Five bikies found guilty of bashing

Five Finks bikies have been found guilty of viciously bashing a fellow senior member at the gang's Adelaide clubrooms.

Bozidar Cekic, 24, Mostyn Niemann, 27, Corey Dettmann, 42, Dean Richard Ciantar, 24, and Paul Paunovic, 39 had denied aggravated counts of theft and of causing serious harm with intent to former sergeant-of-arms Charles Bonnici.

The crown alleged that the five members of the now defunct gang bashed Mr Bonnici on February 14, 2013 at its north chapter clubrooms at Salisbury to enhance their standing in the gang.

In the SA Supreme Court on Tuesday, Chief Justice Chris Kourakis, who heard the trial without a jury, found that each of the five men participated in the joint enterprise to cause Mr Bonnici serious harm.

He found Cekic, Dettman and Paunovic were the attackers, while the other two men were the lookouts.

The theft charge related to a $67,200 gold necklace worn by Mr Bonnici, but the judge found the five men had no case to answer on that count.

Mr Bonnici, who weighed 140kg and was 175cm tall, lost a lot of blood and suffered life-threatening injuries including a collapsed lung, numerous fractures and brain swelling.

One of his toenails was ripped off.

He's been left with memory and brain functioning deficits and is likely to permanently suffer "mood and behaviour dysfunction".

"He has been left with a predisposition to physical aggression and reactiveness due to irritability and impulsivity," the judge said.

Mr Bonnici, who did not give evidence, was assaulted with pool cues, a vacuum cleaner and a table.

The judge rejected evidence from Cekic, who claimed self defence saying he was attacked first by Mr Bonnici after an argument about the five having to wait outside the club on such a hot day.

The judge also rejected evidence from Dettman who claimed he only separated Cekic and Mr Bonnici.

He found that senior members of the gang's central and south chapters were to meet with Mr Bonnici, probably because of complaints about his leadership of the north chapter.

The judge was satisfied that each of the accused agreed to inflict serious harm on Mr Bonnici.

"I find that they agreed to inflict that level of harm because they realised that it would be necessary to do so in order to subdue a man of Mr Bonnici's size.

"There could be no half measures in a planned assault on Mr Bonnici."

A sentence hearing will take place on a future date.