R v Xie (No 18)

1. [1]

   HER HONOUR: By notice of motion filed on 18 November 2013, the accused sought the exclusion of various categories of evidence, including what was described in the motion as “the evidence of DNA analysis” relating to Item 550 (Stain 91) the Crown proposed to call from Mr Clayton Walton, Mr Robert Goetz, Ms Sharon Neville, Dr Simon Walsh and Dr Mark Perlin, on the basis that their evidence did not satisfy the test of relevance under s 55 of the Evidence Act 1995 (NSW) or, if relevant, that it should be excluded in the exercise of discretion under ss 135 and 137 of the Evidence Act. The accused also sought the exclusion of evidence relating to the sampling of Stain 91 from the floor of the accused’s garage at Beck Street on the basis that the Crown could not establish that the stain was blood or contained blood.

2. [2]

   At the hearing of the motion in a pre-trial hearing before Johnson J convened in November 2013, and over successive hearing dates up to and including 14 April 2014, a considerable body of evidence was called concerning the “DNA analysis”.

3. [3]

   On 30 April 2014, his Honour dismissed the accused’s notice of motion and published a detailed judgment (R v Xie (No 4) [2014] NSWSC 500).

4. [4]

   At the commencement of the trial before me in February 2015, senior counsel for the accused advised that no application would be made under s 130A(3) of the Criminal Procedure Act 1986 (NSW) and, accordingly, that I should regard myself as bound by his Honour’s pre-trial rulings on the admissibility of the DNA evidence.

5. [5]

   As at the date of this judgment, the Crown has called evidence in the trial from three forensic biologists concerning the sampling of Stain 91 and the various presumptive tests for the presence of blood they applied to the stain in situ. The cumulative effect of their evidence is that the stain is “possibly blood”.

6. [6]

   Mr Walton, a forensic biologist and the DNA Manager of the laboratory within the NSW Forensic and Analytical Science Service (FASS), has given evidence of the mixed DNA profiles he generated from the stain over the course of successive testing since 2011, culminating in the use of PowerPlex 21 in 2013. It is common ground that Stain 91 was insufficient to perform a confirmatory blood test in laboratory conditions at FASS and to undertake DNA profiling. The accused does not challenge Mr Walton’s election to undertake DNA analysis of the stain. It was at that time that Stain 91 was renamed Item 550. It will be referred to as Item 550 in this judgment.

7. [7]

   Mr Walton identified at least four individual contributors of DNA to Item 550, possibly five and maybe more. In the major component he identified three related males sharing the same Y-profile as the deceased Min Lin, and probably one female. Neither of the deceased Lily Lin nor Irene Lin could be excluded as contributors. The accused and his son were excluded as the contributing males.

8. [8]

   The Crown case is that the evidence of the forensic biologists who observed the visible appearance of the stain in situ, and the strength of its reaction to presumptive testing by otolodine and fluorescence before it was sampled for DNA testing, coupled with the DNA profiles generated by Mr Walton and the evidence of Dr Perlin as to the statistical likelihood of the DNA of the deceased being represented in Item 550, entitles the jury to conclude that Item 550 contains the blood of each of the five deceased. The Crown relies upon this evidence as strongly probative of the accused’s guilt.

9. [9]

   It is not necessary to refer in detail to the evidence of Mr Walton or Dr Perlin for the purposes of resolving what has surfaced in the trial as a reformulated challenge to the admissibility of the evidence of Mr Goetz and Dr Walsh. For the purpose of determining that question, the parties accept that Dr Perlin’s statistical analysis of likelihood ratios utilising the TrueAllele program provides no statistical support for the opinions they gave as to the fact and degree of similarity in the DNA profiles Mr Walton generated from the samples he was given.

10. [10]

    The evidence of Mr Goetz and Dr Walsh that is under challenge is to the effect that there are observable similarities, to a “high degree”, between the results of Mr Walton’s analysis of the mixed DNA profiles in Item 550 on the one hand, and his analysis of the DNA profiles of the five deceased and the mixed DNA profiles in a number of blood stains, also of various of the deceased, sampled by crime scene officers at 55A Boundary Road on the other. This evidence is relied upon to support the Crown’s ultimate submission that the jury can infer that there is a mixture of the deceased’s DNA in Item 550, and that it is in blood which the accused transferred on his body or a weapon or weapons from Boundary Road where he killed the deceased to his garage in Beck Street.

11. [11]

    Mr Goetz and Dr Walsh gave evidence at the pre-trial hearing in 2013 and 2014, and in the committal proceedings in 2012, concerning the similarity in the number of alleles and their relative peak heights in each of Item 550, the DNA profiles of the deceased taken at post-mortem and in the DNA analysis of various deposits of the blood of the deceased at the crime scene. That said, it is not immediately apparent from his Honour’s summary of their evidence, or the submissions of counsel concerning it to which his Honour referred in his judgment, that in considering whether the evidence satisfied the tests for admission under s 55 and 79 of the Evidence Act, sufficient focus was given to the particular purpose to which the Crown sought to put their evidence in proof of its case at trial, or at least not with the specificity the Crown articulated in its submissions before me.

