THE practices of Western Australia’s state-run pathology laboratory remain under the microscope at the Claremont serial killings trial, as the defence team continues to point to the possibility of evidence being contaminated.
Ex-Telstra technician Bradley Robert Edwards, 51, denies murdering Sarah Spiers, 18, Jane Rimmer, 23, and Ciara Glennon, 27, in 1996 and 1997, but admits abducting a teenager then raping her in a cemetery in 1995.
The crucial physical evidence in the case is DNA scraped from Ms Glennon’s fingernails, which matches DNA found on the rape victim.
Edwards admits it is his, but says he doesn’t know how it got on Ms Glennon, with his lawyers suggesting there may have been contamination in the laboratory.
They have even asked about visiting tradesmen and cited three exhibits in the case that were shown to be contaminated by PathWest scientists – with one of them not touching the evidence, just standing nearby.
A fourth exhibit labelled RH21, which was taken from vegetation on Ms Rimmer’s body, yielded a partial profile that matched the victim of an unrelated crime whose samples were processed in the same lab.
PathWest forensic scientist Aleksander Bagdonavicius was cross-examined about the vegetation on Monday, saying it took at least one week to examine and he took care not to touch any of it.
Mr Bagdonavicius said the PathWest team asked for female police officers to assist with the examination to reduce the risk of male contamination, as it was assumed Ms Rimmer had been sexually assaulted.
She was found naked but was so decomposed after 55 days in bushland it cannot be known.
Mr Bagdonavicius last week admitted making several mistakes in documentation, and was again asked about errors, conceding they were sometimes made with labelling exhibits.
He said notes were not thrown out even if they contained mistakes, which he tried to minimise.
He agreed PathWest was minimally staffed but said despite some pressure from police and the Director of Public Prosecutions, processes were not rushed.
The policy was “quality not quantity”, Mr Bagdonavicius told the WA Supreme Court.
All four contamination examples cited by the defence are not central to the prosecution’s case, but they argue it illustrates a “live issue”.
Prosecutors say the crucial exhibits didn’t come near each other, both in time and place.