R v Wrigley (No 3)

1. [1]

   HIS HONOUR: The accused, Clinton Wrigley, is on trial on a count of murder, namely, that on or about 23 January 2023, near Nyngan, he murdered Joel Carter (the deceased). There are three other counts on the indictment, involving the theft and/or disposal of property that was allegedly taken from the deceased’s residence, at about the time of his death.

2. [2]

   The allegation in the Crown case is that on the evening of 22 and 23 January (all dates in this judgment are for the year 2023, unless otherwise stated), the accused, who was aged 37 at the time, drove to a remote rural property known as Rosehill where the deceased, aged 59, was residing alone, and killed him by inflicting blunt force head injuries. He stole a Toyota HiLux (the HiLux) and some Milwaukee-brand tools that had belonged to the deceased. He destroyed the HiLux by setting fire to it on a backroad in the early hours of the morning of 23 January and later sold some of the tools.

3. [3]

   The Crown case, other than evidence of alleged admissions made by the accused to others, is circumstantial in nature. The Crown will seek to establish that the accused was in the vicinity of Rosehill at the relevant time by evidence that includes expert forensic evidence as to the whereabouts of two mobile phones that the accused is alleged to have used in the early hours of 23 January, the content of text messages and times of certain calls made between those phones and others and the evidence of a witness who is subject to a non-publication order, and who I will refer to for that reason as witness A.

4. [4]

   The accused has served a notice of alibi on the Crown, asserting that from about 11.30pm on 22 January to about 8am on 23 January, he was in his vehicle, a Toyota Tarago van (the Tarago) which was parked in a specified area of bushland just outside the township of Nyngan, other than between about 12.30am and 2.30am, when he walked into the Nyngan township and back again.

5. [5]

   The Crown alleges that on the morning of 23 January, the accused used two mobile phones, which the accused disputes he possessed at that time, to send text messages and make voice calls to witness A and the accused’s partner, Natalie Riley, who resided at Warren. One phone operated on the Telstra cell phone network (the Telstra phone) and the other on the Optus network (the Optus phone). The Crown will seek to establish by evidence of a telecommunications expert, Professor Aruna Seneviratne, that the antennae on cell towers with which the mobile phones connected was consistent with the Crown case as to the whereabouts of the two phones over a period of about five hours on the morning of 23 January, and inconsistent with them being at the alibi location.

6. [6]

   The accused challenges the admissibility of parts of Professor Seneviratne’s evidence as outlined in his evidence on the voir dire and aspects of two reports by him. The first report is dated 10 February 2025. The second is undated; it was admitted into evidence on 7 April 2025, which was the second of two days of Professor Seneviratne’s evidence on the voir dire. He gave his evidence remotely via audio visual link and was unable to transmit a signed copy to the Crown, but since he adopted the report in his evidence, no objection was taken to its admission into evidence.

7. [7]

   On 15 April 2025, I made an order that the opinion of Professor Seneviratne as to the probability of a mobile phone being, or not being, in certain locations at particular times was admissible. I have also determined that Professor Seneviratne’s opinion that the Telstra and Optus phones were effectively in the same location at certain times is inadmissible. These are my reasons for those determinations.

8. [8]

   The defence did not challenge Professor Seneviratne’s claim to have specialised knowledge in the area of mobile telecommunications based on his training, study or experience, which was set out in his first report. Professor Seneviratne is an electronics engineer. He has an honours degree in electronic engineering and a Doctorate of Philosophy in communications systems. He holds various senior positions in research agencies involved in communication technologies and has worked for, and held fellowships with, private telecommunication firms in Australia and overseas.

9. [9]

   The relevant part of the Crown case, by way of background for the purposes of this voir dire, is as follows.

10. [10]

    The accused resided in Warren with Ms Riley. He was a truck driver and farm hand. The Crown anticipated that witness A would give evidence to the effect that he worked on the Rosehill property growing crops and agisting sheep, by arrangement with the deceased and his father, Owen Carter, who owned both Rosehill and an adjoining property, named Neeroc. Witness A and the accused preferred to reside at Neeroc while working on Rosehill, sleeping in their vehicles there. The deceased resided at Rosehill by himself.

11. [11]

    The two properties are about 20 to 25km from Nyngan. To drive from one property to the other using public roads takes about 14 minutes, driving at 50-60kph. There were dirt roads on the properties on which a vehicle could drive from the Rosehill house to where the accused was staying at Neeroc at the same speed in about 10 minutes. To walk that distance across the properties, at 5kph, would take about 1 hour and 36 minutes.

