Second arrest over SA bashing murder

A second man has been charged with the bashing murder of Mark Boyce in Adelaide in 2017 as detectives continue to build a case against a third suspect.

The 31-year-old was arrested over the killing on Wednesday and was expected to face Adelaide Magistrates Court either Wednesday afternoon or Thursday morning.

His arrest follows last year's conviction of Hells Angels bikie Joshua Grant, who is serving a minimum 20-year jail sentence.

Mr Boyce, 36, suffered a fatal brain injury when he was punched, kicked and stomped on outside his home at Elizabeth South, in Adelaide's north, in January 2017.

He was admitted to hospital but died from his injuries about a week later.

Sentencing Grant last year, Supreme Court Justice Tim Stanley described the attack as savage, brutal and completely unjustified.

"The utter pointlessness of his death can only accentuate the grief of those who knew and loved him," the judge said.

On Wednesday, police said two vehicles transported Mr Boyce's three assailants to and from the scene.

In September last year, one of the vehicles, a Toyota Echo was found four metres underground, cut up and burned, on a Hells Angels Motorcycle Club property.

Police allege the owner of that vehicle is the second man arrested and charged with murder.

Detectives are still searching for the other vehicle, a Toyota Rav 4.

Superintendent Des Bray said they were working to build a "comprehensive brief" in relation to the third person allegedly involved in the killing.

He said he looked forward to the day when that investigation was complete and police could take action.

"That person should take no comfort in the fact that it's been three and a half years," Supt Bray said.

"We'll take as long as necessary and we won't give up."

Supt Bray said police also wanted to speak with someone who rang with information about the killing in October 2107, and urged anyone else with information to come forward.

"If you're reluctant to help the police, don't think about us," he said.

"If you come forward and provide information you'll actually be helping the family."

When Grant was jailed, Mr Boyce's father Malcolm said the 20-year jail term "would never, ever be long enough".

"As far as I'm concerned he's bloody lucky," he said.

Fighting back tears, he remembered his son as a "character" and a "great mate", who was just in the wrong place at the wrong time.