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Supreme Court 9 July 2025

R v Dunbar (No 8)

[2025] NSWSC 1166

Homicide

Citation: R v Dunbar (No 8) [2025] NSWSC 1166
Court: Supreme Court of New South Wales — Common Law (Criminal)
Date: 9 July 2025
Judge(s): McNaughton J

Background

The accused, Mr Dunbar, faces a single count of murder. The Crown alleges that on 7 January 2022, at Toongabbie, he stabbed and killed the deceased, Mr Shane Naylor — a man towards whom the accused had demonstrated animosity. The central contested issue at trial is the identity of the person who stabbed the deceased: whether the Crown can prove beyond reasonable doubt that it was the accused.

A key witness in the trial is Mr Peter Henry. Mr Henry was initially treated by police as a person of interest in the murder investigation, having been involved in an altercation with the deceased around the time of his death and having subsequently left the scene and attempted to avoid police attention. The Crown relies, among other things, on statements and listening device recordings in which Mr Henry denied to his partner, Ms Tegan Grant, that he had stabbed the deceased. The Crown points to the spontaneity of those denials as significant evidence.

This ruling — one of several interlocutory applications concerning Mr Henry — concerned the accused's application to cross-examine Mr Henry about an extramarital affair (or act of infidelity) in order to undermine the reliability of his denials to Ms Grant. The accused argued the affair was relevant to assessing both the nature of the Henry–Grant relationship and Mr Henry's tendency to conceal information from his partner.

  • Whether the accused should be permitted to cross-examine Mr Henry about an alleged affair or act of infidelity with a view to undermining the reliability of his recorded denials to Ms Grant.
  • Whether such evidence should be excluded under s 135 of the Evidence Act 1995 (NSW) on the basis that its probative value is substantially outweighed by the danger of unfair prejudice, misleading the jury, or undue waste of time.
  • Whether the proposed line of questioning would be unduly humiliating to the witness, engaging s 41(1)(b) of the Evidence Act 1995 (NSW).

Decision

McNaughton J refused the accused's application to cross-examine Mr Henry about the affair or infidelity.

The accused had advanced three arguments in support of the proposed questioning. First, that the affair demonstrated Mr Henry's willingness to conceal information from Ms Grant. Second, that it showed Mr Henry had experience "managing information" provided to his partner on important matters — supplementing evidence already before the jury from other sources (Mr Henry's mother and an undercover operative). Third, that the relationship's fragility arising from the affair heightened Mr Henry's incentive to minimise his involvement in the events of 7 January 2022 when speaking with Ms Grant.

His Honour identified several difficulties with these arguments. Critically, there were no details about the duration or nature of the "affair." During oral argument, it was clarified that the relevant recordings referred to "cheating" rather than an ongoing affair, and that the conduct apparently occurred sometime in 2016 — roughly six years before the events in question. There was no information about whether it involved more than a single encounter. Further, the line of questioning had not been put to Ms Grant when she gave evidence, which would have been the appropriate course if the defence intended to rely on the infidelity as going to the fragility of the couple's relationship.

McNaughton J also noted that there was already a significant body of evidence before the jury demonstrating that the Henry–Grant relationship was "on and off again," diminishing the marginal probative value of the proposed evidence. Additionally, the Crown had submitted — and his Honour accepted — that the spontaneity of Mr Henry's denials on the listening devices was more central to the Crown's reliance on those utterances than the nature of the relationship itself. In these circumstances, his Honour concluded under s 135 of the Evidence Act that the probative value of the evidence was substantially outweighed by the danger that it might be unfairly prejudicial to the Crown, misleading to the jury (who might make an impermissible moralistic judgment about Mr Henry's character based on his infidelity), or result in an undue waste of time.

Orders Made

  • The accused's application to cross-examine Mr Henry about his affair or act of infidelity was refused.

Key Takeaways

  • The Supreme Court affirmed that section 135 discretionary exclusion remains a powerful trial management tool, holding that even where evidence has some arguable relevance, its probative value must be carefully weighed against the risks of unfair prejudice, confusion, and time-wasting, particularly where the evidence is remote in time and lacking in detail.

  • Remoteness in time was treated as a significant factor: conduct occurring approximately six years before the events in issue, with no evidence of its duration or significance, had very low probative value on the question of the witness's incentive to lie at the relevant time.

  • The failure to put the infidelity proposition to the relevant witness (Ms Grant) when she gave evidence weighed against allowing it to be raised with another witness (Mr Henry), particularly where the defence argument depended on the fragility of the relationship.

  • A distinct risk of moralistic reasoning was identified, namely the danger that a jury may treat evidence of a witness's personal failings (such as infidelity) as a basis for a generalised character judgment about reliability, rather than confining it to its proper logical use.

  • Where evidence going to a similar point was already before the jury (in this case, evidence that the relationship was "on and off again"), the Court held that additional evidence on the same theme had diminished marginal value and was more vulnerable to exclusion under section 135 as cumulative material.

Legislation and Cases Referenced

Legislation:
- Evidence Act 1995 (NSW), ss 41, 135

Cases:
- R v Dunbar (No 2) [2025] NSWSC 1160 (referred to for background facts)