12. [12]

    On Sunday 22 January, at about 9.16pm, witness A and the accused drove into Nyngan from Neeroc, for dinner and a shower at the BP service station (the BP) and returned to Neeroc. At about 11.30pm, the accused told witness A that he was going to look for a stolen quad bike. He drove off in the Tarago.

13. [13]

    The following morning, at about 2.30 to 2.35am according to witness A, he was woken by a phone call from the accused, who asked him for directions to Warren from a back road, which witness A provided. I note the Crown case is that witness A was mistaken as to the time of the call; phone records indicate the first call he received on that date from a phone that, in the Crown case, was associated with the accused, was at 3.40am.

14. [14]

    At about 5.28am, witness A was again woken by a phone call from the accused, who told him that he needed a lift back to Neeroc from the back road from Nyngan to Warren. Witness A then noticed that the Tarago was at Neeroc, parked near witness A’s truck. Witness A left Neeroc at about 5.45am in his vehicle (the Landcruiser) to pick up the accused.

15. [15]

    The Crown case includes evidence to the effect that at about 5.53am, a driver on the Old Warren Road, between Nyngan and Warren, observed a vehicle off the road to be on fire, with no-one around. It was the Hilux (the HiLux fire site).

16. [16]

    Witness A searched for the accused unsuccessfully for about 60km along the Warren-Carinda Road, between Nyngan and Warren, thinking that was the road that the accused said he was on. He returned to Neeroc at about 7.10am. His phone was flat, so he recharged it. When he turned it back on, at about 7.33am, he noticed he had three missed calls from the accused. Shortly afterwards, he spoke to the accused, who told him that he was along the Old Warren Road from Nyngan, which was a road not known previously to Witness A. Witness A drove to that road and picked up the accused at about 8.10am, after receiving a message from the accused that he had driven past him. They arrived at Neroc at about 8.34am.

17. [17]

    On the same day that witness A made his statement to police, he drove with police to a location where he said that he picked up the accused (the pick-up point) and participated in a brief videoed explanation on site, which was about 15km from Nyngan and 12.2km from the Hilux fire site, which was further along that road from Nyngan.

18. [18]

    The Telstra phone connected to satellite by GPS on two occasions on the Old Warren Road between the pick-up point and the HiLux fire site. The first was at 7.31am about 6km from the HiLux fire site towards Nyngan and the second was at 7.48am about 6.2km from the HiLux fire site towards Nyngan.

19. [19]

    On the morning of 23 January, between 4.19am and 7.26am, there were eight voice calls and 15 failed voice calls between either the Optus or Telstra phone, and Ms Riley’s phone. As well, Ms Riley’s phone sent texts to the Optus phone at 7.21am (“What road?”) and at 7.26am (“Txt me where”, “I’m comin” and “On my way”).

20. [20]

    In his first report, Professor Seneviratne stated that he was first retained to advise the police in respect of this matter on 23 January 2025. He recited the request he received from the Officer-in-Charge of the investigation, Detective Sergeant Bradley Gardiner (DS Gardiner), to analyse certain cellular data to achieve the following five goals:

21. [21]

    The evidence summary referred to in (e) was a document composed by DS Gardiner. It included eight opinions by DS Gardiner as to the locations of the accused’s Telstra phone and 15 opinions as to the locations of the accused’s Optus phone at specific times, based on “a review of the mobile telecommunication service” activating a specific antenna on a named cell tower, over a period of approximately 12 hours, from 10.56am on 22 January to 10.42am on 23 January. The mobile’s locations were expressed by DS Gardiner as being “consistent” or “inconsistent” with certain locations, although it was not suggested that DS Gardiner had expertise in the area of telecommunications involving the interpretation of data concerning the possible whereabouts of mobile phones.

22. [22]

    In his first report, Professor Seneviratne stated that all of DS Gardiner’s opinions as to the locations were accurate. He added the following opinions:

23. [23]

    An understanding of some basic terminology and a mobile phone’s interaction with the phone company’s equipment, as explained by Professor Seneviratne, is helpful in considering the evidence on the issues for determination. Each phone company has its own cell towers, which are also described as base stations. Antennae are attached to them, pointing in specific directions. A cell tower antenna is the communication point with a mobile phone. The direction in which the relevant antenna on the cell tower is pointing is its “azimuth”, measured in degrees from true north.

