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District Court 15 November 2023

R v Snounou (No 1)

[2023] NSWDC 583

Drugs
EVIDENCE CRIMINAL TRIAL ADMISSIBILITY EXPERT OPINION EVIDENCE NO CONFIRMATORY TESTS UNDERTAKEN CONTROLLED PRE

Citation: R v Snounou (No 1) [2023] NSWDC 583
Court: District Court of NSW
Date: 15 November 2023
Judge(s): Sutherland SC DCJ

Background

The accused faced an indictment containing four counts relating to alleged involvement with border-controlled drugs and precursor chemicals used in the manufacture of methylamphetamine. He had pleaded guilty to two counts involving possession of iodine with intent to manufacture methylamphetamine. The remaining contested counts included an allegation that he imported benzyl cyanide, a border-controlled precursor, in June 2017.

Australian Border Force officers intercepted a consignment addressed to the accused's company and conducted presumptive tests on samples using two instruments: the FirstDefender RM (Raman spectroscopy) and the HAZMAT ID (infrared spectroscopy). Both returned presumptive positive results for benzyl cyanide. However, no confirmatory laboratory testing was undertaken, and the seized consignment, together with all samples, was destroyed by the Australian Border Force in October 2017.

The Crown sought to rely on expert opinion evidence from Dr Daniel Coghlan, a forensic chemist, to establish that the intercepted substance was benzyl cyanide. The accused brought a pre-trial application to exclude that opinion. This judgment deals only with that application.

Legal Issues

  • Whether Dr Coghlan's opinion evidence met the requirements for admissibility as expert opinion under section 79(1) of the Evidence Act 1995 (NSW), specifically whether the opinion was wholly or substantially based on specialised knowledge derived from training, study or experience.
  • If the opinion evidence were admissible, whether it should nonetheless be excluded under section 137 of the Evidence Act on the basis that its probative value was outweighed by the danger of unfair prejudice to the accused.

Decision

Issue 1: Admissibility under section 79(1) of the Evidence Act

The court held that Dr Coghlan's opinion was not sufficiently based on his training, study or experience, and that the reasoning underpinning the opinion was not adequately explained (at [131]-[132]). Dr Coghlan had conducted a visual comparison between spectra produced from a known sample of benzyl cyanide in his laboratory and the graphs produced during field testing, but no scientific reasoning, peer-reviewed literature, or reference to an established methodology supported this approach (at [127]-[128]). The court noted he was not provided with the HAZMAT ID graph he had requested, and no explanation was given for that omission, meaning his laboratory work drew on only a single technique (at [124]-[125]).

Dr Coghlan himself acknowledged that he expressed only a "reasonable" level of certainty regarding his opinion, distinctly lower than the "very high certainty" he associated with proper confirmatory laboratory testing (at [55]-[56]). Professor Hibbert's unchallenged evidence was that Dr Coghlan's laboratory test did not alter the possibility of a false positive arising from the original field presumptive testing (at [130]-[131]). Both experts agreed that presumptive testing is, by definition, incapable of serving as a forensic tool and requires confirmatory laboratory analysis to reach a definitive conclusion about substance identity (at [122]-[123]).

Issue 2: Exclusion under section 137 of the Evidence Act

Even if the opinion had been admissible, the court stated it would have excluded the evidence under section 137 (at [133]-[135]). There was a real danger that a jury would misuse the opinion to reach a conclusion beyond reasonable doubt, particularly given that Dr Coghlan's own expressed certainty was only "reasonable" (at [135]). The court also found that surrounding circumstantial evidence, including conversations and written notations attributed to the accused suggesting he expected a shipment of benzyl cyanide, could inform findings about his state of mind but could not establish what substance was actually delivered (at [134]-[135]).

Orders Made

  • The opinion evidence of Dr Coghlan is inadmissible as not falling within the exception provided by section 79(1) of the Evidence Act 1995 (NSW).
  • Were the evidence found admissible under section 79(1), it would be rejected pursuant to section 137 of the Evidence Act.

Key Takeaways

  • Presumptive field testing using Raman and infrared spectroscopy instruments does not constitute a forensic identification method. The District Court confirmed that both experts agreed such testing is inherently incapable of providing a definitive conclusion and requires confirmatory laboratory analysis to do so (at [122]-[123]).

  • Under section 79(1) of the Evidence Act, an expert opinion must be wholly or substantially based on specialised knowledge, and the reasoning connecting that knowledge to the opinion expressed must be sufficiently exposed. A visual comparison between laboratory and field spectra, without supporting scientific literature or peer-reviewed methodology, did not satisfy this requirement (at [127]-[132]).

  • Where an expert's own evidence discloses only a "reasonable" level of certainty in contrast to the "very high certainty" achievable through proper confirmatory testing, that distinction is directly relevant to both admissibility and the section 137 balancing exercise (at [55]-[56], [135]).

  • Evidence of a defendant's state of mind, such as written references to a substance or conversations about an expected shipment, cannot substitute for scientific analysis of what was actually delivered when identity of a substance is in dispute (at [134]-[135]).

  • Applying Makita, Dasreef, Honeysett, and Lang v The Queen, the court reinforced that expert opinion lacking a sufficiently explained foundation in specialised knowledge risks giving an unwarranted appearance of scientific authority, particularly in criminal proceedings where the jury may give it disproportionate weight (at [81]-[94], [135]).

Legislation and Cases Referenced

Legislation
- Evidence Act 1995 (NSW)
- Criminal Code Regulations 2019 (Cth)

Cases
- Dasreef Pty Ltd v Hawchar (2011) 243 CLR 588; [2011] HCA 21
- Honeysett v The Queen [2014] HCA 29
- IMM v the Queen (2016) 257 CLR 300; [2016] HCA 14
- Lang v The Queen [2023] HCA 29
- Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR 705; [2001] NSWCA 305
- R v Bowie (No 1) [2022] NSWSC 1502
- Ramsay v Watson (1961) 108 CLR 642