Alleged murderer Gregory John William Quartermaine waits to learn fate as verdict looms in Tambellup beheading

Tambellup man Gregory John William Quartermaine will learn his fate next week when Supreme Court Justice Stephen Hall delivers his verdict on the alleged murder that rocked his home town. Mr Quartermaine, 42, is alleged to have decapitated and dismembered 60-year-old family friend Wilfred Williams at a house on Garrity Street in Tambellup about midnight on August 4, while other people — including children — were inside. Defence counsel Bruno Illari is not contesting that his client killed Mr Williams, but is arguing he should be convicted of manslaughter, not murder. In his closing statement on Tuesday at Albany Supreme Court, Mr Illari said his client could not form the intent to commit murder because he was in a state of drug-induced psychosis. He could not control his actions on August 4 and was acting under delusion, rather than intent to murder, Mr Illari told the court. “He was in another world driven by some force,” he said. According to forensic psychiatrist Dr Victoria Pascu, who gave her evidence on Friday, Mr Quartermaine was suffering from an acute methamphetamine-induced psychosis. “As a result of that, he knew what he was doing physically, but didn’t have the capacity to control his actions so he couldn’t form a specific intent and lacked reasoning to be able to act in a way consistent to normal,” Mr Illari said. However, State prosecutor David Davidson said the accused’s history of drug-induced mental health episodes — including incidents in 2015 and 2018 — showed he had the capacity to form intent to cause injury or kill in such a state. Mr Davidson said Mr Quartermaine’s level of psychosis was in dispute. Justice Stephen Hall said the previous episodes showed Mr Quartermaine could exercise choice during a drug-induced mental health episode. “The 2015 and 2018 incidents involved psychotic delusions comparable to 2019 — they involved auditory hallucinations to kill or harm others,” Justice Hall said. “On those occasions Mr Quartermaine did not act in response but admitted himself to hospital despite commands.” Mr Davidson said the accused killer was aware of the potential consequences of his drug-taking but still used meth. The State also raised the severity of Mr Williams’ injuries as analysed in a post-mortem report. “Mr Quartermaine attacked extensively with a machete and other sharp objects which shows a cognitive process,” Mr Davidson said. “Using these items was not a non-stop thrashing with a machete.” Justice Hall said the case presented a difficult question of the law. Speaking to the accused, he said: “I need to think very carefully about my decision and detailed reasons for the decision.” The trial was adjourned on Tuesday until Friday, December 11, when Justice Hall is expected to deliver his verdict in Perth via video link. HOW THE TRIAL UNFOLDED DAY ONE Horrifying details of the alleged murder are revealed for the first time. We learn the full extent of the savage attack, which included decapitation and dismemberment. DAY TWO Three children and Mr Quartermaine’s sister take the stand. One child describes the accused’s behaviour on the night of the alleged murder as “non-human”. DAY THREE Mr Quartermaine considers changing his plea as he struggles to sit through police testimony. Justice Stephen Hall says the Supreme Court is “not like a classroom, where he can put his hand up and ask to be excused”. DAY FOUR The court is shown a chilling interview with homicide detectives conducted on the night of August 4. The accused tells detectives the “devil” made him kill Mr Williams. DAY FIVE The accused’s drug habits come under scrutiny, including use of the “zombie drug” flakka. The toxicology report from August 4 shows evidence of meth and cannabis use, but not flakka. DAY SIX A forensic psychologist details Mr Quartermaine’s history of drug-induced mental health episodes featuring similar reports of hallucinations and instruction from an evil entity. DAY SEVEN The trial is adjourned after the defence and prosecution give their closing statements, with the ability for the accused to form intent to commit murder at the heart of the case.