24. [24]

    One source of information as to the use of a mobile phone at a particular time is its “Call Charge Records” (CCRs) and “Reverse Call Charge Records” (RCCRs), which is information provided by the phone company that includes the cell tower and the particular antenna on it that the phone connected with. The phone company’s documentation provides the azimuth for that antenna. Another is the data held by the phone company of all interactions with the phone, including voice calls, data, texts and “handshakes”. This term was explained by Professor Seneviratne as interactions between a mobile phone and a cell tower even when the phone is not being used, provided it is turned on:

25. [25]

    In his first report, Professor Seneviratne explained how a mobile phone connects with a cell tower and the reasons that it may connect to a particular tower:

26. [26]

    In his evidence on the voir dire, Professor Seneviratne identified the material he received from police that informed his opinions. It was the CCR and RCCR records for each relevant phone; data provided by the phone companies known as LBM reports (“Location-Based Monitoring reports), two types of which were “EBM” (Event-Based Monitoring) or “LBS” (Location Based Services), which is the above-described recordings of all contacts between the phone and cell tower antennae including phone calls, sending and receiving texts and handshakes; maps showing the locations of the relevant cell towers of the relevant phone companies and the azimuth of each antenna that engaged with the phones; and some telecommunication coverage maps for the Optus cell towers.

27. [27]

    Professor Seneviratne also received, in respect of the Optus antennae, information as to range and the angle of reception and transmission of each antenna measured in degrees (the arc), for example, 68 degrees. He explained that he assumed that this meant the antenna’s azimuth was in the middle of that arc; that is, using the same example, the antenna had an area of reception and transmission that was 34 degrees to either side of the azimuth. However, he allowed for the possibility that this was incorrect, and that the measurement referred to the arc range on either side, so that, using the same example, the overall arc would be twice 68 degrees; that is, 136 degrees.

28. [28]

    Professor Seneviratne referred to matters that may impact on the range of a signal from a cell tower antenna:

29. [29]

    In cross-examination, he identified factors that may cause a mobile phone to connect to a tower that is not the closest to its location:

30. [30]

    In cross-examination, Professor Seneviratne was questioned about the reliability of an opinion that a mobile phone that is between two antennae on different cell towers that are pointing towards each other is closer to the one that is identified in the CCR and RCCR records, as was the case with an antenna on a cell tower in the Tottenham area and another on a cell tower in the area of Warren:

31. [31]

    Professor Seneviratne explained that “ping-ponging” meant:

32. [32]

    For the purposes of preparing his report, Professor Seneviratne was provided with tables of the results of sample measurements of the signal over a range of distances from particular cell-tower antennae. These tables typically had a higher number of successful samples in the mid-range of the entries for the antenna. Professor Seneviratne explained in evidence in chief that the table did not give information as to signal strength or range, although in cross-examination he conceded that it had some utility in that regard:

33. [33]

    Professor Seneviratne said:

34. [34]

    Professor Seneviratne said:

35. [35]

    Professor Seneviratne’s opinion as to consistency and inconsistency included assumptions as to signal strength. He dismissed a concern that the signal strength may be affected by maintenance being done, because in that circumstance he would expect the signal to not be operating at all.

36. [36]

    In his second report, Professor Seneviratne gave a further explanation of the process he applied in formulating his pinions in his first report. As to his opinion that the Telstra and Optus phones should be considered as a “single entity” between 11pm on 22 January and 4.17am on 23 January, he explained that it was based on the two phones repeatedly connecting to their respective towers in the same geographical area between those times.

37. [37]

    In his second report, Professor Seneviratne responded to a request to provide an opinion as to consistency or otherwise of the two mobile phones being in the area identified in the accused’s alibi notice. He explained his methodology and concluded that the device interactions for the two mobile phones were inconsistent with them being in the areas and at the times identified in the alibi notice.

38. [38]

    In his evidence on the voir dire, Professor Seneviratne tended to express his opinion as to the area in which a mobile phone was or was not, in terms of it being “likely” or “unlikely” to be in that area. He was asked what he meant by concluding that a mobile phone was “likely” to be in a particular area:

Submissions of the defence

1. [39]

   The accused’s objected to the admissibility of the opinions of Professor Seneviratne as to the following: the range, arc and/or mobile reception coverage of each tower on 22 and 23 January; as to whether the locations of the mobile phones were consistent or inconsistent with them being at a particular place; and whether the Telstra and Optus mobile phones have “similar interactions” with their respective cell towers, so that they could be considered to be in approximately the same location as each other.