12. [12]

    Although his Honour found that both tests were satisfied, again it appears that he did not have the assistance of counsel in interrogating the precise use to which the Crown proposed to put evidence of the fact and degree of similarity between Item 550 and the crime scene samples, and the reasoning the Crown would invite the jury to adopt in inferring that the deceased’s DNA in Item 550 was in blood, accidentally or inadvertently transferred by the accused after the killing, independently of the use to which the evidence of other DNA witnesses nominated in the notice of motion would be put in proof of the accused’s guilt.

13. [13]

    In making those observations I intend no criticism of his Honour. The Crown’s approach at the pre-trial hearing to the challenge mounted by the accused to whether Item 550 could be proved to be blood, and the related challenge to the admissibility of the DNA evidence from each of the Crown’s expert witnesses who either generated DNA profiles, including of Item 550 (Mr Walton), or who commented upon the profiles that were generated (Dr Walsh and Mr Goetz) and the statistical modelling Dr Perlin provided using the TrueAllele computer program based on Mr Walton’s data, was summarised by his Honour at [236] as follows:

14. [14]

    His Honour went on to say at [238]:

15. [15]

    In the result, his Honour found:

16. [16]

    Additionally, although his Honour set out at [148]-[175] the principles that applied in determining the relevance of the evidence under s 55 of the Evidence Act, the admissibility of expert evidence and the construction and application of s 79 of the Evidence Act, including the operation of ss 135 and 137 were the evidence found to be relevant and admissible, at [430]-[442], it seems that his Honour elided the application of the discretions so that they were not considered referable exclusively to the evidence of Dr Walsh and Mr Goetz, but also to the discretionary challenges mounted by the accused to the admission of all the DNA evidence, including Dr Perlin’s evidence in its totality.

17. [17]

    It was not until Mr Turnbull objected to a question asked of Mr Goetz in the trial concerning the similarity between the number of alleles in various of the mixed contributor samples from the crime scene and Item 550, and what he considered to be the significance of that observation, that what I regard as the necessary critical focus has been given to whether that aspect of his evidence (and that of Dr Walsh who is yet to give evidence) meets the test for admission in s 55 of the Evidence Act and whether it qualifies as opinion evidence under s 79 of the Evidence Act.

18. [18]

    As the argument developed, Mr Turnbull also submitted that the Crown’s intended use of the evidence of Mr Goetz and Dr Walsh, namely that it is improbable that there were, “coincidentally”, two mixed deposits of the deceased’s DNA geographically distant from each other, also invites the jury to undertake propensity reasoning in breach of the coincidence rule in s 98 of the Evidence Act. That submission was advanced for the first time in the accused’s written submissions dated 8 July 2015.

Mr Goetz’s evidence at trial

1. [19]

   Mr Goetz has given evidence before the jury without objection that he was consulted by the ODPP in 2013 to review the DNA profiling of Item 550 undertaken by Mr Walton utilising the PowerPlex 21 system (which, at that time, was the most advanced DNA profiling test in use in NSW). Mr Goetz said that he was also invited to review the DNA profiles Mr Walton generated from Items 616, 47 and 223 using the PowerPlex 21 system, being blood samples taken from, respectively, the mattress in Bedroom 3, the internal doorknob of the handle to Bedroom 2 and a scraping from a rope transfer on the wall in Bedroom 3 (“the crime scene samples”). His observation that there were similarities in the number of alleles and in the peak heights of alleles (representing the relevant proportions of alleles at each loci) in the crime scene samples and Item 550, proceeded on the assumption that Mr Walton’s DNA profiling of Item 550 using PowerPlex 21, and his analysis of the electropherograms (EPGs) that were generated, was accurate and comprehensive. There has been no challenge to Mr Walton’s evidence concerning the various tests he applied in generating those profiles or, for that matter, his ultimate opinion as to the likely number of contributors to the mixed DNA profile generated from Item 550, in both the major and minor components of it.

2. [20]

   Mr Goetz has given evidence, also without objection, that he confirmed Mr Walton’s designation of 75 alleles in Item 550 and the same number of alleles in the combined DNA profiles of the five deceased. A large number of the 75 alleles in the combined DNA profiles of the deceased, and in Item 550, were also designated in the DNA profiles extracted from Items 223 and 47, being 70 and 75 alleles respectively. In Item 616, 61 of the 75 alleles in item 550 were present. It was the allele numbers and their relative peak heights in Item 550 and in the crime scene samples that were said by Mr Goetz to be “similar”.

