Joshua Roy Grant is standing trial charged with murdering Mark Boyce at Elizabeth South

Mark Boyce was killed in a brutal group attack lasting 20 seconds, a Supreme Court jury was told on Thursday. One of the men is standing trial charged with Mr Boyce’s murder.

A murder victim who was ambushed and brutally assaulted by three men on a suburban street was “in the wrong place at the wrong time”, a Supreme Court jury has heard.

Mark Boyce stepped outside his Hill St, Elizabeth South, home about 10.40pm on January 30, 2017, to ask a man waiting outside for a lift, when another man got out of a car and chased him down the street.

He was caught before that man and two others began “kicking, punching and stomping” on him in an attack lasting 20 seconds.

Only one of those three men, Joshua Roy Grant, is standing trial charged with Mr Boyce’s murder.

Mr Boyce suffered multiple injuries including a blunt force head injury which resulted in swelling on his brain.

He died just over a week later in the Royal Adelaide Hospital on February 8, 2017, after his life support was turned off.

Opening the trial before a jury of eight women and four men on Thursday, prosecutor Emily Telfer SC, said Mr Boyce was “brutally assaulted”.

She said the three men allegedly involved were searching for a different man — their intended target — who was “hiding out” at Mr Boyce’s house.

Murder victim Mark Boyce was bashed outside his home at Elizabeth South on January 30, 2017. Picture: SA Police

That intended target had also sought a lift from the man waiting outside, but fled and hid on the roof once he saw two cars approach.

One of the three men then got out of an approaching car and asked Mr Boyce where their intended target was before chasing him down the street.

“He tried to run from the men but he was caught and he was brought to the ground,” Ms Telfer said.

She said then the three men then began “kicking, punching and stomping on him” causing Mr Boyce’s fatal brain injury.

Ms Telfer said the events leading to the assault were “no spur of the moment dispute that got out of hand”.

“Rather it is alleged the assault on Mr Boyce followed from a deliberately planned and carefully executed ambush,” she said.

“The three men who committed the assault deliberately placed themselves in Hill St after 10pm on the 30th of January because they were looking for (their intended target).

“Mr Boyce was in the wrong place at the wrong time.

She said the “combined assault by the group was as brutal as it was swift … Mr Boyce was left on the footpath unconscious.”

“From the moment that Mr Boyce was chased and brought to the ground to the moment his attackers got back in the car was no more than 20 seconds,” she said.

Ms Telfer told the jury they should not speculate why only Grant was standing trial, instead of all three men involved in the attack.

The trial, before Justice Stanley, is expected to continue for two weeks.