Crime scene samples from rape and murder cases that were initially judged by Queensland Health scientists as "insufficient for further processing" were later linked to alleged offenders after they were resubmitted by police for further analysis.
A murder late last year was allegedly solved after 33 samples were re-analysed and 10 came back with profiles, an inquiry into Queensland's government-run forensics science laboratory was told yesterday.
The inquiry before Walter Sofronoff KC also heard six swabs taken from a suspected rape victim last November were initially ruled "insufficient for further DNA processing" but then linked to an alleged offender after being retested months later.
In the murder case, police Inspector David Neville, the head of the Queensland Police Service's DNA Management Unit, said a sample taken from the unnamed victim's calf had returned a usable DNA profile, which had identified an accused person.
But he said that when he raised the case with Catherine Allen, a senior manager within Queensland Health's Forensic and Scientific Services, citing concerns about DNA testing thresholds, he was told: "This was an outlier".
An interim report by Mr Sofronoff, released last week, found that between early 2018 and June this year, laboratory scientists gave "untrue" or "misleading" witness statements about the detection of DNA in some crime scene samples.
Mr Sofronoff found that under an agreement between Queensland Health and the Queensland Police Service, crime scene samples that did not contain quantities of DNA above a certain threshold were not processed further and were reported in witness statements as having "insufficient DNA for analysis".
He said this was despite the possibility of obtaining "an interpretable profile".
'Disturbingly high' number of sexual assault samples had enough DNA
Inspector Neville told the inquiry yesterday he repeatedly brought up concerns with Ms Allen about the thresholds after the murder case late last year.
But he said for months his concerns were rejected.
"I'd been asking for information or some sort of agreement between the two agencies that we would review the threshold and I just wasn't getting any traction," he said yesterday.
Inspector Neville told the inquiry yesterday that about 21,000 samples analysed in the four and a half years the threshold was in place were deemed to have insufficient DNA to be tested further.
But he said a police analysis of the 1,410 samples where a request was made for further testing, 549 — or more than a third — had yielded a profile.
He said that in sexual assault cases, a review found that a "disturbingly high" 66 per cent of samples initially deemed to have DNA amounts too small to be retested, were found to contain sufficient levels to obtain a profile.
But when he met with Ms Allen to discuss issues with the threshold on March 17 this year, she "made it clear she was displeased with me for providing the … data that I did".
"She actually said it wasn't appreciated," Inspector Neville said.
As concerns mounted this year that "we may be missing evidence that could identify an offender", he said he ordered his staff to review sexual assault cases.
In one case, highlighted at the inquiry, Inspector Neville said retesting of samples from a rape victim that were initially judged to have "insufficient DNA" had been able to corroborate her account.
The hearing continues.
