Three WA men jailed for 'inhumane' killing

Two men have been jailed for life over the barbaric and inhumane murder of an acquaintance who was bashed, run over and shot in the head at a Perth park after attending a gang "church night".

Alexander James Stephens and Angus William John Ritchie, both 25, were convicted of murdering 32-year-old David Liam Johnson in Swanbourne in March 2013.

Nathan Michael Beckton, 37, pleaded guilty to manslaughter and was sentenced on Tuesday to 11 years in prison.

The West Australian Supreme Court heard Mr Johnson met his killers for the first time at an Apaches gathering he attended with a friend.

After an argument with Beckton that night, Mr Johnson was stomped on, verbally abused, kicked, struck with a slab of concrete and repeatedly run over with a car.

He was then driven to Lime Kiln Field, where Stephens shot him in the head.

Justice Lindy Jenkins said Stephens had the "entirely worthless motive" of showing loyalty to his friends, describing his actions as barbaric and inhumane.

She said Stephens had a final chance to show mercy at the park, but instead shot Mr Johnson and in a final act of humiliation, left him with his pants down.

Justice Jenkins said Stephens showed some premeditation and remained a danger to the community.

She described Ritchie as Stephens' right-hand man, saying he was involved all the way, although he did not hurt Mr Johnson.

Neither man showed signs of remorse, she said.

Justice Jenkins said Mr Johnson's death had placed huge strain on his family who struggled to understand such viciousness.

Stephens was jailed for a minimum of 24 years, while Ritchie must spend at least 14 years behind bars and Beckton must serve a minimum of nine years.

Outside court, Mr Johnson's uncle, David Weir, said the family respected the judge's decision but felt that no sentence could ever be enough for the torture inflicted on Mr Johnson.

"It won't bring him back and it won't ease any of the suffering that he underwent," he said.

"They gave him a death sentence, they broke our family and they trapped us with the knowledge of what happened to him.

"Their sentence will eventually end, but David's and ours never will."

The victim's mother, Christine Johnson, said she was glad the hardest part was over.

"Now, we just pick up the pieces and keep going for the ones that are still living, that's what he'd want us to do," she said.