A Perth man who was in the grips of a "calamitous eruption" of psychosis when he repeatedly stabbed his wife has been acquitted of her murder on grounds of insanity.
Upendra Pathmasri Ihalahewa, 46, was experiencing paranoid schizophrenia and not taking his medication when he attacked Darshika Nilmini Kudaligama Withana with a large kitchen knife at their Balga home in February last year.
Ihalahewa admitted to killing his wife but argued he was not criminally responsible because he was of unsound mind.
In the Supreme Court of Western Australia on Thursday, Justice Bruno Fianacca said he was satisfied Ihalahewa "became overwhelmed" with his psychotic symptoms and had not been able to appreciate the wrongness of his actions.
Ihalahewa will be indefinitely detained in a secure psychiatric facility.
The court heard Ms Withana had tried to soothe her husband by rubbing oil into his hair shortly before he launched the "brutal and persistent" attack.
"Tragically, the deceased lost her life while trying to help the accused whose mental illness had not been adequately managed on part because of his failure to take his medication, resulting in a calamitous eruption of his psychosis into violent and fatal acts," Justice Fianacca said.
"Sadly, it is not the first case of its kind."
The court heard during the judge-alone trial that the marriage had been unhappy, partly because of Ihalahewa's sexual preference for men.
But Ms Withana continued to care for her husband, whose mental health further deteriorated in the days leading up to her death.
Justice Fianacca accepted Ihalahewa was "acutely psychotic" at the time of the attack and believed his wife was "plotting with her friends to kill him".
He added there was no evidence Ihalahewa had behaved violently towards Ms Withana or anyone else in the past.
The judge said Ihalahewa had suffered psychotic symptoms for some time which he dealt with by seeking to avoid contact with his wife.
Rather than appreciating her efforts to care for him, he incorporated her into his delusional paranoia, perceiving her as being complicit in his "tormenting auditory and visual hallucinations".
Ihalahewa will remain securely detained until the governor orders his release.
Australian Associated Press