David Eastman has spoken from prison to urge three judges to quash his conviction and not to "wimp out" by leaving the decision for a re-trial in the hands of prosecutors.
The full bench of the Supreme Court have now reserved judgment on Eastman's fate, after hearing final arguments from the 69-year-old's lawyers, and from the Director of Public Prosecutions.
Their much-anticipated decision could see Eastman released from prison more than 19 years after he was first jailed over the 1989 assassination of Assistant Federal Police Commissioner Colin Stanley Winchester.
An inquiry earlier this year recommended that his conviction be quashed, after the critical forensic evidence of Robert Collins Barnes was discredited.
Barrister Mark Griffin, QC, spent much of Thursday arguing the remaining case against Eastman was "weak, if not completely evaporated" without the forensic evidence which linked the former public servant to the murder scene at his 1995 trial.
Once Mr Griffin finished his submissions, Eastman spoke up via a video link from the Alexander Maconochie Centre, asking the judges to let him be heard, particularly after counsel for the Director of Public Prosecutions, Jeremy Kirk, SC, had "wind bagged" for two days straight.
The judges can, if they wish, quash Eastman's conviction but order a re-trial, a move which would effectively put the spotlight on the DPP, who would ultimately decide whether to prosecute a second time.
Eastman urged them not to consider passing the buck to the DPP.
"It is your responsibility and duty to make that decision," he said.
"It requires some intestinal fortitude, rather than to wimp out and pass it to the DPP."
He said the DPP had shown themselves untrustworthy, saying if they had properly disclosed problems with forensic expert Mr Barnes, a re-trial could have occurred in the mid-1990s.
"They cannot be trusted as far as you can spit," he said.
"I urge your honours to bite the bullet. Make your own decision, please do not transfer it to the DPP."
The DPP wants Eastman's conviction maintained and has argued that, even without the forensic evidence linking Eastman to the murder scene, there remains a strong case against Eastman.
The DPP has pointed to remaining evidence about Eastman's threats against Mr Winchester, links to the murder weapon, confessional utterances picked up through bugs in his home, and sightings of a car similar to his casing out the scene.
The prosecution also highlighted evidence of Eastman's motive for the murder and his inability to explain his whereabouts when police spoke with him the morning after.
"Many convictions have been upheld on a far weaker case than this, in our submission," Mr Kirk said.
He said an order for a re-trial would be appropriate if the judges did decide to quash the conviction.
Earlier, Mr Griffin said Mr Barnes' "shambolic" forensic work had been the backbone of the case against Eastman, saying it had permeated all other evidence.
He said the supposed strength of the forensic evidence would have significantly influenced the lay jury at Eastman's 1995 trial, and helped them gloss over doubts and problems with the evidence of other witnesses.
"It's not possible to simply surgically remove Mr Barnes and claim that the residual circumstantial evidence can stand," he said.
He said Mr Barnes' destruction of exhibits, his lack of notes, lack of testing data and lack of a case file meant Eastman could not now obtain a second opinion on the forensic science.
Justices Michael Wigney, Steven Rares and Dennis Cowdroy will hand down their judgment at a later date.