Gregory John William Quartermaine found guilty of murder after beheading family friend in meth-fuelled rage

Tambellup man Gregory John William Quartermaine has been found guilty of murdering 60-year-old family friend Wilfred Williams in a meth-fuelled killing of “extraordinary brutality” that rocked his home town. Quartermaine, 42, decapitated and dismembered Mr Williams at a house on Garrity Street in Tambellup about midnight on August 4 last year, while other people — including children — were inside. The details of the killing, revealed during a seven-day trial at the Albany Supreme Court, are so graphic that the Advertiser has chosen to withhold some of them. After committing the murder, Quartermaine told police officers at the scene: “'I cut his head off, and I will take yours”. In a chilling police interview later that night, he told homicide detectives the devil made him do it. This morning, Justice Stephen Hall delivered his verdict from the Perth Supreme Court via video-link to Albany, finding Quartermaine guilty of murder. There were tears in the courtroom as the verdict was read out. On the first day of the trial on November 23, Quartermaine admitted to unlawfully causing the death of Mr Williams by inflicting multiple sharp forces injuries. Defence counsel Bruno Illari was arguing that his client was under the influence of methamphetamine and cannabis at the time of the killing and the effects of those drugs impaired his ability to form intent. The State's case was that Quartermaine’s intent to kill was established by his actions and statements immediately before the killing and by the nature of the victim’s injuries. In his judgment today, Justice Hall said intent was the crux of the case. He said the “extraordinary brutality” of the killing supported the conclusion that the accused was in a meth-induced psychosis, and it was unlikely he would have killed Mr Williams if he was not intoxicated. “The only issue is whether at the time of the killing he had the specific intent required for murder, that is, the intent to kill or do an injury that was likely to endanger life,” Justice Hall said in his judgment today. Mr Hall came up with eight reasons for his verdict, pointing out Quartermaine had intentionally taken the drugs that caused his psychotic state. “Notwithstanding the intoxication and the delusional beliefs it caused, the accused remained aware of what he was doing and remained capable of forming an intent to kill,” Justice Hall said. “The accused attacked the deceased with a machete and a knife inflicting numerous serious injuries that caused the death of Mr Williams, “When the accused inflicted the injuries to Mr Williams, he intended to kill him. “That intent has been proven beyond reasonable doubt and the accused must, therefore, be found guilty of murder.” Justice Hall said Section 28 of the Criminal Code stated unsoundness of mind did not absolve an offender of criminal responsibility if they had intentionally caused themselves to become intoxicated. “I accept that the accused had an irrational, delusional, belief that he had to kill the deceased,” Justice Hall said. “From his psychotic perspective the killing was not wrong, but it was deliberate and intentional. “I draw that conclusion from his actions and his statement immediately before the attack that he had to kill the deceased. “In my view the only reasonable conclusion is that the accused not only had the capacity to form an intent to kill, he did in fact have that intent.” Mr Williams was a lifelong friend of the Quartermaine family and had been living with his murderer’s mother for many years. He was known to members of the family as Uncle Willy or Pop Willy. About midnight on August 4, under the influence of meth and cannabis, the accused approached his mother’s house and asked to be let in. He walked into the house with a machete and started calling out for Mr Williams, who came out of his room. He then started striking him with the machete. One of the children who was in the house at the time heard him say “I'm going to kill Pop Willy”. Another child witnesses said she heard Quartermaine say: “Mum, I have to kill Uncle Willy”. “The accused’s words and actions were clear, unequivocal and self-evidently purposeful,” Justice Hall said in his judgment. Mr Quartermaine is due to be sentenced on March 12. HOW THE TRIAL UNFOLDED DAY ONE Horrifying details of the 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 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. 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.