleged sexual abuse the appellant regularly perpetrated upon Brenda Lin while she was living at the Beck Street home. As the Crown submitted to the jury, if the appellant was sexually abusing Brenda Lin at night and Kathy Lin had no knowledge of it, then she “could hardly be in a position to provide an alibi to her husband for the night of the murders”. [1030]

5. [688]

   The Crown also relied upon direct evidence in two forms. First, there was the evidence of Kathy Lin having said in out-of-court statements (and contrary to her in-court testimony) that she did not know if her husband left the bed after retiring at about 2am and before they both awoke at about 8am. [1031] Second, there was evidence of admissions alleged to have been made by the appellant in conversations with Witness A.

6. [689]

   The second form of direct evidence was an admission by the appellant to Witness A of having administered a mild sedative to his wife, having the effect that she was oblivious to his departure. Witness A’s credibility was dubious, and the Crown frankly told the jury that it only relied upon his evidence where there was some confirmation in recordings or in documents. [1032]

7. [690]

   According to Witness A (in evidence the Crown did not rely upon in itself), in an unrecorded conversation about the appellant’s case sometime in December 2011-January 2012, Witness A said, “[t]he wife is usually the weak link and the police will target the wife. Any problems with the wife?” The appellant responded, “[n]o, no problems. Mild sedation. She was asleep.” [1033]

8. [691]

   That conversation occurred before the police began using Witness A in the investigation. In a conversation recorded on 19 May 2012, Witness A sought confirmation from the appellant that he had made the admission. It included the following: [1034]

9. [692]

   The Crown submitted to the jury that the “[y]eah” was an implied assent, or confirmation, by the appellant to having previously admitted to the sedation of his wife. Otherwise, it would be expected that he would have responded to the proposition by saying something like, “What are you talking about? Sedated my wife? I never did such a thing. I never talked to you about such a thing”. [1035]

10. [693]

    There was a further conversation on 16 June 2012. It was not contemporaneously recorded but Witness A made notes soon afterwards and he was permitted to read from them when giving evidence in order to refresh his memory. In this conversation, Witness A attempted to engage the appellant about sedation, but his evidence was that the appellant could not be drawn, and he indicated by gesture at one point that he did not want to talk in the location they were at. [1036]

11. [694]

    The defence case as to alibi was simply that he was at home in bed at the relevant time. This was based upon what the appellant had said to police and upon the testimony of Kathy Lin. [1037]

12. [695]

    The defence contended that the allegations of sexual misconduct were denied so that the reliance the Crown placed upon that evidence to disprove the alibi was of no moment. [1038]

13. [696]

    The defence case was that the jury would reject any evidence given by Witness A not confirmed by a recording. The appellant contended he did not make any reference to sedating his wife in an unrecorded conversation. Uttering “[y]eah” in the recorded conversation on 19 May 2012, after Witness A had said “you told me before, your, when the murder happened, your wife sedated” was not agreeing with the proposition. There were a few utterances of “[y]eah” in the conversation and it was “just going along with the flow of the conversation”, or “just a sort of a catch-all, give away speech sound”. [1039]

14. [697]

    The defence also relied upon evidence that the family doctor’s records indicated the appellant and his wife had never been prescribed sedatives. [1040]

15. [698]

    The appellant’s written submissions described “two major complaints regarding the trial judge’s treatment of the evidence regarding alibi”: [1041]

16. [699]

    Although sub-grounds (a) and (b) appear to relate to both complaints, the complaints themselves are quite distinct and will be discussed separately. First, however, it may assist to provide the context in which the impugned passages of the summing up occurred.

17. [700]

    The trial judge commenced to deal with the topic of “alibi” at [243] of the summing up. It neatly followed from the directions as to the elements of murder as it was a negative proposition that the Crown was required to disprove beyond reasonable doubt in order to establish that deliberate acts of the appellant caused the deaths. The directions on alibi continued until [391].

18. [701]

    Her Honour dealt with the evidence of Witness A and the suggestion of sedation from [339] to [386]. The first subject of complaint concerns something her Honour said in [360]. The second subject of complaint concerns something said at [346] and [373] (and repeated at [444] to [446]).

19. [702]

    The first asserted error relates to the response by the appellant in the second line of the quoted extract from the recorded conversation on 19 May 2012 (see above at [691]). While reading a much lengthier passage from the transcript of that conversation, instead of reading “[y]eah … [indistinct]” her Honour misread it as “[y]eah, yeah”. [1042]

20. [703]

    The appellant submitted that the misreading “dramatically [changed] a vague and indistinct assent to a firm acknowledgment”. The “[y]eah … [indistinct]” was submitted to be “important in the flow of the conversation, particularly given the [appellant’s] limitations in English at the time, and the prospect that the one particular word ‘sedated’ had not been heard, not understood or misunderstood”. [1043]

21. [704]

    Pausing at this point, it is not at all clear why one “[y]eah” should be regarded as “vague and indistinct assent” while repeating the word should be regarded as “firm acknowledgment”. Senior Counsel for the appellant replayed at the hearing of the appeal the relevant part of the audio recording of the conversation and it has been available to us in chambers. We do not consider there to be anything vague or indistinct about the way the appellant uttered the word “[y]eah”. More concerning is the second part of that submission (the word “sedated” not being heard, etc) which appears to be no more than sheer speculation.

22. [705]

    It was submitted that “the whole tenor of the 1 hour 24-minute conversation on 19 May 2012 that was recorded … is inconsistent with someone admitting guilt in any way”. [1044]

23. [706]

    That type of submission could be made to a jury. It is not a submission that supports a ground of appeal asserting factual inaccuracy and a lack of balance favouring the Crown in a trial judge’s summing up. It has nothing to do with whether there was any miscarriage caused or contributed to by the trial judge misreading “[y]eah” as “[y]eah, yeah” from a part of the transcript in Exhibit FM. There could be a miscarriage if what occurred had the capacity to mislead the jury in a material respect. A submission that some evidence should have been seen in a different light is not to the point.

24. [707]

    If there could be any doubt that the trial judge’s misreading of “[y]eah … [indistinct]” as “[y]eah, yeah” in Exhibit FM was nothing other than trivial inadvertence with no material consequence, the following reasons dispel it entirely. [1045]

25. [708]

    First, the misreading occurred during a reading of a lengthy extract from the transcript of the conversation. The extract comprised 27 utterances by either Witness A or the appellant. Seven of the contributions by one speaker or the other were merely utterances of “[y]eah”, or “[y]eah, yeah”, or “[n]o”, or “[n]o, no”. In this context, it is moot whether any juror would have noticed a “[y]eah, yeah” instead of a “[y]eah … [indistinct]”, even as a response to the critical “you told me before … when the murder happened, your wife sedated” proposition.

26. [709]

    Second, when the first of the covert recordings of conversations between Witness A and the appellant was tendered, the trial judge gave the jury a direction in clear and unremarkable terms about the audio recording being the primary evidence. [1046] In summing up, the trial judge repeated this direction, both orally and in writing, eg, “it is what you hear that is the evidence in this trial”. Her Honour repeated it at some length later, immediately before reading the extract from Exhibit FM, including directing the jury to make its own judgment about what was said and with what inflexion and intonation. [1047] The trial judge could not have done more to ensure the jury was aware of the need to listen carefully to all audio recordings, including Exhibit FM, and make their own assessment of what was actually said.

