Fatal stabbing was ‘one in several million’ event that could not have been prevented,Coroner finds

The unprovoked stabbing of a much-loved teacher in Sydney’s inner west was an extremely rare outburst of homicidal violence from a man receiving close treatment for a mental illness,a coroner has found.

Brian Liston,51,had attended a German lesson on the evening of December 10,2015 and was waiting for a bus on Salisbury Road in Camperdown when he was confronted by William Cahill,34,who lived in a unit across the road.

Brian Liston was killed in a stabbing at a Camperdown bus stop in December 2015.

Brian Liston was killed in a stabbing at a Camperdown bus stop in December 2015.Supplied

Cahill,who had a history of chronic treatment-resistant schizophrenia including delusions,thought Mr Liston looked like the family member of a former housemate. He walked out to confront him and stabbed him without warning at about 8.30pm.

Multiple passersby attempted to intervene,including a man who kicked Cahill in the back,but Mr Liston died from a stab wound to the heart. Cahill was later found not guilty of murder due to mental illness.

In findings on Thursday,Deputy State Coroner Elizabeth Ryan said Cahill was taking medication and had been provided a high level of care and support from a community mental health team in the lead-up to the tragedy.

Several hours before the stabbing,Cahill had spoken to a member of the mental health team and nothing about his behaviour suggested he was unwell.

Ryan said there was no deficiency in the “competent and caring” support provided to Cahill,and no sign that his mental state would suddenly deteriorate. She declined to make any recommendations in the case.

Two forensic psychiatrists told the inquest that such an unpredictable outburst of violence was extremely rare,particularly from a person receiving treatment.

Associate Professor Matthew Large said in his evidence that stranger homicides by people with psychosis or schizophrenia are “one of the rarest adverse events associated with severe mental illness”. For those receiving treatment,he said,such a homicide is so rare it is in the order of one in several million.

Ryan said it may have been a comfort to Mr Liston’s family “to learn how rare such tragic episodes are”.

“But it must also have been heartbreaking to know that Brian,their beloved husband,father and brother,was that one in several million,” she said.

The coroner said evidence at the inquest appeared to highlight a gap in the support available to people like Cahill,who require intensive support in the community but are not so acutely unwell they need to be involuntarily detained.

One psychiatrist told the inquest there was a need for more placements for people in the same situation;a concern shared by members of Mr Liston’s family.

“It is beyond the scope of this inquest to make any recommendations directed to this issue,” Ryan said. “However,it is a matter which deserves serious consideration within the community,and amongst health care services and those who provide their funding.”

The inquest heard Mr Liston had a large and loving family and a group of devoted friends,enjoying hobbies including writing poetry,playing music and coaching cricket. Ryan said his death was “shocking and profoundly sad”.

“He was deeply loved and is deeply missed by his family and many friends,” she said. “I hope that this inquest has helped to resolve questions and concerns that may have been adding to their distress over his loss.”

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clarification

An earlier version of this story quoted expert evidence that the incidence of stranger homicides by people with psychosis or schizophrenia is so rare it is in the order of one in several million. The story has been amended to clarify that this statistic is in reference to those receiving treatment for their illness.

Georgina Mitchell is a court reporter for The Sydney Morning Herald.

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