A man who beat trucking company boss David Norris with a spanner at his workshop in Adelaide's northern suburbs has been found guilty of murder.
A 12-member jury took less than five hours to find Jesse Ray Penhall guilty of murder.
David Norris, 39, was found dead in a pool of blood on the floor of his Salisbury workshop in September 2017.
During the trial, the Supreme Court heard Penhall beat Mr Norris with a large spanner used for trucks, which measured 60 centimetres and weighed two kilograms.
Prosecutor Jim Pearce told the jury Mr Norris suffered multiple skull fractures, some of which were inflicted as he lay on the workshop floor.
"He was probably motionless, he was certainly unable to defend himself," Mr Pearce said.
"His battered and bloodstained body was found later that evening."
The court heard the two men were friends and had been talking amicably before the attack.
Mr Pearce told the jury the prosecution was not required to prove a motive and sometimes murders were simply senseless.
"Whatever the reason for this killing, what is clear is that something went terribly wrong inside that workshop that afternoon," he said.
Murderer admitted to throwing away bloodstained clothes
Penhall gave evidence at his trial and told the jury that Mr Norris tried to strike him first with the spanner and he was acting in self-defence.
He admitted that he stepped over the victim's motionless body after the bashing and threw away his bloodstained clothes and shoes as he fled.
The items were later found by police.
Forensic analysis matched the DNA from the blood to the victim.
Penhall stood trial charged with the shooting murder of Gypsy Joker Stephen Hydon at Wallaroo in 2004.
He and his co-accused Erin Woodward were acquitted.
Four years later Penhall nearly died when he was shot more than a dozen times during an ambush at Paskeville.
At the time police said it was not a random shooting and that Penhall could have been targeted as a consequence of his acquittal.
He has been remanded in custody to be sentenced next year.