27. [710]

    Third, nothing more could have been done to ensure that the jury was familiar with this recording. It was played in its entirety during the evidence‑in‑chief of Witness A. Relevant parts were played during the re-examination of Witness A as well as in each of the Crown and defence closing addresses. [1048] It was, of course, available in the jury room to be listened to as much as jurors desired.

28. [711]

    Finally, immediately after the reading of the extract from Exhibit FM with the inadvertent, “[y]eah, yeah”, her Honour reminded the jury of some cross-examination of Witness A in which he was challenged about that exchange with the appellant. The correct, single “[y]eah” response by the appellant was mentioned five times: [1049]

29. [712]

    The jury could have been in no doubt that the appellant’s response to Witness A’s proposition was a single “[y]eah” followed by something indistinct. In all these circumstances, the possibility that any juror could have been led into thinking that the response was “[y]eah, yeah” is extremely remote. Even assuming a juror was so misled, it is impossible to conceive that a juror might have thought there was any material difference. The crucial point was more whether there was an acceptable explanation for the appellant not saying something in response like, “What are you talking about?”

30. [713]

    The appellant’s submissions referred to the following extract from [346] of the summing up: [1050]

31. [714]

    This was said to support Witness A’s evidence regarding the sedation conversation and was not a submission that had been advanced by the Crown. It was repeated by her Honour in the summing up at [373] and at [444] to [446]. [1051] Moreover, it was submitted to be inconsistent with the evidence because the appellant had previously conveyed to Witness A that he was asleep at the time the murders were alleged to have been committed and that he had a wife. [1052]

32. [715]

    It can be accepted that Witness A had prior knowledge that the appellant had a wife. It would otherwise be unlikely that he would have commenced the first conversation in which sedation was mentioned (the first “sedation” conversation) inquiring whether she might be a problem.

33. [716]

    However, whether the appellant had previously told Witness A that he was asleep at the time the murders were alleged to have been committed is not entirely clear. The only source the appellant relied upon for this assertion was the following passage in the cross-examination of Witness A: [1053]

34. [717]

    This may be in conflict with some earlier evidence in which Witness A said he was “pretty sure” but “not a hundred percent” that the appellant had not told him that “he was asleep with his wife that night in the sense that he wasn’t at the place where the murders happened”. [1054]

35. [718]

    Witness A’s reference to “the time when I brought it up the first time” is temporally unclear. It might be a reference to the first “sedation” conversation because that reference was preceded by Witness A asking, obviously in the context of talking about the appellant’s case, “[a]ny problems with your wife?” It may be that in Witness A’s mind, this was him first asking the appellant about his opportunity to commit the murders. It might also be that Witness A had in mind some subsequent conversation. It appears unlikely to have been an earlier one because the general tenor of his descriptions of those conversations [1055] suggest it was unlikely that such detail would have been raised.

36. [719]

    Whatever the above analysis may indicate, the more significant issue appears to be, as the Crown has contended, that the impugned passages of the summing up concerned Witness A’s knowledge of the police investigation.

37. [720]

    There was no suggestion that Witness A would have had any information about the police investigation prior to his first contact with them. According to him, the first “sedation” conversation was prior to that first contact. The chronology of relevant events was as follows: [1056]

38. [721]

    The Crown contends that in the impugned passages of the summing up, her Honour was mindful of evidence about whether police provided Witness A with relevant information about their investigation. [1057]

39. [722]

    As noted above, [1058] Detective Sergeant Maree was the officer-in-charge of the case. The Crown adduced evidence through him that Witness A was only provided with very limited information by police: [1059]

40. [723]

    Counsel for the appellant picked up on this topic in cross-examination of DS Maree: [1060]

41. [724]

    The fact that her Honour was addressing this subject, first raised by the Crown and further developed by the appellant, is apparent from reading beyond the portion of [346] of the summing up quoted by the appellant:

42. [725]

    The first of the asserted repetitions of the misstatement is clearly in the same vein:

43. [726]

    The second passage was after her Honour had concluded what she had planned to say about alibi. Her Honour had moved to another topic and then took the luncheon adjournment. The appellant’s counsel took the opportunity to raise a concern about what her Honour had said earlier in what the transcript subsequently identified as [346] or [373] or both. Her Honour indicated that she had in mind a proposition that had been put in cross‑examination of the officer‑in‑charge of the case but rejected (thereby confirming the above analysis).

44. [727]

    Counsel’s concern was not that her Honour had said anything wrong. He was concerned with the implication that Witness A had no knowledge at all about the case before the alleged first “sedation” conversation, whereas he had in fact spoken to the appellant about the case. He referred to evidence that “prior to his going to the police, [Witness A] had … been talking to the accused about his case and the fact that it had been in a news report”. [1061]

45. [728]

    Her Honour appeared to acknowledge the fact, although she pointed out that there was no evidence of the appellant and Witness A having spoken about “the time of death … or that the accused had raised with Witness A his defence of alibi”. Counsel reiterated his point that “there had, prior to Witness A’s going to the police, been discussion about the case”, although he accepted that “it is not certain what was discussed on that evidence”. [1062]

46. [729]

    Her Honour outlined what she would say to the jury and it incorporated reference to some evidence counsel had referred to in his submissions. Counsel appeared to be content with what was proposed. [1063] It resulted in her Honour saying the following soon after the resumption; this being the second of the asserted repetitions referred to in this Court by the appellant (with our emphasis):

47. [730]

    It was the case that there was no evidence that Witness A had been provided with any relevant information about the case by police at the time of the first “sedation” conversation. There was evidence that Witness A and the appellant had discussed the appellant’s case prior to Witness A asking his solicitor to contact the police and offer his assistance. Part of that was what the trial judge reminded the jury about and there was more adduced in Witness A’s evidence‑in‑chief. [1064]

48. [731]

    Properly understood, there is nothing about this aspect that caused or contributed to a miscarriage of justice.

49. [732]

    The written submissions for the appellant referred to some discrete aspects of the summing up. It may be that the appellant was inviting the Court to find error and to consider these matters in their cumulative effect in causing a miscarriage in the manner contended for in relation to this ground. We proceed with that assumption, although the point was by no means clear.

50. [733]

    The appellant contended that, as compared to the “support for Witness A’s evidence, Kathy Lin’s evidence was subject to significant scrutiny”. This submission was not developed and all that was said at the appeal hearing was that a review of the whole of the summing up demonstrated “very, very significant criticism of Kathy Lin’s credibility”. Paragraph 377 was said to be an example. No other examples were provided. [1065]

51. [734]

    In [377] of the summing up, her Honour told the jury:

52. [735]

    What was said in this paragraph was a summary of a Crown submission. It was not said to be, or is self-evidently, wrong, inadequate or excessive. As to balance between discussion of Kathy Lin’s credibility and that of Witness A, the trial judge gave a quite detailed warning about the potential unreliability of Witness A’s evidence at the conclusion of it and her Honour gave a further, and very extensive, warning during a relatively early stage of the summing up, supplemented by a two-page written summary. Her Honour made further references to the question of Witness A’s reliability thereafter. At one point her Honour reminded the jury of defence counsel’s submission that Witness A was “a manipulator, a liar, seasoned criminal, interested only in the benefits and rewards he saw for himself and that [the jury] would place no reliance on anything that Witness A said”. [1066]

53. [736]

    It may be said as briefly as the submission was made; there is no merit in it.

