The finding could mean the convicted murderer is freed after almost 19 years behind bars, if it is followed by the ACT Supreme Court.

The inquiry has taken six months, thousands of pages of documents, dozens of witnesses, and countless man hours. Acting Justice Brian Martin said he was ''fairly certain'' Eastman was guilty, but ''a nagging doubt remains''.

He recommended Eastman's conviction be quashed and said a re-trial would not be feasible. The judge has also made a recommendation that Eastman be pardoned.

He found a miscarriage of justice occurred during the trial.

''As a consequence of the substantial miscarriage of justice, the applicant has been in custody for almost 19 years,'' Acting Justice Martin wrote.

Eastman, the judge said, was denied a fair chance of requital, and did not receive a fair trial.

''The issue of guilt was determined on the basis of deeply flawed forensic evidence in circumstances where the applicant was denied procedural fairness in respect of a fundamental feature of the trial process concerned with disclosure by the prosecution of all relevant material,'' Acting Justice Martin wrote.

The forensics used to link Eastman to the Deakin murder scene were almost entirely debunked during the inquiry.

The forensic expert responsible for analysis of gunshot residue, Robert Collins Barnes, repeatedly had his credibility and reliability savaged.

He conceded some of his evidence had been misleading, and the inquiry heard he had mislabelled exhibits, and destroyed some material.

Mr Barnes was also covertly recorded professing himself to be a ''police witness'', and criticising others for wanting to review his work.

The report now lies with the ACT Supreme Court, where a full bench of the court will decide on a way forward.

Eastman was convicted of the 1989 assassination of Winchester.

Winchester was shot twice at close range as he got out of his car on his neighbour's driveway.

The killing shocked the nation, and has become one of Australia's most notorious crimes. Eastman, a disgruntled and sacked public servant, quickly became a suspect and was arrested and taken to trial in 1995 following a lengthy investigation.

The Australian Federal Police lost a last-minute attempt to stave off publication of the report on Friday afternoon.