3. [21]

   It is important to note that Mr Walton gave evidence about the identity of allele numbers and their peak heights earlier in the trial, also to which no objection was taken. However, he cautioned against extrapolating from the pure visual comparative exercise involved in noting allele numbers and their peak heights in the EPGs generated in the profiling of Item 550 anything as to the number or the identity of contributors of DNA to that sample. In the course of examination in chief, Mr Walton gave the following evidence:

4. [22]

   At that point, Mr Turnbull objected on the basis that the evidence the Crown was seeking to adduce from Mr Walton was misleading. I heard his evidence as to the significance, or possible significance, of the same or a similar number of alleles in the DNA extracted from Item 550 and the combined DNA extracted from the blood of the deceased on the voir dire. I was not alerted by counsel at that time to the controversy generated by Mr Goetz and Dr Walsh’s review of Mr Walton’s findings, the subject of argument before Johnson J at the pre-trial hearing.

5. [23]

   In the absence of the jury, Mr Walton was asked the following questions:

6. [24]

   When Mr Walton’s evidence resumed in the presence of the jury, the following questions were asked by the Crown:

7. [25]

   In cross-examination before the jury, Mr Turnbull asked Mr Walton the following question:

8. [26]

   Returning to Mr Goetz’s evidence at trial, Mr Goetz was asked by the Crown Prosecutor whether the 75 alleles designated by Mr Walton in Item 550 “could have come” from the five deceased, to which he answered “yes”. (Properly understood, however, that answer means nothing beyond the fact that the deceased could not be excluded as contributors to Item 550.) The following questions were then asked:

9. [27]

   The jury were then asked to retire. In their absence, my first inquiry of counsel was whether the question of the “significance” of a similarity in the number of the alleles between Item 550 and the crime scene samples, (about which Mr Goetz was being invited to give an opinion, and as to which I understood Dr Walsh would also be invited to offer an opinion when he was called to give evidence) had been the subject of evidence before Johnson J and, if so, whether it had been resolved by his Honour when the accused’s pre-trial application for the exclusion of “the DNA evidence” was dismissed in April 2014. I was initially told by both counsel it had not been, however, that position was later revised when counsel had the opportunity to review his Honour’s judgment.

10. [28]

    The Crown submitted that his Honour had comprehensively addressed all issues bearing upon the admission of the evidence of Mr Goetz and Dr Walsh, and that he exhaustively addressed the various bases upon which their evidence might be excluded in the exercise of the discretions in ss 135-137 of the Evidence Act. In those circumstances, the Crown submitted that I should regard myself as bound by his Honour’s pre-trial ruling, consistently with the operation of s 130A of the Criminal Procedure Act. That section provides:

11. [29]

    Mr Turnbull submitted that the way in which the challenge to the evidence of Mr Goetz and Dr Walsh has emerged in the trial would satisfy me that it is not in the interests of justice for his Honour’s order to bind me as the trial judge. Mr Turnbull placed particular emphasis on Mr Walton’s evidence, set out above, and what the Crown ultimately accepted in argument was the separate and distinct impact of Dr Perlin’s evidence at trial in contrast to what his Honour found at [427] to be the cumulative effect of the totality of the expert DNA evidence favouring the admission of all the DNA evidence under challenge.

12. [30]

    Mr Turnbull conceded that the challenge to the admissibility of the evidence of Mr Goetz and Dr Walsh under s 79 of the Evidence Act was not advanced with sufficient precision before his Honour. He submitted that alone would justify a reconsideration of the question of admissibility. Further, he submitted that, given what he described as the “finely balanced” cases of the Crown and the defence concerning the DNA evidence with Mr Walton and Dr Perlin having already given evidence, there was a renewed need to critically review the relevance of the evidence of Mr Goetz and Dr Walsh to what remained in issue, at least as concerns the “DNA evidence”.

13. [31]

    Mr Turnbull then informed me that the accused accepts that, based upon Dr Perlin’s statistical analysis using TrueAllele with the DNA profiling of Item 550 by Mr Walton used for the purpose of inferring genotypes in his statistical modelling, the jury could comfortably find that the DNA of the three deceased males forms part of the mixed DNA profile in Item 550. What Mr Turnbull submitted was the relatively low statistical probability of the deceased females also being represented in Item 550 remained in contest given Dr Perlin’s evidence to the opposite effect. As Mr Turnbull expressed it, “the battle lines” are more starkly drawn on the question whether Item 550 is blood, that is, whether the DNA of the deceased (the three deceased males from the accused’s perspective and all five deceased on the Crown case) in Item 550 sources from a mixture of their blood. He submitted that the evidence of Mr Goetz and Dr Walsh, properly understood, was not capable of proving, directly or indirectly, the number of people who contributed DNA to Item 550, their identity or that Item 550 was blood or contained blood and that their evidence did not meet the test of relevance in s 55 of the Evidence Act for that reason.

14. [32]

    In the course of argument I indicated to counsel that there was force in Mr Turnbull’s submissions that s 130A(3) of the Criminal Procedure Act had been enlivened, in particular, since the Crown had made clear in submissions before me the purpose to which the evidence of Mr Goetz and Dr Walsh would ultimately be put by the Crown and the reasoning the jury would be invited to apply to it in resolving the facts in issue.

