David Eastman loses bid to prevent retrial for alleged murder of Colin Winchester

On Thursday morning, the ACT Supreme Court threw out Eastman's attempt to permanently halt his retrial for the alleged murder of ACT police chief Colin Stanley Winchester in 1989.

Acting Justice David Ashley handed down his decision on Eastman's stay application in front of a packed court, but kept secret his reasons for doing so, saying he doesn't want to jeopardise the fairness of the retrial.

The family of Mr Winchester have welcomed the decision, saying they were hopeful it would set them on a path to closure.

They issued a short statement through Victims of Crime Commissioner John Hinchey on Thursday morning, praising the efforts of police and prosecutors, as well as the man who led the Winchester investigation, retired detective commander Richard Ninness.

"We are pleased with the decision and are hopeful that it is a step in the right direction that will ultimately bring justice and closure for our family," they said.

"We would like to thank the DPP and AFP for their ongoing dedication and professionalism. In particular to retired detective commander Ric Ninness and his team."

The assistant Australian Federal Police commissioner was shot twice in the head at close range as he got out of his car on January 10, 1989.

There were suggestions it was the work of the Calabrian mafia, or "Ndrangheta", who felt Mr Winchester had double-crossed them, and recent secret evidence appears to have strengthened such claims beyond mere speculation.

After a lengthy investigation, police charged Eastman, a public servant disgruntled about a pending assault charge and the loss of his job.

Eastman was convicted in 1995, and sentenced to life behind bars, but was eventually freed in 2014, after serving 19 years in prison.

His release came in the wake of an explosive inquiry, headed by former Northern Territory Chief Justice Brian Martin, which found serious flaws with the gunshot residue analysis used to link Eastman to the crime scene.

The inquiry found the prosecution's star forensic witness, Victorian Robert Barnes, had made fundamental errors, overstated his findings, was biased to the prosecution, and resistant to having his work peer-reviewed.

It was still unclear on Thursday whether Eastman would appeal the decision to dismiss his stay application. Those avenues are available to him, and are likely being closely considered.

For now, the decision means Eastman will face a jury for a second time.

That would mean a second mammoth trial. A recent estimate put the length at between four to six months, which is likely to come at great cost to the ACT taxpayer.

New figures show the cost of the Eastman case to the ACT Government has now climbed above $12 million since the beginning of the Martin inquiry.

This year's stay application alone cost taxpayers $486,000.

About $5.4 million has been provided to the DPP, the Justice and Community Safety Directorate, ACT Corrections and the Martin inquiry.

A further $3.3 million was given to Legal Aid, who are representing Eastman, and roughly $3.2 million went to the AFP and ACT Policing.

Legal assistance for witnesses has cost the government about $351,000.

A spokesman for Attorney-General Simon Corbell, who released the figures after questions by Fairfax Media, said any more funding requests would be assessed as normal.

"If the DPP, Legal Aid or the Courts require additional resources such as for the retrial this will be assessed by the normal process, to ensure necessary resources are available."

Eastman launched the stay application upon learning that the DPP planned to push ahead with the retrial.

He argued that the delay since the alleged crime, media coverage, the exorbitant cost associated with a retrial, and Eastman's age, time served, and mental health, all weighed against a retrial taking place.

Eastman also argued that the prosecution would be presenting a partially "new case" at any retrial, and that their evidence was not strong enough to warrant it being put to another jury.

He alleged prosecutors had engaged in misconduct at his original trial, by allegedly concealing weaknesses in their forensic case from him.

Prosecutors disputed every ground put forward by Eastman in his stay application, and have argued there is still strong circumstantial evidence against Eastman.

That evidence is alleged to suggest a motive, threats uttered by Eastman concerning Mr Winchester, access to firearms, identification, and the fact Eastman, who even the AFP have described as one of the most intelligent humans on Earth, could not explain his whereabouts when asked by police the next morning.

Much of the stay application was suppressed, and parts were heard in closed court.

Acting Justice Ashley's detailed reasons were handed to the parties, but they were given strict orders not to copy them, or provide them to anyone else, save Eastman himself, his legal representatives, and past counsel.

To the public, the judge issued a short summary providing a basic recap of events so far, and outlining the general nature of the stay application.

"It would defeat the purpose of the court's reasons being provided only to the parties if this summary was to set out the court's extensive findings of fact and analysis of principles," he wrote.

"It can be said, however, that the failure of Eastman's application does reflect the rejection, or partial rejection, as the case may be, of various matters which he raised."

The matter will return to court next month for a directions hearing.