The man stabbed a woman three times with a long kitchen knife at the place he was living in September 2021 after she refused to give him a cigarette.
The woman received first aid from police, but died before a helicopter arrived to take her to hospital.
When he was arrested, the man lashed out and punched a police constable unconscious.
The man, who was charged with murder and assault on a police officer, appeared before Justice Matthew Palmer in the High Court at Rotorua on Thursday.
His name is suppressed and he has been referred to in the court’s published judgement as “J”.
Justice Palmer said two expert psychiatrists, Dr Jeremy Skipworth for the Crown and Dr Peter Dean for the defendant, had assessed J.
Dean considered that J was labouring “under a disease of the mind” to the extent that he was unaware of the nature and quality of his actions, or that they were morally wrong.
Skipworth’s opinion was consistent with Dean’s.
He believed J’s psychotic beliefs grossly interfered with his ability to appreciate the moral wrongfulness of his action.
“J described believing he had thoughts in his head inserted by aliens, fearing the Illuminati, believing all women in the world had been turned into artificial intelligence, believing [the woman he stabbed] was a robot and had a contagious condition,” the judge said.
J believed people, like characters in video games, did not really die.
“He believed the TV, particularly the programme Peaky Blinders, was transmitting messages or signs to him. He had delusions and hallucinations. He heard spiritual voices taunting him.”
Peaky Blinders is a multi-series fictional drama which portrays the exploits of a violent criminal gang from Birmingham, England, in the 1920s and 1930s.
Justice Palmer said the Crown accepted the only reasonable verdict in the case was a finding of proven, but not criminally responsible on account of insanity.
“I am satisfied beyond reasonable doubt that J committed the acts which form the elements of the offences,” the judge said.
“I am also satisfied, on the basis of the reports of Dr Dean and Dr Skipworth, that when he committed those acts, J was labouring under a disease of the mind to such an extent as to render him incapable of understanding the nature and quality of his acts or knowing they were morally wrong.”
He ordered that J be detained in hospital as a special patient, to be treated in a secure unit under the oversight of Forensic Mental Health Services.