54. [737]

    The appellant submitted that to the extent that the trial judge referred to arguments that had been advanced by defence counsel, they were arguments that were “patently ridiculous and had been appropriately criticised either when advanced or otherwise in the summing up: for example at SU [364]”. [1067] The point was not further developed in writing or orally.

55. [738]

    The defence arguments referred to [364] of the summing up in which her Honour told the jury:

56. [739]

    There were two defence arguments mentioned in this passage; one was perfectly legitimate and the other may have suffered from a logical fallacy in that a premise assumed the truth of the conclusion.

57. [740]

    As the Crown submissions indicated, [1068] the trial judge reminded the jury of many defence arguments and, as might be expected, some were more cogent than others. The defence characterisation of the reliability of Witness A quoted above is not self-evidently without merit.

58. [741]

    “Patently ridiculous” is a severe criticism. The assertion that it applied to all (or even many) defence arguments referred to by the trial judge cannot be made good by citing a single example.

59. [742]

    There was implied a criticism of the trial judge for making no reference to the evidence that the appellant and his wife had never been prescribed sedatives. [1069] We say “implied” because this was stated in a single sentence without any more being written or said about it.

60. [743]

    The brevity of the submission was in keeping with the extremely minor significance of the issue at the trial. There were two questions in cross‑examination of DS Maree, the officer-in-charge, in which he confirmed there was no record of the family doctor having prescribed sedatives. [1070] The appellant’s counsel reminded the jury of this three times, each time in a single sentence, in the course of a closing address that went for a great many days. [1071] More significantly, the evidence was far from definitive on the question of whether the appellant had in fact administered a mild sedative to his wife on the morning of 18 July 2009.

61. [744]

    There was also implied criticism of the trial judge for reminding the jury that the appellant’s police interviews were not sworn and not tested, with the weight to be given to them a matter for the jury, but without reminding the jury what the appellant had said in those interviews about his movements on the night of 17 and morning of 18 July 2009. [1072]

62. [745]

    We note that the “not sworn” and “not tested” characterisation was presumably based upon Mule v The Queen [2005] HCA 49; (2005) 79 ALJR 1573. It is not contended that her Honour erred in this respect.

63. [746]

    The answer to the criticism of failing to refer to the content of the interviews lies in what the trial judge in fact told the jury. This came at the end of a day, after the trial judge had provided the legal directions on the issue of alibi, and was foreshadowing the evidence on the subject she would review the next morning: [1073]

64. [747]

    Counsel in this Court did not identify any passage of the appellant’s police interviews about which the jury should have been reminded.

65. [748]

    The appellant’s written submissions conclude with the assertion that r 4 of the Criminal Appeal Rules was overcome on the basis that the asserted errors and unbalance in the summing up on the topic of alibi were so serious and significant as to have caused a miscarriage of justice.

66. [749]

    We are not satisfied that any of the individual or sundry complaints raised under this ground, even when considered for their cumulative effect, give rise to a miscarriage of justice.

67. [750]

    Leave pursuant to r 4 is refused.

PART 10: Ground 7 – Coincidence Evidence

1. [751]

   Ground 7 of the appeal contends that the trial judge erred in admitting coincidence evidence in relation to a folded, blood-soaked piece of cloth found at the Boundary Road crime scene and a “massage device” located at the appellant’s home.

2. [752]

   The Crown case was that the murder weapon had not been recovered; its theory being that it was disposed of by the appellant on the morning of 18 July 2009 after the murders. It theorised that the weapon was an improvised homemade device.

3. [753]

   A homemade “massage device” which had been constructed by the appellant was found by police at his home in 2010.

4. [754]

   The Crown alleged that certain features of the homemade massage device and what it theorised were features of the improvised murder weapon – particularly the attachment of a piece of cloth to each of them – were so markedly similar that coincidence was an improbability.

5. [755]

   The appellant accepted that the evidence of the massage device was adduced to prove that he “did a particular act”, namely attached the piece of cloth to the hypothesised murder weapon. He accepted that if this was established, it tended to prove that he was the murderer. [1074]

6. [756]

   Before reviewing the relevant evidence, it is useful to reiterate that according to the forensic pathologist, Dr Irvine, the cause of death in each case was blunt force injuries to the head, in addition to (except in the case of Irene Lin) asphyxia. [1075] It should also be remembered that it was the Crown case that the perpetrator first killed Min and Lily Lin in Bedroom 1, then Irene Lin in Bedroom 2, before killing the two children in Bedroom 3. Supporting this theory was the discovery of DNA consistent with that of Min and Lily Lin on bloodied items found in Bedrooms 2 and 3.

7. [757]

   The Crown contended that the murder weapon must have been an improvised homemade device involving a hammer or hammer-like object, rope, cloth and a red rubber band. The cloth, soaked with blood and bearing DNA consistent with that of Min and Lily Lin, was found on the floor in Bedroom 3. Also found in that bedroom was a piece of black rubber that the Crown theorised might have been wrapped around the handle of the murder weapon. It had blood on it with DNA also consistent with Min and Lily Lin’s DNA. [1076]

8. [758]

   Dr Irvine gave evidence of seeing in the head injuries of the victims “a very distinctive pattern that is very typical and familiar to forensic pathologists and that pattern is from the head of a hammer-like instrument”. She believed that the injuries she observed “are good enough to be shown in a textbook as an example of a pattern [of] injury from a hammer-like instrument”. [1077]

9. [759]

   The Crown adduced important evidence about the crime scene from two crime scene officers: Dr Raymond, who was also an expert in relation to shoe, rope and other marks, and DS Harkins, who was also an expert in bloodstain pattern analysis. [1078] They gave evidence on a number of topics, including about blood stains found at the scene that had been made by rope. (Many of these were linear stains on the walls and bedding in Bedroom 2 and Bedroom 3.) Dr Raymond said that the marks indicated that the rope was approximately 4mm in width and had been looped or coiled on itself and tied in a knot. [1079] Testing was carried out in a room set up to replicate Bedroom 2. Detective Sergeant Harkins said he was unable to replicate the marks found in Bedroom 2 with a free hanging rope, only with one that was attached to an assumed weapon (a hammer). He expressed the opinion that “the weapon itself is, by my experience, incredibly unique”. [1080]

10. [760]

    Detective Sergeant Harkins considered that the lack of any rope marks in Bedroom 1 (aside from at a light switch and the entry door) indicated that the rope was at that time secured, whether wrapped around the handle of the weapon, around the wrist of the assailant or otherwise, and came loose after the assaults on Min and Lily Lin. He opined that it came in contact with the blood of both Min and Lily Lin during those assaults, explaining their DNA being within blood stains caused by the rope elsewhere. The rope marks on the light switch and door would have been made as the assailant exited the room with the rope and the implement. [1081]

11. [761]

