David Eastman, jailed for life for murdering Australian Federal Police assistant commissioner Colin Winchester in 1989, has had his conviction quashed.

Mr Winchester, the most senior policeman to be murdered in Australia, was shot dead at his Canberra home on the night of January 10, 1989.

The killer calmly fired two shots into the policeman’s head at close range as Mr Winchester sat in his car.

Although there was speculation it was an organised crime hit, police charged Eastman, a former Treasury official with a personality disorder and a grievance against police.

He was convicted in 1995 and sentenced to life imprisonment.

Earlier this year, an inquiry into the trial concluded there had been a miscarriage of justice and recommended Eastman, now 68, be freed.

The ACT Supreme Court quashed the conviction on Friday and said there should be a retrial.

The ACT Director of Public Prosecutions will now decide whether another trial should proceed.

The court then took a break to consider Eastman’s application for bail.

Justice Steven Rares said there had been a substantial failure at Eastman’s original trial.

However, there remained a strong circumstantial case against Eastman and a new trial would not be unfair, he said.

“The community has a vital interest in ensuring that a person against whom a strong circumstantial case for murder of a very senior police officer exists does not escape having a jury decide whether or not he is guilty of that crime,” he said.