A forensic scientist has defended his damning evidence against David Eastman as he responds to a barrage of criticism over his work since the night assistant federal police commissioner Colin Winchester was murdered.
But the judge heading the Eastman inquiry has already labelled part of Robert Barnes' explanation for storing more than 100 forensic case files at his home, including the file on Winchester's murder, as an ''extraordinary tale''.
The inquiry on Monday began hearing the much-anticipated evidence of Mr Barnes, a Victorian forensic officer whose gunshot residue analysis provided a crucial link between Eastman and the driveway where Winchester was shot dead in January 1989. The inquiry, ordered after fresh doubt was raised about Eastman's 1995 conviction, has already heard evidence raising serious questions about the reliability and veracity of Mr Barnes' work.
Mr Barnes said early in his evidence that he may have trouble recalling details, due to the length of time since the murder, and treatment he was currently receiving for malignant melanomas.
''I'm getting old your honour - it happens to all of us - but I'll try to do the best I can,'' he said.
The expert was questioned about what he did with the Winchester case file after he left the Victorian State Forensic Science Laboratory, where he conducted analysis relating to the murder.
The scientist had resigned from the laboratory in 1993 while facing
disciplinary charges, and took the Winchester case file to store at his home when he moved to another forensic organisation.
Mr Barnes stored the Winchester file with more than 100 other case files at the home, some of which were stored in his shed.
He claimed the head of the Victorian State Forensic Science Laboratory knew that he was keeping the files at his home, but admitted there would be no written record of that.
Acting Justice Brian Martin said he found that to be ''quite extraordinary''.
Mr Barnes' home was raided after issues were raised with his work in a separate case.
Police seized all of the case files and conducted a full technical audit of his work.
Mr Barnes said he believed that review was conducted to try to undermine him, after he gave evidence in the 1990s that opened up the possibility that Victorian Police fatally shot a prison escapee.
Earlier on Monday, Mr Barnes was asked about his use of methanol as a solvent during testing of some of the gunshot residue, something which complicated any further analysis of certain particles.
He was also asked about the state of the case file, and said efforts to maintain it were complicated by the ''tyranny of distance'' between his Victorian laboratory and Canberra, and tensions with Australian Federal Police forensics, who he said felt like the case had been snatched away from them.
Mr Barnes said he thought the police managed the crime scene well, and rejected claims he placed a hand on top of the Ford in which Mr Winchester was found dead.
He also denied becoming angry in front of a forensic officer in 1991 because police weren't arresting Eastman on the basis of his evidence.
Mr Barnes' evidence will continue on Tuesday.