Kym Wayne Barnes, Shane Matthew Muckray and Chad Badcock had pleaded not guilty to the murder, but the Supreme Court jury disagreed on Friday.

Mr Doelz, 27, was found dead at the base of an embankment on the side of a road in the Adelaide Hills near the small town of Kersbrook in 2012.

Prosecutor Emily Telfer told the jury Mr Doelz was repeatedly and violently assaulted, with the attack flowing from a dispute over the missing pair of designer sunglasses.

The victim had come to know his killers through his drug use.

In January 2012, he had gone to a house at suburban Pooraka with several pairs of sunglasses that he was trying to sell or swap for drugs.

Ms Telfer said it was there that one of the pairs went missing and in trying to find them, Mr Doelz angered Barnes and Badcock.

She said about a week later they asked him to return to the house where they accused him of stealing and assaulted him, first punching and elbowing him to the head before placing a cord around his neck.

Mr Doelz lapsed in and out of consciousness during the attack.

The court heard the two men, who had been joined at the house by Muckray, put Mr Doelz in the boot of a car and drove towards Kersbrook, about 40 minutes from the city.

During the journey they continued to assault the victim, inflicting the stab wounds, including one which penetrated his carotid artery.

Ms Telfer said at one stage Mr Doelz managed to get out of the car but his escape was thwarted by a barbed wire fence not far from the side of the road.

She said on their return journey to Adelaide, Barnes and Badcock began "boasting" and "big noting" themselves about the assault.

"Statements such as 'I got him here, I got him there, I got him in the back of the neck or I got him in the head, that mean's he's f****d'," Ms Telfer said.

The body of Mr Doelz was found two days later by a man out walking.

The men will be in court for sentence submissions in February.