Admissibility of geo-location evidence: New VSCA decision

An increasing feature of criminal trials, where identity of an offender is in issue, is evidence of geo-location data extracted from mobile phones. This data often comes from ‘Call Charge Records’ produced by a cellular network.

The relevance of the evidence is usually that the records are consistent with an accused’s mobile phone being in a particular geographic area at a particular time, leading to the inference that the accused was in that same area at the time.

The continuing question is if and how these records can be used as evidence in a trial.

The records are produced by the telecommunications network provider (e.g. Telstra, Optus, Vodafone). They ought ordinarily be accompanied by an evidentiary certificate.¹

Authenticated by certificate, the records are likely to overcome the hearsay rule at trial by being ‘business records’.²

It has been the general approach that the raw data, alone, is of little use to a jury. The practice has been for the party relying on the evidence to adduce it through a telecommunications engineer or other specialist, who can explain what the data means and, importantly, its limitations. Experts like Dr Matthew Sorrell have become regular witnesses in these trials.³

This has been prompted by the evidence’s treatment by courts. In Ward v The Queen (2018) 55 VR 307, the Victorian Court of Appeal observed (esp. at [85]-[86]) such experts were necessary, because any evidence concerning the inferences that can be gleaned from the data is opinion – presumed inadmissible, but with an exception to that presumption available for experts.⁴

But a decision of that Court late last year has potentially walked back the level of expertise required for geo-location evidence to be admitted at trial. In Moorhouse (a pseudonym) v The King [2025] VSCA 329, the Court held that geo-location evidence was admissible in a case where it was produced by a police officer experienced and trained in working with the data, but who was not a telecommunications expert or engineer.

The opposing argument had been that the defence were denied the opportunity to cross-examine on the reliability of the evidence because the officer did not have the requisite expertise. Exclusion was sought, principally under s 137 of the Evidence Act.

The Court in Moorhouse held that the officer had sufficient specialised knowledge to produce the data by reason of his experience (at [37]). The danger of unfair prejudice to the accused was low, in part because the officer was capable of giving evidence about the limitations of this type of evidence (at [43]). And any limitations on their expertise could, itself, be subject of cross-examination.

The Court also addressed the admissibility of a video produced by the police witness, which showed a rolling map representation of the call charge record data. This was admissible in so far as it directly and faithfully reproduced the raw data (at [55]-[64]).

The decision is likely to mean that in more routine cases that rely on geo-location data, the prosecution will rely more on internal police witnesses with experience of geo-location data, rather than engaging expensive specialists in the field.

1. Under s 185A of the Telecommunications (Interception and Access) Act 1979 (Cth). ↩︎
2. Uniform Evidence Acts, s 69. ↩︎
3. See, for example, Liam Beatty, ‘Greg Lynn trial: Pilot’s phone off for 46 hours as Russell Hill and Carol Clay’s bodies burnt, jury told’ (NCA NewsWire, 27 May 2024). ↩︎
4. Uniform Evidence Acts, ss 76, 79. ↩︎