15. [33]

    I have already expressed the view that his Honour’s admission of the evidence of Dr Walsh as expert opinion evidence does not appear to have been the subject of developed submissions by either the Crown or the accused in the pre-trial hearing. In particular, there appear to have been no detailed submissions referable to the use to which his evidence of a high degree of similarity between Item 550 and the crime scene samples can permissibly be put by the Crown in proof of its case, an enquiry integral to the question whether his opinion is admissible under s 79 of the Evidence Act. (I note that his Honour made no discrete finding as to whether Mr Goetz’s evidence satisfied the test for admission under s 79.)

16. [34]

    In Gilham v R [2012] NSWCCA 131; 224 A Crim R 22, the Court observed at [333]:

17. [35]

    The Court also noted that, at the appellant’s trial, it appeared to have been accepted by trial counsel that observations by a forensic pathologist that there was a “similarity” in the knife wounds suffered by the deceased was opinion evidence (even if the transparencies revealing the location and distribution of the knife wounds might equally be a lay opinion or conclusion of fact) and, that being the case, by operation of s 76 of the Evidence Act, the opinion was not admissible to prove the fact of similarity of wounds or a wound pattern unless the exclusionary rule in s 79 was satisfied. The Court went on to find that the evidence did not satisfy the test for admission as opinion evidence (see [330]-[350]). Although that decision does not dictate the resolution of the challenge mounted by the accused here, the Court’s principled approach to the admission of expert opinion evidence applying Dasreef Pty Ltd v Hawchar [2011] HCA 21; 243 CLR 588 (an approach confirmed in Honeysett v R [2014] HCA 29; 253 CLR 122) is apposite.

18. [36]

    In all the circumstances, not least being the timing of the objection with the Crown case almost complete, I am satisfied that it would not be in the interests of justice for his Honour’s pre-trial orders concerning the admissibility of the evidence of Mr Goetz and Dr Walsh to bind me and that I should determine that question afresh.

19. [37]

    The question asked of Mr Goetz to which objection was taken, set out above, was redefined by the Crown Prosecutor in the course of submissions in the absence of the jury as follows:

20. [38]

    I understood the Crown’s reference to “two unrelated scenes” in the redefined question he proposed to ask Mr Goetz (and I assume of Dr Walsh) to mean two geographically distinct localities at which biological material has been sampled for DNA profiling. Assuming, as I did at that time, that Mr Goetz would give evidence that he had not previously seen “that degree of similarity in the number of alleles and their peak heights in two different geographical locations”, I raised with the Crown what he considered would follow from that evidence in proof of a fact or facts in issue in the trial. The Crown then made it clear that he proposed to invite the jury to use Mr Goetz’s evidence of the degree of similarity (in particular between Items 616 and 550) in “a practical way” to permit them to reason to the conclusion that the accused’s garage and the crime scene at Boundary Road are not unrelated scenes, but rather that the accused had transferred the blood of the deceased from the crime scene to his garage and that, despite his efforts to clean any blood residue from his clothes and/or the weapon or weapons he used to murder the deceased, he had inadvertently left their blood on the garage floor. The Crown submitted that evidence of the fact and degree of similarity between Item 550 and the crime scene samples to be given by Mr Goetz and Dr Walsh, and their opinion as to the significance of that fact, is “a practical way of giving some significant information to the jury to enable them, for themselves, to assess [the] significance of the DNA evidence”.

21. [39]

    It was agreed at that time that further submissions concerning the admissibility of Mr Goetz and Dr Walsh’s evidence should await Mr Goetz being invited in conference with the Crown to consider the question the Crown proposed to ask him (and for an additional statement to be served on the defence) and for the Crown to confer further with Dr Walsh if this was considered necessary. Over the course of a number of days thereafter, a series of emails were exchanged between Mr Goetz and the solicitor instructing the Crown Prosecutor and served on the accused.

22. [40]

    As to the precise question the Crown proposed to ask Mr Goetz, the defence were advised he would say as follows:

23. [41]

    The Crown’s instructing solicitor then forwarded a further email, in which Mr Goetz was invited to address a question by return email, no doubt for the purposes of it being served in the form of a written opinion on the accused. The question was directed to his opinion as to the degree of similarity between Item 550 and Item 616 (and Items 47 and 223), as compared to the degree of similarity he regularly observed in multiple contributor samples from the same crime scene. Mr Goetz provided the following written response:

24. [42]

    A further email was sent by the ODPP asking Mr Goetz to further refine his opinion in the following terms:

25. [43]

    By return email, Mr Goetz said as follows:

26. [44]

    The redefinition of the Crown’s question, and the further enquiries made of Mr Goetz by email, should be viewed against the fact that in August 2013 (that is, before he gave evidence in the pre-trial hearing but following his evidence at committal proceedings) he informed the solicitor for the ODPP that he was unable to provide any comment about the similarity of alleles between the samples taken at the scene and at the garage because he could not apply any statistical weight to the fact or features of the similarity he observed. He went on to say:

27. [45]

    When he was then asked by the Crown Prosecutor, Ms Shead, about the significance of the comparative allele numbers and their peak heights, he confirmed the advice he had provided to the ODPP. He said:

