Bias risk possible in police LGBTQI murder oversights

The inquiry delved into record-keeping practices of NSW homicide detectives and possible bias in dealing with the LGBTQI community.

Homicide Squad Detective Inspector Nigel Warren was quizzed about police practice in the deaths of more than two dozen LGBTQI people in Sydney, including failures to record evidence, oversights in investigations and tardiness in following leads.

Mr Warren conceded on Wednesday it was possible some investigators, especially in the '80s or '90s, were influenced by conscious or unconscious bias against supposed LGBTQI victims for the force's failure to adequately investigate their homicides.

"Because of society (at the time) generally, there was a risk," Mr Warren said. 

He agreed police investigation practices could be characterised as oversights and were deficient even by the standards of the day.

Record-keeping in the NSW police force was also held under the inquiry's microscope on Wednesday.

The detective inspector conceded he was aware of police officers retaining records from crime scenes after leaving the force despite that breaching rules.

"I've heard of that happening, yes," said Mr Warren, when asked by Counsel Assisting James Emmett whether he was aware of the practice.

Notebooks compiled by detectives involved in multiple homicide investigations were to be lodged with the force's record management system, but some have also gone missing, Mr Warren said.

The books may have been destroyed or never archived in the first place, but Mr Warren conceded there should be a record if the documents were destroyed.

"Whether that's happened, I couldn't tell you," he said.

NSW Police Superintendent Roger Best denied a tendency for officers at the time to work harder or be more thorough when investigating a case involving a victim they sympathised with.

"Some of the cases that I've been involved with are certainly touching on some level, but I don't know if that necessarily equates to any investigation that would be any different," he said on Wednesday.

"As an investigator going through that you're still doing processes."

The broad-ranging inquiry follows an internal police probe named Parabell that examined 88 deaths, determining 27 were gay hate crimes.

The latest block of hearings will wrap up on Thursday, with Supreme Court Justice John Sackar due to deliver a final report in August.