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Supreme Court 19 December 2025

R v Costa

[2025] NSWSC 1575

HomicideDomestic & family violence
CRIMINAL LAW MURDER OF AN INTIMATE PARTNER OBJECTIVE SERIOUSNESS OF OFFENDING “ UNASCERTAINED CAUSES” NO HISTORY OF DOMESTIC VIOLENCE AGGRAVATING FACTORS

Citation: R v Costa [2025] NSWSC 1575
Court: Supreme Court of New South Wales
Date: 19 December 2025
Judge: Campbell J

Background

The offender, a 28-year-old Sydney man, pleaded guilty to the murder of his intimate partner, a 32-year-old Russian national who had been living in Australia on a working visa since late 2022. The two had met in January 2023 and formed a relationship over approximately six weeks. The murder occurred around midnight on 24 to 25 February 2023 at the offender's home in Greystanes, where the deceased had been staying intermittently.

On the evening of the offence, the pair had been drinking heavily at a local hotel, where tension arose over the offender's possessiveness. During the Uber ride home, the deceased stated her intention to end the relationship. Shortly after arriving home, the offender inflicted the fatal injuries.

The offender entered a guilty plea while the matter was still in the Local Court and was committed to the Supreme Court for sentence in May 2025. A dispute arose at sentencing over the precise medical mechanism of death, which required expert forensic pathology evidence.

  • What was the objective seriousness of the offending, including the offender's mental state (intent to cause grievous bodily harm rather than to kill) and the degree of force used?
  • How should the disputed or "unascertained" medical cause of death affect the assessment of objective gravity?
  • What weight should be given to the aggravating factor of the offence occurring in the home?
  • What discount applied for the early guilty plea, and how did the offender's subjective circumstances (remorse, prior good character, rehabilitation prospects) affect the sentence?

Decision

Objective seriousness. Campbell J assessed the objective gravity of the offending as somewhat below the middle range. The offender's mental state was one of intent to inflict grievous bodily harm (serious bodily injury) rather than an intent to kill. The force applied was characterised as moderate, not extreme or severe. There was no history of domestic violence in the relationship, and the killing arose from the acute emotional distress of a very new relationship rather than a prolonged pattern of controlling behaviour. The court acknowledged the serious observations made in Munda v Western Australia about the gravity of intimate partner violence, while still reaching the conclusion that this particular offending sat below the midrange on the objective scale.

Disputed cause of death. Expert forensic pathology evidence from three pathologists was adduced regarding the mechanism of death. The court accepted that there were multiple possible contributing factors and that the precise cause was to some degree unascertained. This finding informed the assessment of objective seriousness, particularly in connection with the level of force applied.

Aggravating factors. The court treated the location of the offence as an aggravating circumstance. The murder occurred in the offender's own home, which was also a place of residence for the deceased. This engaged the statutory aggravating factor of committing an offence in the victim's home under the Crimes (Sentencing Procedure) Act 1999 (NSW).

Subjective circumstances and sentence. Campbell J gave substantial weight to the early guilty plea, genuine remorse, prior good character, and strong prospects of rehabilitation. The court noted that the offender had no prior criminal history, had behaved well in custody, and had the support of his family. A 25% statutory discount applied for the plea of guilty entered at the earliest opportunity. The pre-sentence non-parole period was not altered from the standard 75% ratio, reflecting the court's view that sufficient supervision time was needed to assist the offender's reintegration.

Orders Made

  • The offender was convicted of murder on his guilty plea.
  • Sentenced to a total term of imprisonment of 18 years (reduced from a notional 24 years by a 25% discount for the early guilty plea).
  • Non-parole period of 13 years and 6 months, commencing 25 February 2023 and expiring 24 August 2036.
  • Additional term of 4 years and 6 months, commencing after the non-parole period and expiring 24 February 2041.
  • First eligible for parole on 24 August 2036.
  • The offence directed to be recorded as a domestic violence offence on the offender's criminal record under s 12(2) of the Crimes (Domestic and Personal Violence) Act 2007 (NSW).
  • The court noted that the offence is a serious offence for the purposes of the Crimes (High Risk Offenders) Act 2006 (NSW), meaning the Attorney General retains a power to apply for the offender's continued detention or community supervision after sentence expiry.

Key Takeaways

  • A murder conviction does not require proof of intent to kill. Where the Crown establishes only an intent to cause grievous bodily harm, that mental state is relevant to placing the offending within the spectrum of objective seriousness, and may support a finding below the midrange.
  • Uncertainty about the precise medical mechanism of death, characterised here as "unascertained causes" with multiple possible contributing factors, formed part of the court's assessment of the degree of force used and overall objective gravity.
  • Under the Crimes (Sentencing Procedure) Act 1999 (NSW), committing murder in a home shared with the victim constitutes a statutory aggravating factor, applied by the court even where other objective features reduced overall seriousness.
  • A 25% discount for a guilty plea entered at the earliest opportunity remains available in murder proceedings, reducing the head sentence from 24 years to 18 years in this case.
  • The Supreme Court confirmed that the offence qualified as a serious offence under the Crimes (High Risk Offenders) Act 2006 (NSW), preserving the Attorney General's post-sentence supervisory powers regardless of the sentencing outcome.

Legislation and Cases Referenced

Legislation
- Crimes Act 1900 (NSW) s 19A (offence of murder)
- Crimes (Domestic and Personal Violence) Act 2007 (NSW) s 12 (recording of domestic violence offences)
- Crimes (High Risk Offenders) Act 2006 (NSW)
- Crimes (Sentencing Procedure) Act 1999 (NSW) ss 3A, 21, 21A, 30A, 54B, 61

Cases
- Hoare v The Queen (1989) 167 CLR 348
- Jonson v R [2016] NSWCCA 286
- Muldrock v The Queen (2011) 244 CLR 120; [2011] HCA 39
- Munda v Western Australia (2013) 249 CLR 600
- R v McNaughton (2006) 66 NSWLR 566