28. [46]

    In cross-examination by Mr Turnbull in the pre-trial hearing, Mr Goetz emphasised that he had made no statistical analysis of the similarity that he had observed in the profiles generated by Mr Walton. He also gave the following evidence:

29. [47]

    Later in cross-examination, when taken to his advice to the Crown in the email of August 2013 referred to above, Mr Goetz said:

The Crown’s intention to call Dr Walsh

1. [48]

   In the course of argument concerning the admissibility of Mr Goetz’s further evidence, the Crown advised me of its intention to call Dr Walsh to give similar evidence to that of Mr Goetz, consistent with Dr Walsh’s evidence at the pre-trial hearing that he observed what he described as “a very high degree of similarity” between the DNA profile generated from Item 550 and the crime scene samples and, in particular, the DNA profile generated from Item 616. Although at the time that the objection was taken to Mr Goetz’s evidence Dr Walsh had not given evidence, as the argument developed, the parties agreed the admissibility of the evidence from both witnesses could be resolved by reference to their evidence at the committal and at the pre-trial hearing (inclusive of the emails from Mr Goetz) without the need to convene a hearing on the voir dire.

2. [49]

   Dr Walsh’s evidence on the issue of similarity was first served in the form of a joint report with Dr Taylor and Dr Buckleton (neither of whom is to give evidence in the trial), dated September 2013. That report provided:

3. [50]

   In that report, Dr Walsh’s qualifications are summarised with a curriculum vitae as an addendum to the report. That addendum is not before me. Relevantly, his qualifications include a Bachelor of Science (Anatomy) with first class Honours and a PhD in Forensic Science. He commenced his forensic career at the John Tonge Centre for Forensic Sciences (Qld) in 1994 and with the Australian Federal Police in November 2006. Between 1994 and 2006, he held a number of operational and academic roles in forensic science. He has supervised DNA analysis in over 2,000 criminal cases and given expert evidence on more than 50 occasions. He has expertise in “forensic DNA statistics” having researched and taught (including training forensic and legal professionals in Australia and globally) and has published internationally on the subject.

4. [51]

   In his evidence at the pre-trial hearing, Dr Walsh gave the following additional evidence concerning his expertise:

5. [52]

   In re-examination, Dr Walsh was asked about his experience in undertaking a comparative analysis of mixed DNA samples, he said:

6. [53]

   In re-examination, he confirmed that he had not previously commented upon, or had occasion to comment upon, any similarity between mixed contributor DNA samples beyond three contributors, as to which he said:

7. [54]

   In his evidence in chief, he gave the following evidence on the issue of similarity:

8. [55]

   In cross-examination by Mr Turnbull, Dr Walsh rejected the suggestion that points of dissimilarity in the number of alleles between Items 550 and 660 undermined his opinion that the profiles were similar “to a significant degree”. He did accept, however, that he was unable to apply any statistical or objectively verifiable weight to what he described as his “face value” observation of the similarity in the number of shared alleles and their relative proportions. He was asked these questions:

9. [56]

   Later in the cross-examination, Dr Walsh explained that the basis for his opinion as to the relative similarities in allele numbers and their peak heights was not because of any assumption he had made about the relative concentration of DNA in Item 550 and the crime scene sample, but, as he explained:

10. [57]

    When he was asked to explain what he meant by the similarity being significant (in the sense that his observation was significant), he said:

Does the evidence of Mr Goetz and Dr Walsh meet the test for admission under the Evidence Act?

1. [58]

   The first inquiry is whether the evidence the Crown proposes to lead from Mr Goetz and Dr Walsh (whether in whole or in part), if accepted by the jury, has the capacity, directly or indirectly, to rationally affect their assessment of the probability of the existence of a fact in issue. This, in turn, requires identification of the fact or facts in issue in the trial to which the evidence is said to be relevant.

2. [59]

   The accused’s written submissions concede that the evidence of both Mr Goetz and Dr Walsh satisfies the test of relevance in s 55 of the Evidence Act. As Mr Turnbull developed his submissions, however, the identification of the fact or facts in issue to which it is said that at least Mr Goetz can give relevant evidence was limited to his evidence that the 75 alleles in the blood of the five deceased were represented in Item 550, consistently with the evidence given by Mr Walton concerning that feature of similarity in the EPGs he generated. As I have noted and analysed, there was no objection at trial to Mr Walton’s evidence to that effect.

3. [60]

   However, the evidence that the Crown proposes to lead from Mr Goetz is not limited to his observations of the similarity in the numbers of alleles and their respective peak heights between the crime scene samples and Item 550 (assuming that is properly described as requiring an expert opinion, as to which see later in this judgment). The Crown also intends to lead evidence from him that the degree of similarity is “significant” and, if permitted, evidence from Dr Walsh that the degree of similarity was, in his assessment, “very high”. (Mr Goetz also described the degree of similarity as “unusual” or “remarkable” in his evidence at the pre-trial hearing, although I do not understand that the Crown intends to lead this evidence before the jury.)

