Query on samples at state DNA lab

A SPECIALIST DNA scientist has told an Inquiry testing of bone samples at a state-run lab began returning contaminated results after a new cleaning procedure was introduced by someone without expertise who didn’t consult qualified specialists.

The Forensic Scientific Services’ Angelina Keller, who specialises in analysing samples, said the testing of bones and teeth from dead bodies was an accurate and consistent method to identify Deoxyribonucleic acid, or DNA, profiles.

In her 16-years operating in the highly specialised field of the forensic lab, she said testing of bones had always returned a single-source DNA profile.

But, Ms Keller told a commission of inquiry into DNA testing at the Queensland Health Forensic and Scientific Services (QHFSS) lab, that from November 2020, her results started to be tainted with the return of mixed DNA profiles.

“Since then, it has happened more frequently,” she said.

She also showed the inquiry a spreadsheet that outlined how mixed DNA samples had returned in about half the tests conducted between late 2020 and August this year.

The scientist told the hearing, at the Brisbane Magistrates Court, on Tuesday that when she noticed the contamination, she thought: “’We’ve got a problem, we’ve got to find out what’s going on.’”

“It was concerning me greatly,” she said.

The purpose of the inquiry, which started on June 13, is to examine a decision made in 2018 to not further test samples with low levels of DNA, resulting in thousands of pieces of evidence from crimes like rape and murder being ignored. This week the inquiry topics related to the culture of the state-owned laboratory and how this has impacted on various scientific issues.