Queensland Police have identified two men who delivered fuel to a bikie gang who used it in the murder of defector Shane Bowden on the Gold Coast.
Detectives have no doubt the Mongols executed their former gang member as he sat in his BMW outside his Pimpama home last October.
But they are yet to identify the two men who shot him 21 times with a machine gun and a shotgun.
Last week detectives released footage of Mongols members spying on Mr Bowden and his home, and even fitting an electronic tracker to the underside of his car so they would always know where he was.
On Tuesday, they released more footage, this time of two heavy-set men with tattooed forearms loading cans of fuel into a hire car.
Police believe that fuel was later used to torch the Ford Falcon and the Holden Commodore used as getaway cars after the execution.
The men filmed loading two red cans of fuel into the hire car have been identified as associates of the Mongols, officers say.
They want to hear from anyone who knows them or anything about the car - a dark blue Kia Cerato with Queensland registration 089 YQR.
A $250,000 reward is on offer for information leading to the conviction of those directly responsible for the murder, with an indemnity from prosecution on offer for the first accomplice who comes forward.
Mr Bowden was 48 when he died in a hail of bullets.
He was initially a member of the Finks and was part of its "terror team" jailed over the Gold Coast's so-called ballroom blitz brawl in which three people were shot and two stabbed in 2006.
After his release, he defected to the Mongols but was booted out and rejoined the Finks just before he was killed.
Months before he was murdered, he'd escaped an attempt on his life in Melbourne and fled to Queensland.