4. [61]

   It is that aspect of the evidence of both witnesses that Mr Turnbull submitted was inadmissible opinion evidence. His primary submission is that, to the extent that Dr Walsh’s opinion is based upon his expertise as a forensic biologist specialising in DNA analysis with some exposure to the interpretation of mixed contributor samples (at least in cases of up to three contributors), it is an opinion that lacks scientific rigor, there being no statistical analysis or objective test of any kind, against which his opinion that the degree of similarity was “very high” can be meaningfully tested or validated, and is not admissible as opinion evidence for that reason.

5. [62]

   Mr Turnbull’s submission seems to parallel an argument most recently advanced in the course of argument in the High Court in Honeysett to the effect that an opinion that is “not amenable to elaboration” or to “measurement and calculation” is not an opinion that is wholly or substantially based on “specialised knowledge”, there being no independent means of gauging the reliability and validity of an opinion based on that knowledge. The High Court declined to rule upon whether an opinion based on specialised knowledge for the purposes of the application of the exclusionary rule in s 79 of the Evidence Act requires an independent means of validation, with the issues on the appeal not providing an occasion for the Crown to consider that question (see Honeysett at [42]).

6. [63]

   I also note that, since Honeysett was decided, the Supreme Court of Victoria in DPP v Tuite [2014] VSC 662 was invited to consider whether the language of s 79 allows for “reading in” a test of evidential reliability as a condition of admissibility but declined to do so. They followed a line of precedent in this Court and in the High Court that s 79(1) contains its own specification of the requisite foundation for the witness’ “knowledge”, namely that it must be based on the person’s training, study or experience and that reliability or validation are extraneous considerations. The Court went on to find at [77]:

7. [64]

   In light of the state of the authorities, the primary submission as part of Mr Turnbull’s challenge to the admission of the evidence of Mr Goetz and Dr Walsh must be rejected.

8. [65]

   In Honeysett, the Court reviewed the operation of s 79 of the Evidence Act consistently with its decision in Dasreef, restating the test for admissibility as follows:

9. [66]

   Mr Turnbull submitted that the Crown has failed to satisfy the first limb of the test for the evidence to be admitted as expert opinion evidence having failed to identify a “field of specialised knowledge”, or an identified aspect of any “field of specialised knowledge”, in which Dr Walsh has “specified training, study or experience”, to permit him to offer an opinion as to the significance, by extent or degree, in the similarities of the comparative mixed DNA profile analysis of Item 550 and the crime scene samples. Mr Turnbull submitted that the only standard by reference to which Dr Walsh sought to defend his opinion was what he claimed to be his experience in having seen complex mixed DNA profiles in some cases where sampling has occurred at the one location or at the one crime scene. Mr Turnbull submitted that for Dr Walsh to express the opinion that the similarity he observed between samples in this case to be of a “very high degree”, where he has no specialised knowledge in comparative mixed profile analysis from which his opinion derives, deprives his opinion of the legal prerequisite to justify its admission as expert opinion evidence under the exception in s 79 of the Evidence Act.

10. [67]

    By contrast, Mr Turnbull embraced what he regarded as the principled and qualified way in which Mr Goetz expressed his view as to the significance he observed in the similarity between the DNA profiles in his evidence at the pre-trial hearing, with his ultimate position being that he was not prepared to offer any opinion, from a scientific perspective, as to the significance or importance of the similarity between Item 550 and the crime scene samples as he did not have the expertise to make that judgment. Mr Turnbull submitted that, as recently as July this year, in the last email exchange with the ODPP set out above, Mr Goetz has consistently resisted being drawn to offer a view about relative degrees of similarities.

11. [68]

    In the pre-trial ruling, Johnson J cited R v Dlugosz; R v Pickering; R v S(MD) [2013] 1 Cr App R 32 as support for admission of the evidence of Mr Goetz and Dr Walsh as expert opinion evidence, despite their evidence not involving any statistical comparison as an objective standard of similarity. I have read and considered that decision. While I have an appreciation as to why the Court of Appeal in that case held that an “evaluative opinion” of the features of a mixed DNA profile without reference to a statistical database, was admissible because there was “a sufficiently reliable scientific basis” for it to be expressed as an opinion, I do not consider that reasoning is of any utility in deciding whether expert opinion evidence satisfies the test for admission under the exception to the opinion evidence rule in s 79 of the Evidence Act.

The Crown submissions

1. [69]

   I invited the Crown to point to any particular feature of Dr Walsh’s academic or professional experience as a forensic scientist specialising in DNA analysis which qualified him to undertake a comparative DNA profile analysis between mixed profile samples taken from within a crime scene and from a geographically distinct location. None was identified. That being the case, I am not satisfied that he has specialised knowledge of a kind upon which to base his opinion that the similarities in the profiles were to a “very high degree”. In the result, the Crown is not permitted to lead evidence from either Mr Goetz or Dr Walsh of the degree or extent of similarity they observed in the mixed profile samples generated by Mr Walton.

