Cameron Ashcroft, 23, and Todd Elphick, 26, are on trial in the ACT Supreme Court for conspiring to inflict grievous bodily harm on Brendan Scott Welsh in May 2010.

Mr Welsh, 28, was ambushed and fatally shot by Kai Yuen, 28, as he sat in his car behind the Hughes shops. The killing arose from a dispute between Yuen and Mr Welsh over a car, which intensified after the window of Yuen's work van was smashed.

Mr Elphick and Mr Ashcroft are accused of conspiring with Yuen to seriously harm, but not murder, Mr Welsh. Mr Elphick allegedly drove Yuen and others around the city for more than three hours trying to confront Mr Welsh, while Mr Ashcroft is accused of luring the victim to the shops.

But Yuen, who gave evidence on Tuesday, said the men were completely innocent of any involvement in his crime. He said he was in a ''foul mood'' due to the damage to his work van, and intimidated the pair into doing as he wished. ''I am a hard person to handle when I'm angry,'' Yuen told the court.

But Crown prosecutor Shane Drumgold accused Yuen of ''juicing up'' his story to make sure the men were not convicted for their role in the alleged conspiracy. Yuen allegedly told the pair they needed to exaggerate part of the story to make him look like a ''psychopath''.

But Yuen maintained that Elphick and Ashcroft did nothing wrong. ''They were all innocent and I wanted to make sure they didn't go to jail for something stupid I did.''

The trial continues.