A yellow sheet and chewing gum found at the crime scene involving the 1989 bludgeoning death of 15-year-old Annette Mason went missing before they could be analysed for DNA, a coronial inquest has been told.
The last record relating to the sheet was in 1997 – before DNA profiling was possible in Queensland, Coroner Terry Ryan was told.
Chewing gum found on the sheet has also gone missing.
Retired forensic scientist Ken Cox, who worked on the case until he retired in 2002, told the court he received clothing, hair, nail clippings, a doona and sheets, as well as Annette's vaginal, oral and anal swabs for forensic analysis.
He said he continued to receive exhibits related to the case for testing and retesting over more than a decade.
"They were coming in for years," Mr Cox said.
"It's unfortunate. I couldn't find anything at all that was associated with pinning any individual. It doesn't always happen."
Annette was found bludgeoned to death underneath a doona in the bedroom of a house she shared with two others in Toowoomba, west of Brisbane.
A 1991 inquest found insufficient evidence to find anyone responsible for her death but was reopened by then attorney-general Yvette D'Ath in 2016.
Hearings recommenced in 2018 but were put on hold again to allow for more forensic testing.
'The first I've heard of it'
Mr Cox told the court today he was unaware the yellow sheet involved in the case had gone missing.
"It's the first I've heard of it," he said, adding he was also unaware of what had happened to the chewing gum.
Mr Cox told the inquest under questioning from counsel for the Mason family, Clem van der Weegen, an anal swab related to the case had been discarded in 1991 after he unsuccessfully tested it for sperm.
Later, Queensland Health forensic scientist Adrian Pippia, who re-analysed exhibits involved in the case using the latest available technology, told the court the swab could have "potentially" been used to test for DNA in skin cells that may have been left behind after penetration.
Mr Pippia told the court that where DNA profiles were able to be obtained, "some matches" were made, but Mr Ryan has issued a non-publication order in relation to the details.
He said the sheet and chewing gum could have also been tested for DNA, had they not been lost.
Members of Annette's family have attended this week's inquest dressed in yellow, her favourite colour.
The inquest, which resumed this week after being on hold for three years, continues before Mr Ryan.
