The president of a Nazi-affiliated white nationalist group, accused of being part of a "death squad" which killed a man in his own bed, has told a court one of his young followers was the lone attacker - and that he was too "weak" to stop the fatal beating.

Robert Edhouse, 22, is on trial with his lover Melony Attwood, 36, and young acolyte Corey Dymock, 21, who stand accused of jointly murdering Alan Taylor at his Girrawheen home in 2016.

A fourth attacker, a teenager whose name has been suppressed, has previously pleaded guilty of his part in the killing - and it was him that Mr Edhouse said carried out the beating on his own because he was upset that he was going to be thrown out of Mr Taylor's house, where the group had been living.

Giving evidence at WA’s Supreme Court today, Mr Edhouse said the man had entered the bedroom on two separate occasions and had "looped out" on Mr Taylor, using a hammer and then knuckledusters to inflict the beating which him with massive head wounds and brain injuries.

Mr Edhouse said the "animal-like" attack left him rattled, stunned and unable to stop it.

Camera Icon Forensic police at the Girrawheen house. Credit: File.

“He (Alan) didn’t deserve it the first time – let alone the second,” Mr Edhouse said.

“But I was too much of a soft c..., too weak, to do anything. I was frozen, in disbelief.”

Mr Edhouse claimed that after the beating, he had urged the teenager and the others to call an ambulance or the police.

But he said that the youngster insisted: “I’m not calling the cops, I don’t want to go to jail”.

The group instead brainstormed what they were going to do to avoid detection.

That included an idea to burn down the house to make it look as if Mr Taylor had died in a fire, or make it look like a “run through” or a break-in at the house.

The jury has been told that was what happened. The house was crudely ransacked before the group went to a nearby cinema and watched “The Jungle Book” to create an alibi.

Prosecutors allege that it was in fact Mr Edhouse and Ms Attwood, who had begun a sexual relationship while living at Mr Taylor’s house, who drove the murder plot after becoming “tired” of the FIFO worker.

According to prosecutor Justin Whalley, Mr Edhouse was the president of the Perth chapter of the white nationalist group Aryan Nations, while Mr Dymock was the sergeant-at-arms. Ms Attwood was said to be the leader of the female branch of Aryan Nations, called Aryan Girls.

It is alleged that after Ms Attwood dropped her three-year old son at daycare, she and Mr Edhouse collected Mr Dymock and the other male from a Maylands apartment in her car, and then returned to Girrawheen.

“Forty two minutes is all it took from the time this death squad arrived at the house until the time they left … to execute their plan to kill Alan Taylor who was bludgeoned to death with a hammer,” Mr Whalley said in his opening address.

After the movie, they then returned to Mr Dymock’s apartment, where they are alleged to have laughed and joked about the killing, while Ms Atwood also spoke of how she was now in line to collect a life insurance policy she believed to be worth $1 million.

Later that day, Ms Attwood is accused of going through the “charade” of a 000 call, after which emergency services attended the house.

The court was told ambulance officers waited for police, because of warnings on their system about the address previously being adorned with swastikas and Nazi regalia.

When they did eventually get inside they found Mr Taylor dead and covered in blood – with doctors later finding he may been alive for up to five hours after his beating.

All three deny the charge of murder. The trial continues.