2. [70]

   Although the Crown conceded in argument that Dr Walsh has no experience in undertaking any comparative analysis of this kind, the Crown submitted he should nonetheless be permitted to give evidence that the degree of similarity he observed between Item 550 and the crime scene samples as mixed DNA contributor samples is a degree of similarity that is commonly encountered in mixed contributor samples taken within the same crime scene (where either blood or other human biological material is shed in the course of a crime event involving either multiple offenders or multiple victims).

3. [71]

   In my view, for Dr Walsh to be permitted to give that evidence, having not encountered mixed DNA contributor samples from two apparently unrelated crime scenes for comparison purposes is a different way of expressing the opinion I have determined he should not be permitted to give.

4. [72]

   The Crown then sought to confine the evidence from Mr Goetz and Dr Walsh to their observations that the number of alleles and their peak heights in the DNA profiles they reviewed were “similar” as an observation they commonly encountered in samples taken from the same crime scene, to support the Crown case that, although Item 550 was sampled from a place geographically distinct from the crime scene and, in that sense, “unrelated” to it, it was in fact circumstantially related locations by reason of the accused having transferred the blood of the deceased, containing their DNA, from where they were killed to his garage floor.

5. [73]

   In Mr Turnbull’s submission, the assumption underpinning what is said to be the limited evidence the Crown wishes to lead from Mr Goetz and Dr Walsh is that the DNA profiles they reviewed are said by the accused to be “unrelated”, when it is the reason for them being related that is one of the facts in issue in the trial. On the Crown case, the deceased’s DNA in a mixture in a stain on the floor of the accused’s garage is “related” to their DNA deposited in blood at the crime scene because the accused transferred the blood of the deceased from the crime scene to his garage, while, on the defence case, the possibility of secondary transfer of some, if not all, of the DNA of the deceased, not in their blood, and the incidental or random deposition of the DNA on the floor in the area that was sampled, could not be excluded as a reasonable possibility.

6. [74]

   With the competing submissions poised in that way, it became clear that the Crown also intended to rely upon the evidence of Mr Goetz and Dr Walsh to support the jury drawing the inference that the similarities in the DNA profiles (that is, the number of alleles and their peak heights) was evidence they were entitled to take into account in determining whether Item 550 was in fact blood or, more pointedly, the blood of the deceased.

7. [75]

   The Crown Prosecutor conceded as much when I queried whether there was a hidden assumption that Item 550 was in fact blood, as to which the Crown said as follows:

8. [76]

   That submission raises the question whether the evidence of Mr Goetz and Dr Walsh, limited in the way the Crown proposes, is admissible to support the reasoning which the Crown will urge the jury to apply, or, to put it another way, whether together with other evidence in the Crown case, it has the capacity to displace any reasonable possibility that there has been occasional, incidental and temporally unconnected transfers of the DNA of the deceased (or some of them) in human biological material that is not blood.

9. [77]

   The exclusion of the opinion evidence of Mr Goetz and Dr Walsh concerning the extent or degree of similarity between Item 550 and various of the crime scene samples because it does not qualify for admission under s 79 of the Evidence Act does not necessitate withdrawing from the jury’s consideration Mr Goetz’s evidence that the number of alleles and their relative peak heights in the samples he considered were “similar” in number and pattern. Although the accused’s written submissions seek the exclusion of “any evidence from Mr Goetz and Dr Walsh that the DNA sample found in the garage (Item 550) shares any similarity to any sample found at the crime scene”, there is no application to withdraw from the jury’s consideration Mr Walton’s evidence to the same effect as Mr Goetz’s evidence extracted above. The fact that a similarity in allele number and their peak heights is not determinative of the number of individual contributors to the mixed DNA profile in Item 550, as Mr Walton accepted in cross-examination, is not to the point.

10. [78]

    In Marsh v R [2015] NSWCCA 154, Harrison J (with whom Simpson JA and Adamson J agreed) noted:

11. [79]

    I am satisfied that the Crown is entitled to use the objective fact that there are features of similarity in allele number and their peak heights across the various samples identified in the evidence of Mr Goetz and Mr Walton in support of an argument that, together with other facts and circumstances relied upon by the Crown (some of which derive from the scientific evidence already before the jury), and the inferences that may legitimately be drawn from those facts and circumstances, Item 550 contains the DNA of each of the deceased and, from proof of that fact, that the DNA sources from the blood of the deceased.

12. [80]

    Analysed in that way, the fact of similarity in allele numbers and their peak heights observed by Mr Goetz satisfies the test of relevance in s 55 of the Evidence Act, comprising, as it does, part of the evidence available to the Crown to prove those facts in issue as part of proving the accused’s guilt as the ultimate fact in issue.

13. [81]

    I am also satisfied (there being no submission to the contrary) that Mr Goetz’s evidence as to the fact of similarity in allele numbers and their relative peak heights across the samples he reviewed satisfies the exception to the exclusionary rule in s 79 of the Evidence Act, being an opinion that is based “wholly or substantially” on his “training, study and experience” in DNA analysis.

