MURDER accused Anthony Charles Oliver is poised to tell a court he believed 100% that his mate was about to set him on fire when he shot him in the head at the Somerset Dam.
Barrister Michael Byrne told Brisbane Supreme Court that his client had admitted he was having an affair with Norman Cheney's wife Trichelle.
He said Mr Oliver, who is about to step in the witness box, would say they had been fighting, that Mr Cheney had choked him to the point of passing out twice.
Mr Byrne said Mr Oliver woke to find petrol had been poured all over him and he saw a lighter.
"He could hear the lighter going click click click," he said.
"He was (in) fear for his life.
"He was 100% sure he was about to be set on fire."
Mr Byrne said his client would then tell the court he spotted a .45 calibre firearm under Mr Cheney's thigh.
"He reached for the gun and fired," he said. "He didn't aim.
"He didn't have any particular intent in mind but he wanted to stop what was happening with the lighter and the petrol.
"Norm immediately stopped moving and went limp."
Mr Byrne said Mr Oliver drove to his sister's place at Esk where he would later encase Mr Cheney's body in concrete inside a 44-gallon barrel which he dumped in the Caboolture River.
He said his client considered going to police but was too scared of the bikie gangs he believed were after Mr Cheney for his drug debts.
Mr Oliver has pleaded not guilty to murder, arguing he killed Mr Cheney in self-defence.
The trial continues.