WA man found guilty of murdering mate with machete and knife

A man has been found guilty of murder over a gruesome machete attack on a friend that lasted half an hour.

Gregory Quartermaine was found guilty after a trial in the WA Supreme Court and will be sentenced next year. Picture: Ross Swanborough

A drug-affected man who admitted killing a family friend with a machete and claimed the devil made him do it has been found guilty of murder.

Gregory Quartermaine had consumed methylamphetamine and cannabis when he violently attacked Wilfred Williams at a home in Tambellup, in WA’s Great Southern region, in August last year.

As others in the house fled, including children, Quartermaine attacked Mr Williams for about half an hour with a machete and knife, the WA Supreme Court heard.

Nobody saw the full extent of the gruesome attack, but Mr Williams suffered “numerous injuries” including decapitation, severing of the left hand and deep cuts to both ankles.

NCA NewsWire has chosen not to reveal other graphic details about Mr Williams’ death.

Quartermaine admitted unlawfully killing Mr Williams but argued during his trial that he was not guilty of murder because his drug intoxication impaired his ability to form an intent.

Justice Stephen Hall presided over the trial without a jury.

Justice Stephen Hall, who presided over the trial without a jury, delivered his guilty verdict on Friday and described the attack as savage.

“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 in his judgment.

One of the children at the home heard Quartermaine say: “I’m going to kill Pop Willy.”

In his police interview, Quartermaine said he did not recall what he had done.

He also referred to a “black magic man having jumped into Uncle Willy” and said “the devil had made him” attack Mr Williams because he was hiding something in his room.

Quartermaine will be sentenced next year.