    A fibre expert determined that the blood-soaked cloth bound by a red rubber band found in Bedroom 3 was a mixture of colourless cotton and cellulose-based man-made fibres, most likely rayon. Possible sources of such fabric included underwear, clothing, bed sheets, blankets and other furnishings. The cloth when unfurled after removal of the rubber band measured approximately 12 x 8 cm. It was found to have DNA consistent with the profiles of Min and Lily Lin. [1082]

12. [762]

    The fabric had been folded twice. Circular depressions were evident in each quadrant, variously concave and convex, measuring approximately 1.5cm x 2cm. These depressions were suggestive of the cloth having been tightly secured over something hard. [1083]

13. [763]

    It was the Crown case that the folding of the cloth and its circular depressions suggested it had been wrapped and secured with a red rubber band over a round solid object, namely part of the head of a hammer or hammer-like implement. The Crown also suggested that the purpose of the cloth may have been to “perhaps cushion the impact of the weapon, or for some other reason, perhaps absorb the amount of blood spatter”. [1084]

14. [764]

    Dr Raymond tried to test the theory that the cloth had been wrapped around a hammer. In tests conducted in 2012 it was difficult to keep the cloth secured to the hammer but on that occasion, she was striking a pool of liquid blood. In 2016, the cloth was secured to the hammer and soaked in bovine blood. A target of foam blocks with rubber on top was then struck. On this occasion the cloth stayed in place for up to 50 strikes, except if it became caught in cracks that started to emerge in the target material. [1085]

15. [765]

    Dr Raymond was unable to obtain fabric that was identical to that which was found at the crime scene; it was only possible to obtain fabric that was all cotton or all rayon. [1086] The result was that the Crown was unable to say precisely how the blood-soaked cloth had been used. [1087] It submitted to the jury: [1088]

16. [766]

    Nothing of significance for this ground turns on the finding of the piece of black rubber in Bedroom 3 except that it supported the Crown’s description of the murderer having used an improvised home-made device. The piece of rubber was bloodstained and had DNA consistent with that of Min and Lily Lin. An expert was of the opinion it had not come from a tool commonly found in a home such as a hammer. One side had been cut with a Stanley knife and two sides had been torn. The size was consistent with it having been wrapped around the handle of a hammer. [1089]

17. [767]

    There was controversial evidence of conversations between the appellant and Witness A that were capable of being interpreted as admissions by the appellant that he used a hammer as the murder weapon which he disposed of later that morning en route to collect the grandparents. (The defence case was that the conversations with Witness A had an exculpatory interpretation.)

18. [768]

    While executing a search warrant at the appellant’s home, police found a homemade item, described as a massage device, in his bedroom. Kathy Lin identified it as a “massager” that her husband had made for his back pain. [1090] There was no dispute that he constructed it. [1091] It was described in the Crown’s submissions as follows: [1092]

19. [769]

    The trial judge admitted the evidence of the massage device as coincidence evidence in the 2015 trial (R v Xie (No 12) [2015] NSWSC 2124). A further objection to admissibility was raised in the 2016 trial but the ruling remained. Despite the trial judge indicating that a judgment would be published, that has not occurred. [1093]

20. [770]

    The ultimate submission made to the jury by the Crown was: [1094]

21. [771]

    The defence case was summarised by the trial judge: [1095]

22. [772]

    The Crown’s suggestion to the jury that the cloth became detached from the murder weapon during the attack upon Min and Lily Lin in Bedroom 1, but was dropped by the perpetrator during the violent struggle in Bedroom 3, would appear to have been made by the Crown in anticipation of the defence raising the latter points which her Honour summarised in the above extract.

23. [773]

    The trial judge reviewed the evidence relating to this issue and summarised the competing submissions that were made, neither of which attracted any criticism by the appellant in this Court. Her Honour concluded on the subject with the following directions: [1096]

24. [774]

    The provisions of ss 98 and 101 of the Evidence Act governed the admissibility of the evidence of the massage device as coincidence evidence. [1097] Section 98, in the form it took at the time of the trial, was as follows:

25. [775]

    In 2016, s 101(2) provided:

26. [776]

    It is convenient to note some matters derived from the case law on the subject (without any attempt at being exhaustive). None of this was contentious between the parties.

27. [777]

    It was held in The Queen v Dennis Bauer (a pseudonym) (2018) 266 CLR 56; [2018] HCA 40 at [61] that it is a matter for an appellate court itself to determine whether tendency evidence (Evidence Act, s 97) is of significant probative value, as opposed to deciding whether it was open to the trial judge to conclude that it was. It was the joint position of the parties that there is no reason to doubt that the same applies to the question of the significant probative value of coincidence evidence. As the concept is identical for both forms of evidence, we see no reason to doubt the correctness of this proposition.

28. [778]

    The assessment of probative value in the determination of admissibility must be made on the assumption that the jury will accept the evidence, without considering matters of credibility and reliability (IMM at [49]-[52]). In the present case, no questions of credibility or reliability arise in any event as the evidence is concerned with inanimate objects and the inferences that might arise in relation to them.

29. [779]

    The term “significant probative value” as used in ss 97 and 98 has been held to mean a probative value which is “important” or “of consequence”. The assessment of this depends upon the nature of the facts in issue to which the evidence is relevant and the significance or importance the evidence may have in establishing those facts (R v Matonwal and Amood (2016) 94 NSWLR 1; [2016] NSWCCA 174 at [77]-[78] per Bathurst CJ).

30. [780]

    Simpson J (as her Honour then was), with the concurrence of McClellan CJ at CL and Fullerton J, said in R v Gale; R v Duckworth [2012] NSWCCA 174; (2012) 217 A Crim R 487 at [30] that the factual underpinnings of a decision to admit or reject coincidence evidence are that there is evidence capable of establishing the occurrence of two or more events and there is evidence capable of establishing similarities in those events, the circumstances in which they occurred, or both the events and the circumstances in which they occurred. Her Honour continued:

31. [781]

    The existence of dissimilarities is not critical to a determination of probative value under s 98. This Court said in Selby v R [2017] NSWCCA 40:

32. [782]

    As to the balancing exercise in s 101, the High Court said in The Queen v Dennis Bauer (a pseudonym) at [73] that the expression “prejudicial effect” in s 101 [1098] conveys the idea of “harm to the interests of the accused by reason of a risk that the jury will use the evidence improperly in some unfair way”.

33. [783]

    Extensive submissions in writing were provided by the appellant, parts of which were emphasised and further developed at the hearing of the appeal. A contention was maintained that the trial judge erred in admitting the evidence relating to the massage device pursuant to both ss 98 and 101, but it was made clear at the outset of the oral submissions that the principle contention was the issue raised by s 98, whether the evidence had significant probative value. [1099]

34. [784]

    Four points were raised in support of the argument that the evidence lacked the capacity to have significant probative value:

    1. (1)

       Contrary to many cases involving coincidence evidence, here there were only two events. [1100]

    2. (2)

       The details pertaining to one of those two events (the murder weapon) were obscure. [1101]

    3. (3)

       The similarities between the two events relied upon by the Crown were relatively few, none were especially peculiar, and all were reasonably generic. [1102]

    4. (4)

       The two items had different purposes – one was murderous and the other was remedial. [1103]

35. [785]

    The first point is a statement of what is readily apparent and was not further developed. It is a matter that does not assist the appellant. Section 98 is specifically concerned with “2 or more events”. The significance of the number of events really depends upon a variety of circumstances such as the nature of the events, the uniqueness or otherwise of their qualities, and the nature of the facts in issue to which the evidence is said to be relevant. For example, if an event or circumstance is quite unique, seeing it replicated elsewhere just the once might be quite significant, whereas something less unique might need to be seen elsewhere a number of times before it could assume significance. The type of event in question in this case is quite unusual.

