Six years after the killing and a sensational trial lasting 85 days, Eastman was convicted and sentenced to life without parole.
He has served 17 years in jail, and this week won the right to be considered for release from prison on licence after lodging a civil action against the Australian Capital Territory Government.
Eastman's trial and subsequent appeals had been marked by eccentric and abusive outbursts.
He dismissed a series of lawyers and finally represented himself, abusing judges in a disjointed bid to prove his innocence.
Eastman, 67, has never given up.
He lodged several unsuccessful appeals, claiming he had not been mentally fit to plead at his trial, but in 2005 a major inquiry concluded that at no stage was Eastman unfit to plead. Late last year he finally won another hearing.
In August Justice Shane Marshall ordered a new inquiry into the soundness of Eastman's conviction after finding there was fresh doubt or question about his guilt.
Despite attempts by the Director of Public Prosecutions to limit the inquiry to new evidence relating to gunshot residue found in Eastman's car, Justice Marshall agreed to include 19 grounds proposed by Eastman's counsel.
These included mental health issues, the conduct of police and prosecutors during the investigation and trial, and forensic evidence.
The Canberra Times found that one of the prosecution's key scientific witnesses, Bob Barnes, had been dismissed from the Victoria Forensic Science Centre in 1993 after concerns were raised about his evidence in several cases. The Eastman jury was not told of this.
The Canberra Times also said Eastman had presented new sworn evidence claiming that a friend had borrowed the vehicle to go rabbit shooting, accounting for the gunshot residue in the boot.
This week the Australian reported that one of Australia's leading anti-mafia prosecutors, Vincenzo Macri, was convinced the Calabrian 'Ndrangheta killed Winchester.
Macri, a former deputy chief of the National Anti-Mafia Directorate in Italy, told the Australian that he based his belief largely on police sources from Operation Cerberus, a joint state-federal taskforce that targeted Italian organised crime in the early 1990s.
"I am pleased that the Australian justice system is pursuing those responsible for the murder, whose principals are certainly to be identified within the Calabrian mafia resident in Australia," he said.
The inquiry, led by retired South Australian Judge Kevin Duggan, will hand its findings to the full bench of the Supreme Court, which can uphold or quash the conviction, order a retrial, or grant a pardon.