Mum killer on the run in WA

A missing clinically insane man was granted leave from psychiatric custody less than a year after he was detained for murdering his mother.

Samuel Mark Walsh, 38, otherwise known as Enoch Samuel Wright, has not been seen since Sunday after he failed to return from an authorised leave of absence from Perth psychiatric facility Romily House.

Walsh was found not guilty in March 2007 of murdering his mother at her Kalgoorlie home two years earlier.

The court heard Walsh hit his mother with a broadsword before slitting her throat with a bread knife and burying her in the backyard with his dog.

Supreme Court Justice Geoffrey Miller ruled Walsh, a chronically paranoid schizophrenic, was not criminally responsible for his actions because he was insane and ordered his detention at a high-security psychiatric unit.

In January 2008, Walsh was recommended for release by way of leave of absence by the then-chair of the Mentally Impaired Accused Review Board, Judge Valerie French.

A leave of absence may be granted for emergency medical treatment, compassionate grounds or so a mentally-impaired accused can participate in rehabilitation programs.

Attorney-General Michael Mischin said the circumstances surrounding Walsh's failure to return were not known but there had been no reason to cancel or suspend Walsh's leave.

Walsh had been compliant with the conditions of his leave in the past, Mr Mischin said.

He said Walsh's disappearance had been dealt with in a timely and appropriate manner, and he would seek a report on the incident once Walsh had been returned to detention.

State opposition leader Mark McGowan said most people would expect someone like Walsh "would have been incarcerated or at least kept in somewhere that is secure".

"I think that is the least the public could expect," Mr McGowan said.

Police say Walsh is unpredictable and should not be approached.

He requires regular medication and is believed to not have it with him.

Walsh is described as 182cm tall, of slim build with brown hair and blue eyes.

It is not known what he is wearing.

Police believe Walsh is driving a 1998 silver Hyundai Excel hatchback with registration 1AFY124 and may be heading towards the Goldfields.

Anyone who sees Walsh or the car is asked to call police on 131 444.