36. [786]

    This is the most significant of the appellant’s arguments in support of this ground. It was based upon the fact that the Crown was forced to rely on inferential reasoning to establish that the murder weapon was as earlier described: an improvised hammer-like object with the blood-soaked cloth at one time attached to it. [1104]

37. [787]

    It was accepted that there was a reasonable inference that the cloth found in Bedroom 3 had been folded over, or under, something hard and secured with a rubber band. However it was contended that there was no inference available that it had been affixed to a murder weapon. The possibility of it having been used as a gag had been raised in the 2015 trial but was not pursued in the 2016 trial (R v Xie (No 12) at [37]). [1105] The main point raised in closing address in the latter trial was that there was insufficient evidence to conclude that it had been affixed to the weapon. [1106]

38. [788]

    A problem with this is that it is difficult to formulate an alternative use to which the cloth may have been put when regard is had to all the circumstances. The inference that it had been attached under pressure to some hard, rounded object was strong. The head of a hammer, maybe a ball pein hammer, can meet that description. Fatal injuries consistent with having been caused by a hammer or hammer-like object was a powerful circumstance. The fact that the cloth was associated with the killing of Min and Lily Lin was virtually inescapable.

39. [789]

    Some specific points were identified by the appellant as potentially negating the Crown’s contention, but they were each subject to competing explanations.

40. [790]

    One point was that there was no evidence to enable an inference to be drawn from the skull fractures seen on autopsy as to the likely size of whatever was used to cause them. Although the pathologist, Dr Irvine, gave evidence of the injuries being of “a very distinctive pattern that is very typical and familiar to forensic pathologists and that pattern is from the head of a hammer-like instrument”, there was no evidence that the item was of a particular size. [1107] This was a neutral matter; it neither confirmed nor denied the Crown theory.

41. [791]

    The appellant referred to evidence that arose in cross-examination of the officer who photographed the blood-soaked cloth that she did not see any bone, hair or flesh. The officer described her task as: “I think I just took a quick look, took a photograph and bagged it up for the biologists”. An affirmative answer might have strengthened the Crown case, but her negative answer did not do otherwise. [1108]

42. [792]

    The appellant referred to evidence that Dr Irvine observed grey marks, that appeared to the naked eye to be metallic, on damaged bone in the skulls of Min and Lily Lin. She said that this might have been something that had been transferred from the weapon that caused the injury. [1109] It gave rise to the submission that “if there was some form of metallic type transfer to the skull it would suggest the blood-soaked cloth may not have been over the top of the part of the weapon that struck the skulls of those persons”. However, there were multiple skull fractures inflicted upon these two victims and this particular characteristic was not identified on each. The main difficulty with this contention is that it remains possible that the attack upon Min and Lily Lin commenced while cloth was affixed to the murder weapon and continued after it became dislodged.

43. [793]

    In relation to each of these matters raised by the appellant it is important to bear in mind that the task of determining admissibility does not involve a determination of the actual probative value of the evidence. It is, as Simpson JA pointed out in R v Gale; R v Duckworth (at [30]), a matter of identifying what the evidence is “capable” of establishing.

44. [794]

    The third issue raised by the appellant was that the similarities (conveniently listed in the Crown written submissions [1110] ) were few, not especially peculiar and all reasonably generic. They were not of such a quality to render it improbable that they could be explained by coincidence. They were:

45. [795]

    These matters were available for the jury to consider in its assessment of the strength of the inference for which the Crown contended. We consider there was enough in these similarities to support a finding of significant probative value. A key part of this is the nature of the murder weapon postulated by the Crown. We are satisfied that it was open to the jury to find that most, if not all, of its features were as the Crown contended. The rope attachment is an example of something that was particularly compelling in light of the blood spatter evidence left at the scene. Detective Sergeant Harkins’ description of the weapon having such features as “unique” in his considerable experience was evidence that could well have carried considerable weight with the jury.

46. [796]

    Acceptance of the murder weapon as being as described by the Crown – a unique improvised, homemade device – could then be assessed alongside the undisputed evidence of the appellant having constructed the rather unique, improvised, homemade massage device. Construction of both items required relatively rudimentary skills and equipment, both of which the appellant possessed. Added to this could be the prospect that both items had the feature of folded cloth secured by rubber bands around a metal component. This evidence, in the context of all of the other evidence adduced by the Crown, was well capable of assisting the jury to a conclusion that the appellant constructed the murder weapon. It inexorably follows that the evidence was capable of being regarded by the jury as having significant probative value.

47. [797]

    The final issue raised by the appellant at the hearing of the appeal was the different uses of the implements (one murderous and the other remedial). This was not further developed and that is unsurprising. The motive for similar actions does not deny the similarity of the action. There is no merit in this point.

48. [798]

    In the written submissions, the appellant noted a number of other dissimilarities: different types of fabric; different sizes; different number of folds; one secured to a metal bolt and the other not; and that the murder weapon was not suggested to be a “wooden contraption” like the massage device. Further, the red rubber bands were of a common type and not amenable to any meaningful comparison. Finally, “the piece of blood-soaked cloth was not found in the state relied upon to ground the asserted similarities – this was a matter of inference”. (We take this to mean that it was not secured to a murder weapon as the Crown alleged.) [1111]

49. [799]

    Many of these points do not deny the availability of coincidence evidence reasoning. None of them foreclose a mode of reasoning based on similarity (see Selby v R above at [781]).

50. [800]

    As to s 101(2), it was accepted in the written submissions that no objection on this basis was taken at trial and so leave pursuant to r 4 of the Criminal Appeal Rules was required. [1112] It is notable that not only was no point taken by the two counsel who appeared for the appellant at his trial in 2016, no point was taken by different counsel (senior and junior) who appeared at his 2015 trial.

51. [801]

    The appellant criticised the trial judge for being satisfied that the test should be resolved in favour of admitting the evidence because counsel for the appellant did not submit otherwise. It was submitted that this was erroneous because the absence of a submission did not relieve her Honour of the burden of reaching satisfaction that the probative value of the evidence substantially outweighed any possible prejudicial effect. [1113]

52. [802]

    This relates to the original decision as to admissibility made over the objection of Senior Counsel then appearing for the appellant in the 2015 trial. In her judgment, the trial judge referred to the fact that counsel had not made any submission on a certain topic relevant to the s 98 issue and then continued (R v Xie (No 12) at [54]):

53. [803]

    Her Honour did not say, as the appellant asserts, that it was because counsel did not assert to the contrary the test should be resolved in favour of admitting the evidence. It was more a matter of her Honour noting the implicit concession that there was no danger of unfair prejudice that would require exclusion if, pursuant to s 98, the evidence was found to have significant probative value.