14. [82]

    As I read the evidence led from Dr Walsh on the pre-trial hearing and his report of September 2013, he does not observe, note or comment upon the fact of a similarity in the DNA profiles he reviewed per se. Rather, he was specifically asked to offer an opinion as to the significance of what Mr Walton and Mr Goetz observed, an opinion which, expressed in qualitative terms, transgresses s 79 of the Evidence Act.

Whether the probative value of the evidence is outweighed by unfair prejudice

1. [83]

   In the Dictionary to the Evidence Act, “probative value” is defined to mean “the extent to which the evidence could rationally affect the assessment of the probability of the existence of a fact in issue”.

2. [84]

   In Adam v The Queen [2001] HCA 57; (2001) 207 CLR 96, Gaudron J at [59]-[60] observed:

3. [85]

   The accused submitted that the probative value of the evidence of similarity is “very low” whilst the danger of unfair prejudice is “very high”, there being a real danger that the jury will give the evidence “more weight than it deserves”. The accused’s written submissions directed to the exclusionary discretion in s 137 of the Evidence Act focused largely on the extent or significance of similarity and whether, even if the evidence of Mr Goetz and Dr Walsh as to that fact qualified as opinion evidence under s 79, it should be excluded because its probative value was outweighed by the danger of unfair prejudice. However, some of the features of their evidence identified as being productive of unfair prejudice also focused on the bare or objective fact of “similarity”. In that connection, it was submitted that there was a real danger that the jury would misuse the “similarity” about which Mr Goetz and Dr Walsh speak to compromise the need to scrutinise Dr Perlin’s evidence with care and, further, that they may fail to appreciate the limits on the way in which Dr Perlin’s statistical analysis of likelihood ratios can be put in proof of the Crown case, importantly since he provides no statistical analysis of a “whole sample to whole sample comparison”.

4. [86]

   The accused also submitted that there is also a real danger that the jury will impermissibly reason to the conclusion that, because there is a commonality or similarity in allele numbers in Item 550 and various of the crime scene samples, this constitutes a “direct match” of sample to sample, leading them to conclude that the DNA of each of the five deceased is in Item 550, when the evidence does not allow for that conclusion to be reached by that reasoning. The accused identified the further risk that that degree of similarity may be misused by the jury to conclude, again from that fact alone, that the DNA must have been deposited in blood because it must have come from the crime scene. In summary, it was submitted that the “similarity evidence” carries with it a risk of offering to a jury a deceptively simple basis upon which to resolve, as facts in issue adverse to the accused, both the fact that Item 550 is in blood and that it contains the DNA of the deceased, a reasoning which would be irrational.

5. [87]

   It has been long recognised that DNA evidence the subject of contest in a criminal trial is often complex, with the potential to be misunderstood by a jury (Aytugrul v The Queen [2012] HCA 15; 247 CLR 170). The need for scientific principles to be explained to a jury in a manner that they can understand, and in a way that enables them to apply their understanding to the facts in issue in a trial, is part of the challenge left to the trial judge.

6. [88]

   I accept that evidence of similarity (in the way in which that concept derives from the evidence under challenge) may, in the absence of careful direction, be afforded undue weight by the jury. However, I am of the view that with the probative value of the evidence, assuming the inferences most favourable to the Crown are drawn, being high, it is a danger against which carefully structured directions can protect and, on that basis, I am not satisfied that the evidence should be excluded in the exercise of discretion.

Coincidence reasoning

1. [89]

   The accused submitted that the evidence of similarity, even if it is confined to the objective features of similarity in the various DNA profiles in both allele numbers and their peak heights, is being utilised by the Crown for a coincidence purpose in the sense that the Crown is inviting the jury to find that it is improbable that mixed contributor samples from the crime scene and from the garage floor exhibiting the features of similarity which Mr Goetz and Mr Walton identify are related to one another by coincidence. Put another way, it was submitted that the Crown will invite the jury to find that the mixed contributor samples are not “coincidentally” similar by reason of a secondary or random transfer of DNA in sweat, saliva or skin cells, but that DNA profiles from the blood of the deceased were transferred from one geographical site to the other by the accused following the murders. That being the case, it was submitted that admission of the evidence of similarity must comply with the coincidence rule in s 98 of the Evidence Act.

2. [90]

   Despite the fact that the Crown may resist any suggestion that the evidence is to be led for a coincidence purpose, if there is an invitation to the jury to apply the reasoning the accused attributes to the Crown, the Court is obliged to consider the effect of that evidence to determine whether it is in fact led for a coincidence purpose and, if so, to determine whether it satisfies the test for admission in s 98 of the Evidence Act.

3. [91]

   The accused submits that:

4. [92]

   I have expressed a preliminary view that, leaving aside the absence of any formal notice as required by s 98(1)(a), the evidence would seem to me to satisfy the dual tests in ss 98(1)(b) and 101(2) of the Evidence Act. However, the Crown has asked to be heard further as to whether the coincidence rule is invoked at all, in which case I reserve any final view on the question until I have heard further from the Crown.