AI-generated summaries. Not legal advice. Always verify against the official judgment on NSW Caselaw.
← All decisions
Supreme Court 17 September 2026

R v XK

[2026] NSWSC 1129

Homicide
CRIME MURDER DEFENCE OF MENTAL HEALTH IMPAIRMENT

Citation: R v XK [2026] NSWSC 1129
Court: Supreme Court of New South Wales
Date: 17 September 2026
Judge(s): Cavanagh J

Background

The accused was charged with the murder of her two children, aged 11 and 9, who were stabbed to death on the night of 9 or 10 September 2024. Following the killings, the accused attempted to take her own life by making numerous lacerations to her body, including cuts to her wrist, arm and neck. She was discovered by the children's father the following afternoon, semi-conscious in a bathtub.

The accused entered pleas of not guilty to both charges of murder, relying on the defence of mental health impairment under the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW). Both the Crown and the accused proceeded by way of a joint application under section 31 of that Act, asking the Court to enter a special verdict that the acts were proven but that the accused was not criminally responsible.

Names and identifying details were anonymised at the request of the children's father, in accordance with section 15A of the Children (Criminal Proceedings) Act 1987 (NSW).

Legal Issues

  • Whether the evidence established the defence of mental health impairment under section 28 of the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW), such that the Court could be satisfied a special verdict should be entered pursuant to section 31.
  • Specifically, whether the accused, at the time of the killings, did not know that her acts were wrong, within the meaning of section 28(1)(b) of the Act.
  • What orders should follow upon entry of a special verdict, including the terms of the accused's ongoing detention and referral to the Mental Health Review Tribunal.

Decision

The joint application and the Court's independent role

Although both the Crown and the accused jointly sought the special verdict, Cavanagh J emphasised that agreement between the parties is a prerequisite to a section 31 hearing but does not of itself compel the verdict. The Court retained an independent obligation to scrutinise the evidence and reach its own state of satisfaction before entering the special verdict. Cavanagh J noted that the community has an interest in understanding that any decision to hold an accused not criminally responsible is properly made and capable of withstanding close scrutiny (at [16], [21]).

Whether the defence under section 28 was established

The parties agreed that the accused knew the nature and quality of her acts. The sole operative limb of the defence was therefore section 28(1)(b): whether she did not know that her acts were wrong (at [14]-[15]). Cavanagh J accepted that this is a question of fact for the Court, informed by but not simply delegated to expert psychiatric opinion (at [41], [90]).

Three independent expert psychiatrists, Dr Ellis (retained by the accused), Dr Nielssen (retained by the accused) and Dr Martin (retained by the Crown), each diagnosed the accused with major depressive disorder, with Dr Nielssen characterising it as major depressive illness with melancholic features. All three were unanimous in their opinion that, at the time of the killings, the accused did not know her actions were wrong because she could not reason with a moderate degree of sense and composure as to whether those acts, as perceived by reasonable people, were wrong (at [91]).

Cavanagh J was satisfied by the concurrent oral evidence given at the third hearing that the accused's major depressive disorder was of such severity that her thought processes were psychotic in character. Her nihilistic thinking led her to believe that her children would be better off dead in what she perceived as a hopelessly bad world (at [87]-[88]). The expert evidence also addressed the significance of the accused's extensive pre-offence internet searches and apparent planning. All three psychiatrists considered that this conduct did not undermine the defence; rather, it reflected the pervasive nature of the accused's disordered thinking (at [89]).

Orders following the special verdict

Having entered the special verdict, Cavanagh J ordered the accused's detention at a location to be determined by the Mental Health Review Tribunal, to which she was also referred. The accused became a forensic patient subject to ongoing Tribunal supervision, review and treatment. She may not be released until the Tribunal is satisfied that neither her own safety nor the safety of any member of the public would be seriously endangered by her release, and until the Attorney General and Minister for Health have had the opportunity to be heard (at [92]-[93]).

Orders Made

  • Special verdict entered on each charge: the act is proven but the accused is not criminally responsible (pursuant to section 31 of the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW)).
  • The accused is to be detained at a location determined by the Mental Health Review Tribunal until released by due process of law (pursuant to section 33(1)(b) of the Act).
  • The accused is referred to the Mental Health Review Tribunal (pursuant to section 34 of the Act).
  • The Registrar is to notify the Minister for Health of the verdict and orders as soon as reasonably practicable.
  • The Registrar is to notify the Mental Health Review Tribunal of the verdict and orders as soon as reasonably practicable, and provide copies of the reasons, agreed facts and expert reports.
  • The Registrar is to notify the Justice Health and Forensic Mental Health Network of the verdict and orders as soon as reasonably practicable, and provide copies of the same documentation.

Key Takeaways

  • Under section 31 of the Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW), a joint application by the Crown and the accused is a prerequisite but is not sufficient on its own to secure a special verdict. The court must independently consider the evidence and reach its own state of satisfaction that the defence is established before the verdict can be entered (at [7], [16]).

  • Section 28 of the Act operates disjunctively: it is sufficient that a mental health impairment caused the accused either not to know the nature and quality of the act or not to know that the act was wrong. Both limbs need not be established (at [13]).

  • Major depressive disorder can constitute a mental health impairment for the purposes of section 28, and where its severity reaches a psychotic level, it may deprive a person of the capacity to reason with a moderate degree of sense and composure about whether their conduct would be perceived as wrong by reasonable people (at [87]-[88]).

  • Pre-offence internet searches and apparent planning by an accused do not necessarily defeat a mental health impairment defence. In this case, the Supreme Court accepted expert evidence that such conduct reflected the pervasive nature of the accused's disordered thinking rather than purposive rational conduct inconsistent with the defence (at [89]).

  • A person for whom a special verdict of act proven but not criminally responsible is entered becomes a forensic patient. Release requires the Mental Health Review Tribunal to be satisfied that neither the person's safety nor the safety of any member of the public would be seriously endangered, and the Attorney General and Minister for Health must be given the opportunity to be heard before any release (at [93]).

Legislation and Cases Referenced

Legislation
- Crimes Act 1900 (NSW) , s 18
- Mental Health and Cognitive Impairment Forensic Provisions Act 2020 (NSW) , ss 4, 27, 28, 31, 33, 34

Cases
- Da-Pra v R; R v Da-Pra [2014] NSWCCA 211