54. [804]

    In this Court, for the first time, the appellant contended that there was a danger of unfair prejudice in that there was a risk the jury would give the evidence disproportionate weight. That was because jurors would be unable to evaluate: [1114]

55. [805]

    It was submitted that, because there was no evidence to enable the jury to determine whether it was improbable or not that the asserted similarities occurred coincidentally, the jury was required to engage in speculation. This carried the risk that the jury would give the evidence undue weight. Whatever probative value the evidence had; it was submitted that it did not outweigh this possible source of prejudice. [1115]

56. [806]

    These submissions do not pay sufficient deference to the intelligence and commonsense of jurors. All these matters are readily assessible in accordance with the common and everyday experience of life. There was no justification for excluding the evidence pursuant to s 101(2).

57. [807]

    The coincidence evidence was correctly held to be admissible.

58. [808]

    We would grant leave under s 5(1) of the Criminal Appeal Act to raise this ground of appeal but reject the ground.

PART 11: Balance of Ground 8 – Conduct of Counsel

1. [809]

   As already noted, Ground 8 contends that a miscarriage of justice was occasioned by a number of acts and omissions of the appellant’s counsel at trial. The principles applicable to this ground are set out above. [1116]

2. [810]

   The appellant relied upon 12 particulars in relation to Ground 8. It was submitted they individually or cumulatively caused a miscarriage of justice. [1117]

3. [811]

   Particulars (i) to (vi) relating to the DNA material in Stain 91 and the evidence of Dr Perlin have been discussed earlier. [1118]

4. [812]

   Particulars (vii) to (x) raise various issues concerning the evidence of Witness A and particulars (xi) and (xii) complain of a failure by trial counsel to seek correction of the summing up in relation to the issues with which Grounds 5 and 6 are concerned.

5. [813]

   The essence of particular (vii) was described as a complaint of “the failure of counsel to understand or engage with” the evidence concerning Witness A and “Plan A” and “Plan B”. [1119]

6. [814]

   Witness A described Plan A as “the accused would be released from custody, either on bail, or by being acquitted at committal”. It failed as a plan when the appellant was committed for trial on 19 December 2012 and was refused bail on 24 December 2012. [1120] However, it also included using a corrupt police officer to provide information that would assist in achieving either of those ends. [1121]

7. [815]

   Plan B was described by Witness A as “quite broad reaching … it all included Harry. Anything that Harry would do, whether it be approaching a corrupt official, or anything shady, was all [P]lan B”. [1122] (“Harry” was Witness A’s contact outside gaol who was supposed to implement Plan B. [1123] In fact, he was an undercover police officer.)

8. [816]

   Plans A and B were not separate and distinct. The discussions between Witness A and the appellant about using Harry had commenced as early as 2 June 2012 when the appellant said of his prospects of getting bail, “if he can give me good information … more chance”. [1124]

9. [817]

   The appellant referred to the matters below as instances of counsel failing to understand or engage with the evidence concerning these “plans”.

10. [818]

    Contrary to the above, the appellant characterised the Crown case in relation to Plan A as involving no irregularity [1125] but despite this, the appellant’s counsel had put to Witness A “that surely there must have been something wicked that the [appellant] was up to in Plan A”. (A question in those terms was disallowed and it was replaced with, “Wasn’t there something bad that he was trying to do in [P]lan A?”) The preceding question contained the opposite characterisation of Plan A: “So was [P]lan A simply [the accused’s] plan to face his committal, deal with it as best he could, and otherwise hope for the best thereafter?” The impugned question appears to have been exploratory as opposed to putting an aspect of a case to the witness. Nothing came of it. Counsel did not pursue it after Witness A responded, “I don’t know sir”. [1126] Accordingly, this exchange was quite insignificant.

11. [819]

    Another criticism was that the apparent misunderstanding by defence counsel of details of the Crown case in relation to Plan B resulted in many opportunities for Witness A to “display authority”. [1127] Despite the assertion of “many opportunities”, the appellant provided only one instance. It was in cross‑examination when counsel attempted to describe an aspect of one of the plans discussed between the appellant and Witness A when Witness A disagreed with the description. During this exchange over a series of questions and answers, Witness A said, “[n]o you’re off track there. I’m happy to clarify it for you though”. [1128]

12. [820]

    The cross‑examination of Witness A commenced around the middle of one day and concluded sometime in the afternoon of the next. It occupies in the order of 120 pages of transcript. [1129] The single answer by Witness A quoted above was in relatively mild terms and cannot reasonably indicate what the appellant suggests. It did not cause or contribute to any miscarriage of justice.

13. [821]

    In any event, the error imputed to defence counsel in the question that prompted Witness A’s retort was not an error at all. The appellant submitted that, when referring to one of the proposals discussed under the umbrella of “Plan B”, the impugned question involved counsel mistakenly “thinking [Lily Lin’s phone] was to be placed near a cadaver”. [1130] In earlier cross‑examination of Witness A, counsel had referred to the proposal involving “the planting or placing of a mobile telephone handset, amongst other things, in proximity to or otherwise within the space of the corpse”. He then corrected himself, saying “[w]hen I said ‘proximity’, [Witness] A, look, I was referring to the item, amongst other items, being placed somewhere which had some link to the cadaver”. [1131] Counsel did not misunderstand the evidence.

14. [822]

    The next instance of defence counsel misapprehending the Crown case as to Plan B, according to the appellant, was in a submission made to the jury. Counsel said: [1132]

15. [823]

    Counsel then referred to a visit to the gaol made by Harry, following which the appellant was recorded telling his wife that he did not want to see Harry anymore. The submission continued:

16. [824]

    The appellant drew attention to the fact that in the next break, the trial judge indicated to counsel that consciousness of guilt was not foreclosed because the appellant said he did not want to see Harry again after the meeting. Her Honour said she would be directing the jury that they could find a consciousness of guilt based upon the conversations between the appellant and Witness A that preceded the appellant receiving a visit from Harry. [1133]

17. [825]

    The appellant referred to counsel having persisted with the same point during his address the next day, in fact, the day after that, 8 December 2016. [1134] The point about this instance is that counsel refined his submission, perhaps as a result of the exchange earlier. He referred to the recorded conversation between the appellant and his wife in which he referred to Harry and not wanting to talk to him again. His submission to the jury, again, was that what the appellant said was “not the language of agreement … he never agrees with Harry”. Significantly, counsel couched his submission in terms of “the issue of agreement with Harry is not the be all and the end all” but that it was nevertheless “a relevant matter to which you may have regard”. [1135]

18. [826]

    The appellant then referred to counsel continuing in the same vein on the following day of his address, 9 December 2016, including describing “one of the really important big ticket items … whether or not [the accused] ever agrees with Harry”. [1136] This was said in the context of counsel trying to provide a benign explanation for the appellant’s association with Witness A. Counsel spoke of the appellant being in the custodial environment for the first time; it being stressful and unfamiliar; and the regime being such that it “involves a great deal of time with not much to do”. He submitted that it need not be inferred that there is something sinister in the association because “it may speak simply to the fact that human beings are essentially social creatures”. [1137] That was a broad submission and the reference to a “big ticket” issue may have been to emphasise the importance of that particular point in that broad context. It was an important point in the defence case on this subject as explained in a submission counsel made that the appellant did not refer to:

19. [827]

    Trial counsel here indicated that a finding that there was no agreement with Harry was indicative of the appellant having never intended to carry through with Plan B. None of the discussions with Witness A that preceded the appellant’s refusal to proceed with the plan, or to speak with Harry again, supported an inference of consciousness of guilt.

