A retrial of the David Eastman murder case could be riddled with problems, according to a former attorney-general of the ACT.
Eastman's conviction for the 1989 murder of Australian Federal Police assistant commissioner Colin Winchester was quashed on Friday.
Eastman was released on bail pending a retrial, after agreeing to strict conditions imposed by the ACT Director of Public Prosecutions (DPP).
On Friday night Eastman spent his first night outside prison since his trial and conviction in 1995.
In its decision, the court said the circumstances of the offence weighed heavily in favour of ordering a retrial.
"If we do not order a retrial, Mr Eastman's guilt or otherwise will never be determined," the court said.
"Whilst Mr Eastman would of course be entitled to the presumption of innocence, in our opinion it is not in the interests of justice for the controversy as to his alleged role in the murder to be left unresolved when there remains a strong circumstantial case against him."
The ACT DPP said he was still considering whether to run a new trial.'This is going to be very problematic'
Gary Humphries was the ACT attorney-general when Eastman was originally tried and convicted.
He has warned the passage of time would make it hard to rely on potential witnesses.
"There are still other people who need to be brought forward to recall what they saw or knew about the case at the time," Mr Humphries said.
He also pointed out that much of the forensic evidence had been discredited.
"This is going to be very problematic as a legal proposition, we are looking at a crime that was committed some 25 years ago."
There are doubts about whether a retrial could secure a conviction at all.
"There'll be obviously the risk of an application by Eastman's lawyers to suggest that any proceedings at this very, very late juncture would be unsafe, and any conviction secured in these circumstances would be too unsafe to stand," Mr Humphries said.Long fight against conviction
Mr Winchester was shot as he got out of his car in his neighbour's driveway at Deakin on January 10, 1989.
Eastman became a suspect in the case the day after the killing.
Detectives targeted Eastman, who had threatened Mr Winchester after he refused to help him have an assault charge withdrawn.
Eastman believed if he was convicted for that crime, it would thwart his bid to rejoin the public service.
He was eventually convicted of killing Mr Winchester in 1995 and sentenced to life in jail.
He has long protested his innocence, through numerous appeals including in the High Court.