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.
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.