Convicted murderer Bandali Debs has rejected accusations his evidence against alleged police killer Jason Roberts is designed to minimise his own involvement in "low and callous acts".
Roberts, 41, has pleaded not guilty to the murders of Sergeant Gary Silk and Senior Constable Rodney Miller at Moorabbin, in Melbourne's southeast, on August 16, 1998.
A jury was told both Debs and Roberts were convicted for the killings 20 years ago, but Roberts' conviction was overturned and he is now facing a re-trial.
It also heard that Roberts carried out 10 armed robberies with Debs, but was not in Moorabbin at the time of the shootings.
However Debs, who is testifying from Goulburn Prison, told the jury Roberts was with him in a blue Hyundai hatchback when Sgt Silk and Sen Const Miller pulled them over.
When Sen Const Miller approached him carrying a gun and a torch he was afraid for his safety and shot the policeman from under his arm through his cardigan, Debs said.
He claimed he did not shoot Sgt Silk himself, but rather heard shots fired from where the officer was standing with Roberts some distance away.
Justice Stephen Kaye told the jury that some aspects of Debs' evidence did not support the crown case and he had given leave to the prosecution to test these via cross-examination.
During that questioning by Ben Ihle QC, Debs rejected allegations he had actually shot Sgt Miller through the window of the Hyundai, "the gunfire equivalent of a sucker punch", when Sgt Miller would not have been able to see what was happening.
He also disagreed that he shot Sgt Miller two more times after he had already fallen on the ground.
"I suggest the account you gave this jury is one where you have sought to minimise and distance yourself from these particularly low and callous acts," Mr Ihle said.
"No it is not," Debs replied.
He testified he gave Roberts a second gun before the shooting that was loaded with two different types of bullets, but denied knowing this aligned with ballistics evidence despite having sat through his own trial for the murders.
Debs has also been sentenced for the murders of two women he shot in the head at close range, Kristy Harty and Donna Hicks.
Under defence cross-examination he testified he had no idea if he was still at risk of prosecution for other crimes including the shooting of a newsagent who was left paralysed, or for a string of other armed robberies.
After repeated questions he conceded he had asked Victorian homicide detectives to secure a parole date, provide immunity from further prosecution, and organise his return to Melbourne, as a condition of giving evidence against Roberts.
"You're comfortable telling lies to court when it suits you, aren't you?" defence counsel David Hallowes SC asked him.
"All this has been twisted," he replied.
Prosecutors allege Roberts fired one of the fatal shots that struck Sgt Silk, and it's alleged he either aided and abetted or was in a joint criminal enterprise with Debs to murder Sen Const Miller.
The Supreme Court trial before Justice Stephen Kaye and a jury of 14 continues on Friday.