20. [828]

    The trial judge came to understand the point when she again queried the logic of counsel’s submission at the next break. After initially speaking critically as her Honour had previously, the trial judge said, “I am sorry, I see what you mean”. [1138] Her Honour said she now understood counsel was making the point that, if the jury was satisfied there was no agreement with Harry, “it is a matter for the jury, you say, as to whether that neutralises all the steps up to that point”. [1139]

21. [829]

    Ultimately, the defence case in relation to Plan B was encapsulated by her Honour in summing up: [1140]

22. [830]

    Other instances of counsel misunderstanding this evidence were said to be his contention that a Shepherd direction would be needed requiring proof beyond reasonable doubt that the appellant agreed to join Plan A or Plan B and a suggestion that s 137 of the Evidence Act was relevant. [1141] These were matters discussed in the absence of the jury with counsel’s suggestions being relatively quickly rejected by the trial judge. It is what was said in the presence of the jury that is pertinent to whether the conduct of counsel may have caused or contributed to a miscarriage of justice.

23. [831]

    Another criticism was counsel comparing the likelihood of the appellant agreeing with Plan B to receiving assistance from an “alien spaceship”. [1142] This was something of a rhetorical flourish but counsel’s essential point was that there were some “exceedingly odd” and “pretty unbelievable” aspects to Plan B. That was a fair point.

24. [832]

    The appellant ultimately submitted that, because of the various failings of defence counsel, “there was effectively no meaningful submission on this topic before the jury”. Having regard to the way in which the trial judge encapsulated the defence case as indicated above, we reject that submission.

25. [833]

    The written submissions for the appellant then advanced an alternative case that might have been made on his behalf. [1143] We are satisfied that the approach taken by counsel represented a rational and legitimate choice. The fact that different counsel considers another argument to be a better one is beside the point. In this regard it is of interest that Senior Counsel who appeared for the appellant at his third trial in 2015 adopted precisely the same case theory in relation to this issue as counsel at the 2016 trial. [1144]

26. [834]

    The appellant’s submissions in relation to this particular make an assertion similar to one made in relation to the previous particular; there was a “loss of authority” caused by a misunderstanding by counsel about some evidence. The Court was not referred to any principle or authority in relation to such an assertion. We take it to mean that the credibility of the appellant’s counsel was adversely affected and that this in turn negatively impacted the jury’s assessment of the defence case to the point that it caused or contributed to a miscarriage of justice.

27. [835]

    Particular (viii) is relevant to the Crown’s allegation that the appellant told Witness A that he had given “mild sedation” to his wife so he could leave the house undetected and commit the murders. The evidence has been reviewed earlier in the context of Ground 6 under “Crown case in relation to alibi”.

28. [836]

    In cross‑examining Witness A, defence counsel put that the appellant had never used the word “sedate”; it was Witness A’s word. Witness A responded: [1145]

29. [837]

    In closing address, counsel reminded the jury of the recorded conversation between the appellant and Witness A in which the word “sedate” was first used by Witness A. (The conversation has been set out earlier in relation to Ground 6.) The appellant’s submissions note that her Honour intervened to explain that Witness A was only using the word to police on the basis that he was attributing it to the accused. [1146]

30. [838]

    We note that the trial judge merely said, “[b]ut it is a word he attributes to the accused Mr [counsel]”. Counsel responded by repeating his point that it was incorrect for Witness A to claim that “[i]t is not a word I have used ever” as the recorded conversation revealed. As the Crown pointed out [1147] , it may have been a weak point to be made about Witness A’s credibility, but it did not indicate a misunderstanding of the evidence. In any event, it was such a mild incident that it cannot have had much if any impact upon counsel’s “authority”.

31. [839]

    Next the appellant referred to counsel submitting that “the issue of sedation had its genesis in prompts from the officer‑in‑charge, [DS] Maree”; the Crown Prosecutor pointing out in the jury’s absence that this was a misunderstanding of the evidence. The appellant submitted that there was then “something of a correction, although not a retraction about [DS] Maree”. [1148]

32. [840]

    The appellant’s description of “something of a correction” could more correctly be described as defence counsel providing the jury with a complete and correct summary of the evidence as to how and when the topic of sedation first arose: [1149]

33. [841]

    This removed the suggestion of the sedation topic having its genesis in prompts from DS Maree and correctly reminded the jury that the Crown case was that “sedation” had been first mentioned by the appellant but in an unrecorded and disputed conversation prior to the police involvement with Witness A. The implied criticism of defence counsel is not borne out. The Crown did not seek a retraction and none was required.

34. [842]

    The next matter raised by the appellant is that the trial judge intervened to correct the reading of transcript during subsequent submissions by counsel. [1150] The submissions reference a passage of five transcript pages [1151] but nowhere in that passage is there any intervention in relation to transcript correction. There were two interventions by her Honour in that passage; one was to ask counsel to repeat something and the other was to respond to something counsel appeared to at least partially direct to her while he was reading some transcript. (In the course of reading from transcript, counsel said, “[t]hen at 3976, subject to her Honour’s learned ruling”). The trial judge said something about whether it was necessary but told counsel to keep going. [1152]

35. [843]

    The appellant then asserted that a “submission was advanced on the basis of this misunderstanding that the police use of Witness A was ‘a story in search of an author’ and was criticised by her Honour in the Summing Up”. [1153] It appears that the “misunderstanding” related to how the topic of “sedation” arose. As indicated above, ultimately (at least) there was no misunderstanding.

36. [844]

    One theme that permeates the appellant’s case is criticism of the competence with which the defence case was conducted. It is notable in relation to this particular that counsel pursued with the jury its most significant aspects. Counsel referred to there being no explicit admission made by the appellant that he had sedated his wife, aside from the dubious evidence of Witness A of an unrecorded conversation. He referred to the Crown relying upon a mere “[y]eah” in a recorded conversation which was just something said in the flow of the conversation.

37. [845]

    The appellant’s submissions in relation to particular (ix) raise criticisms of trial counsel for putting to Witness A that several inculpatory conversations occurred. It is significant to bear in mind that these were conversations not introduced by counsel. They were conversations adduced in evidence by the Crown.

38. [846]

    Witness A said there was the following conversation on 16 June 2012. It was not recorded but he gave evidence with the assistance of a note he had made after the event. [1154]

39. [847]

    Witness A went on to say that according to his note, there was no verbal response, but the appellant “shook his head and waved his hand, indicated strongly he would not comment on this subject”. Witness A said he replied, "[n]o, no, I understand, my apologies …”.

40. [848]

    The appellant submitted that this conversation was inculpatory for the following reasons: [1155]

41. [849]

    It is difficult to see merit in these submissions when one considers that the suggested reasons for characterising the conversation on 16 June 2012 as “inculpatory” apply equally to the recorded conversation that had occurred four weeks previously, on 19 May 2012. [1156] (This is the conversation that included the appellant saying, “[y]eah” in response to Witness A saying, “you told me before, your, when the murder happened, your wife sedated”.)