2. [40]

   For the purposes of the voir dire, the accused was content to proceed on the basis that the azimuth data of the relevant antennae was correct for 22 and 23 January, although he contended that there was some doubt as to that.

3. [41]

   Essentially, the defence submitted that the location of the cell tower with which a mobile phone interacts provides little, if any, useful information as to the location of the mobile phone and is apt to mislead if considered in isolation. Sampling of the Optus cell tower antennae demonstrated that some had a range of up to 76km which contributed to the possibility that the Optus phone may not have ben connecting to the closest tower.

Determination

1. [42]

   There was no dispute, at least for the purposes of the voir dire, that both phone company’s data includes the identification of the particular antenna, and thus the cell tower, with which their mobile phone connected on each occasion that it made contact; whether for a handshake, text message, data transfer or voice message or voice call. There is also no dispute that at the relevant time the mobile phone was in a direction that is consistent with the relevant arc (whether known or not), if not the azimuth itself, of that antenna. That is because these matters are determined from working backwards from the CCR and RCCR data as to what antenna the mobile phone in question did connect with.

2. [43]

   The accused conceded that Professor Seneviratne is qualified to express opinions as to the location of the relevant cell towers, the azimuth of the connecting antenna for each interaction and the probability (expressed as “likely”, “unlikely”, or “very unlikely”) of a response by a mobile phone that is within or without the direction of the antenna. As to the Optus phone, he could give an opinion as to the range and the size of the arc.

3. [44]

   Having regard to s 79(1) of the Evidence Act 1995 (NSW), I am satisfied on the balance of probabilities that Professor Seneviratne is qualified to express opinions on those matters, based wholly or substantially on his specialised knowledge.

4. [45]

   The issue in dispute is whether, having regard to the extent of the available data, Professor Seneviratne is qualified to express an opinion as to the probability that the antenna that a mobile phone connected with was the closest antenna and cell tower to its location, or whether there could have been a closer one that it did not connect with, due to the variables discussed above, such as call congestion, obstacles and the like.

5. [46]

   The basis of Professor Seneviratne’s opinions include assumptions that may or may not be correct, such as whether there was an obstacle blocking reception with, or call congestion on, a closer tower antenna that the mobile phone was otherwise able to connect with but, due to the algorithms programmed by that phone company, the connection was made instead with a cell tower antenna that was further away but happened to be operating in approximately the same direction as the first tower.

6. [47]

   This scenario, in isolation, would suggest that Professor Seneviratne’s specialised knowledge did not better place him than someone without that knowledge to form an opinion as to whether the connecting cell tower was in fact the closest with that connective capacity. However, he explained that he took other material into account in forming his opinion, in particular, the data provided by the phone companies of all connections with the mobile phone in the relevant period. This enabled him to determine whether a connection was likely to be with the closest tower antenna or not, in broad characterisations of likely, very unlikely or likely. Professor Seneviratne’s process of reasoning was transparent, in that he was able to explain what data he took into account in arriving at an opinion as to the likelihood or unlikelihood of a phone being in a location at a particular time.

7. [48]

   Accordingly, Professor Seneviratne’s opinions as to the mobile phone date being consistent or not with certain locations are substantially based on his specialised knowledge. In my view, these opinions come within the ambit expressed in Dasreef Pty Ltd v Hawchar (2011) 243 CLR 588; [2011] HCA 21 by the majority at [37]:

8. [49]

   However, I am not satisfied that Professor Seneviratne’s specialised knowledge allows him to express the opinion that the Telstra and Optus mobile phones were, as expressed in paragraph (a) of his first report as extracted at [20] above, a “single entity”; that is, that they were effectively at the same precise locations. The evidence on the voir dire did not satisfy me that Professor Seneviratne’s opinion was, in fact, based wholly or substantially on his specialised knowledge. Rather, I am of the view that it is speculative.

Orders

1. [50]

   I made order (1) as follows on 15 April 2025 and now add order (2):

   1. (1)

      The opinions of Professor Seneviratne as to the probability of the consistency of particular mobile phones being in specified locations, is admissible.

   2. (2)

      The opinion of Professor Seneviratne as to the Telstra and Optus mobile phones being in the same specific location at the same time is inadmissible.