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Supreme Court 25 February 2000

R v DIAZ

[2000] NSWSC 91

Homicide
CRIMINAL LAW HOMICIDE

Citation: R v Diaz [2000] NSWSC 91
Court: Supreme Court of New South Wales (Common Law Division)
Date: 25 February 2000
Judge: Barr J

Background

The accused was a 46-year-old woman charged with the murder of her seven-year-old son at their home in Hamilton, New South Wales, on 26 May 1999. Her husband discovered her at the scene in a severely disturbed state. She was subsequently admitted to hospital as an involuntary patient.

The accused had a documented history of serious mental illness dating back to the birth of her first child in 1992, when she developed a psychotic condition initially described as post-natal depression. She experienced a further episode following the death of her second child in 1995. In the days leading up to the events of 26 May 1999, she was under active psychiatric care and had been assessed at home by her case manager and a treating doctor on the very day of the killing.

The trial proceeded before Barr J sitting alone, following the accused's election for trial by judge alone. Both the Crown and defence accepted that the accused lacked criminal responsibility for her actions by reason of mental illness, and both counsel submitted that a special verdict of not guilty on the ground of mental illness was the appropriate outcome.

  • Whether the accused had sufficient mental capacity to elect trial by judge alone, notwithstanding questions about her mental state at the time of the offence
  • Whether the accused had established, on the balance of probabilities, that at the time of the killing she was suffering from a disease of the mind that deprived her of the capacity to know that what she was doing was wrong (or, alternatively, to know the nature of her act)
  • Whether a special verdict of not guilty on the ground of mental illness should be returned

Decision

Barr J accepted evidence from two forensic psychiatrists, Dr Westmore (retained by the defence) and Dr Strum (retained by the Crown). Both were in full agreement in their diagnoses and conclusions. The court found that the accused was suffering from paranoid schizophrenia at the time of the killing, characterised by persecutory delusions, erotomanic beliefs, possible auditory hallucinations or thought insertion, and features consistent with Capgras syndrome. Capgras syndrome is a rare psychiatric condition in which a person believes that someone close to them has been replaced by an identical replica. In this case, the accused appeared to hold the belief that her son was a dummy rather than a living child.

The central legal question was whether the accused's illness deprived her of the capacity to know that her actions were wrong. Both psychiatrists concluded that, while she likely understood the physical nature of her actions, her psychotic state entirely removed her ability to appreciate that what she was doing was wrong. The Crown prosecutor accepted that the evidence established this on the balance of probabilities, a concession Barr J described as a proper one.

Barr J concluded that a special verdict of not guilty on the ground of mental illness was the only verdict to which the court could properly come. He described the case as "truly tragic," noting that the accused had no criminal tendencies and no control over her illness. He expressed the court's sympathy for the accused and her relatives.

Pursuant to the applicable statute, the court was required to order the accused's detention until released by due process of law. Barr J noted that in practice this would mean referral to the Mental Health Review Tribunal under the Mental Health Act 1990, which would review her case and make periodic recommendations to the relevant Minister regarding her detention, care, and treatment, having regard to both public safety and the accused's own ongoing needs.

Orders Made

  • The accused is not guilty of the charge of murder by reason of mental illness.
  • The accused is to be detained in a hospital until released by due process of law.

Key Takeaways

  • A special verdict of not guilty on the ground of mental illness requires the accused to prove, on the balance of probabilities, that a disease of the mind either deprived her of the capacity to know the nature of her act or deprived her of the capacity to know that the act was wrong.
  • Where both the Crown and defence psychiatric experts agree that the accused lacked the capacity to know her actions were wrong, the court confirmed that a special verdict is the only proper outcome on those facts.
  • A finding that an accused likely understood the physical nature of her actions does not preclude a special verdict; incapacity to appreciate the wrongness of the conduct is a separately sufficient basis.
  • Following a special verdict, the court is required by statute to order detention until released by due process of law, with the Mental Health Review Tribunal conducting periodic reviews and making recommendations to the Minister regarding the accused's detention, care, treatment, and the safety of the public.
  • The accused's documented history of recurring psychotic illness, combined with active psychiatric monitoring in the days immediately before the offence, formed a significant part of the factual foundation for the medical and legal conclusions reached.

Legislation and Cases Referenced

Legislation:
- Mental Health Act 1990 (NSW) (governing the Mental Health Review Tribunal process following a special verdict)
- The applicable criminal statute governing special verdicts and mandatory detention orders (referenced in the judgment but not named explicitly)

Cases cited: No cases were cited in the judgment.