An innocent man caught in the crossfire of a bikie gang war was shot by a "firing squad" as he attempted to flee, a court has been told.
Panel beater Jason De Ieso was killed by a shotgun blast to the head at his business in Pooraka, northern Adelaide more than a decade ago.
A South Australian Supreme Court jury has heard a group of nine men with links to the Hells Angels motorcycle gang stormed Mr De Ieso's shop in November 2012 intending to kill a different man.
But crown prosecutor Jim Pearce KC on Wednesday said the intended target left the address minutes before their arrival and the group instead murdered the 33-year-old bystander.
Musa Alzuain, who was 19 years old at the time, is alleged to have pulled the trigger, but Mr Pearce also urged the jury to find the rest of the accused guilty as they were part of a joint enterprise to kill.
As well as Alzuain, now in his 30s, his older brothers Husain Alzuain and Mohamed Alzuain have been charged with Mr De Ieso's murder, along with Daniel Mark Jalleh, Ross William Montgomery, Seywan Moradi, Kyle Lloyd Pryde and Nicholas Sianis.
All have pleaded not guilty.
The ninth man suspected of taking part in the attack has since died.
Five of the men who stormed the shop were carrying firearms, at least three of which were loaded, while another held a metal bar, Mr Pearce told the jury.
CCTV footage played before the court showed four men at the head of the group approaching the building's entrance in a line. Some of the men are holding what appear to be firearms.
"The four of them lined up like a firing squad," Mr Pearce said.
He argued ballistic evidence showed three of the four men fired their weapons with control and an intent to kill while Mr De Ieso fled for his life.
The men made a point of getting right up in the face of people in the workshop, within five or six metres; evidence they were not interested in sending a warning, the jury heard.
Mr Pearce said the accused killers were motivated by a desire to hit back at a rival member of the Finks bikie gang amid a context of escalating violence between the groups.
The jury heard incidents dated back to May 2011, including brawls, drive-by shootings and a home invasion in which the young son of a bikie was shot in the leg.
The violence culminated in the fire-bombing of the Alzuain brothers' family home the day before Mr De Ieso's death.
That provided a powerful motive for the accused to retaliate, Mr Pearce argued.
The prosecution's closing address continues.