42. [850]

    Faced with the 19 May 2012 conversation being in evidence in recorded form, and Witness A having given evidence of the subsequent conversation based on notes he claimed to have made soon after, defence counsel had to deal with the latter conversation in some form. He chose to pursue a course of portraying Witness A as continually fishing for an admission and the appellant consistently refusing to take the bait on every occasion.

43. [851]

    Taking advantage of the lack of corroboration by way of recording and contending that the conversation on 16 June 2012 did not occur would have been fraught with the problem of it being in similar terms to the one on 19 May 2012.

44. [852]

    Another difficultly, seemingly not considered by the appellant’s counsel in this Court, is that trial counsel may have been bound by instructions. It may not have been a matter for counsel to choose whether to dispute that the 16 June 2012 conversation occurred in the terms deposed by Witness A. We have already addressed the evidence that can be adduced in relation to complaints of this nature. [1157]

45. [853]

    This leads to a further criticism by the appellant that trial counsel raised with Witness A other occasions in which he had tried to talk to the appellant about having sedated his wife but would get a response by way of the appellant getting “toey” or “touchy”. This approach included raising occasions that were not the subject of evidence adduced by the Crown. The appellant contended that this “was only damaging to the defence case”.

46. [854]

    The overall submission by the appellant was that “there is objectively no rational explanation as a matter of forensic choice for this path being embarked on. … The path undertaken as set out in this particular of this ground only acted to enhance Witness A’s credibility in this respect”. To the contrary, we are satisfied that there was an objectively rational explanation for trial counsel to have adopted the impugned approach to this aspect of the evidence of Witness A.

47. [855]

    As with particular (viii), it is of note that the impugned approach taken by trial counsel was mirrored in the approach taken by Senior Counsel who appeared for the appellant in the 2015 trial. [1158]

48. [856]

    The Crown alleged the real reason the appellant left his wife at Boundary Road on her own after the discovery of the bodies was that he wanted to dispose of the incriminating evidence he had collected from the Beck Street home when he took XX there. This proposition was partly based upon what the Crown contended was an implicit admission in a recorded conversation with Witness A on 13 October 2012, [1159] in which he expressed concern that there “may be” some CCTV footage of him disposing of the hammer on the way to pick up the grandparents. [1160]

49. [857]

    The appellant’s written submissions provided extracts from the Crown’s opening address to the jury in which reference was made to this topic. It was submitted that it was a topic that “stands out” in that address, along with the contention of there being evidence of the blood of four or five of the deceased being found on the appellant’s garage floor. [1161]

50. [858]

    The appellant noted that defence counsel made an application for the discharge of the jury because part of the Crown’s opening address on this topic was “too argumentative, without evidentiary support and ‘a bridge too far’”. We note that this application was concerned more broadly with the Crown address and that this topic was cited as one of four examples. The application was summarily rejected without the Crown being called upon. [1162] However, the appellant’s point is that nothing was subsequently said in the defence opening address as to whether the implied admission to Witness A was or was not in dispute. The appellant referred to s 159 of the Criminal Procedure Act 1986 that allows for a defence opening following the opening address of the prosecutor, provided it is “limited generally to an address on the matters disclosed in the prosecutor’s opening address, including those that are in dispute and those that are not in dispute” (as well as matters to be raised by the defence). [1163]

51. [859]

    The appellant contended that in closing address the Crown referred to this topic in “even stronger terms” (than in opening), but in the lengthy defence closing address there was nothing said about the recorded conversation with Witness A. (The Crown accepts the latter to be the case. [1164] ) Counsel did submit that the jury should not accept anything said by Witness A that was not recorded. He also submitted that, in relation to the recordings, the jury “will make of them what you make of them”. [1165]

52. [860]

    The appellant’s submission was “there was much able to be said against the construction of this conversation urged by the Crown”. There was “no objectively rational explanation for such failure as a matter of forensic choice, and the jury [was] left with a one-sided argument about potentially one of the most important pieces of evidence in the trial”. We accept that this matter was a significant circumstance in the Crown’s case, but many of the circumstances could be described as “important”.

53. [861]

    We are satisfied that defence counsel was presented with a conundrum as to how to deal with the issue of the alleged implied admission to Witness A. The trial judge also acknowledged the difficulty defence counsel faced during an exchange with him in which she expressed concern about the prospect of her reminding the jury of another recorded conversation with Witness A: [1166]

54. [862]

    On the appellant’s case now, trial counsel should have referred to the evidence and made submissions as to why the jury would not accept the Crown’s contention. If this approach was taken, it would have been necessary to remind the jury of the detail of the evidence. That would carry the risk of the jury calling to mind the quite valid argument of the Crown: [1167]

55. [863]

    It is significant that despite the assertion that “there was much able to be said against the construction of this conversation urged by the Crown”, there is no suggestion as to what counsel should have submitted.

56. [864]

    The issue of the alleged implied admission to Witness A was a component of a broader topic discussed earlier under the heading “Topic E – Leaving Kathy Lin” in relation to Ground 5(b). Other components of that topic included the content of the various triple-0 calls and the evidence of people who saw the appellant and Kathy Lin at Boundary Road. There was also the evidence of the grandfather and Kathy Lin to consider. The jury was left in no doubt that the appellant disputed there was anything incriminating about any of his conduct on 18 July 2009, including that he left Kathy Lin at Boundary Road in order to dispose of the murder weapon. As summarised in the Crown’s submissions, defence counsel developed the following points in his address to the jury: [1168]

57. [865]

    What the appellant said to Witness A on 13 October 2012 was clearly not an explicit admission and the Crown did not suggest otherwise. Defence counsel did not need to tell the jury that the Crown relied upon it to make a particular interpretation of what was said. The prosecutor submitted to the jury, “[t]he Crown says … that the accused has, in that recorded conversation implicitly admitted to Witness A …”. [1169] The trial judge made it abundantly clear in her summing up that it was necessary for them to consider counsel’s submissions in the light of their own judgment of what the evidence established. [1170]

58. [866]

    In all of the circumstances, it was appropriate for the defence case in relation to the conversation with Witness A on 13 October 2012 to be left to the jury in the fashion summarised by the trial judge to the jury: [1171]

59. [867]

    We are not satisfied that a miscarriage of justice was occasioned by this aspect of the conduct of the appellant’s counsel.

60. [868]

    It follows from our determination of Grounds 5 and 6 that there is no substance to these grounds. There was no correction needed in relation to the summing up on those issues.

61. [869]

    There is no merit in the appellant’s criticisms of defence counsel in any of “Particulars” (i) to (xii). Leave to appeal pursuant to s 6(1) of the Criminal Appeal Act in respect of this ground is refused.

PART 12: Disposition

1. [870]

   At the hearing of the appeal, Senior Counsel for the appellant submitted that, if the Court were to uphold any of the grounds of appeal, then it should receive further submissions on whether to order a retrial or enter acquittals. It follows from the rejection of all the grounds, that circumstance does not arise and the appeal must be dismissed.

2. [871]

   Accordingly, the Court orders that: