A former top NSW police officer has denied at a gay hate crimes inquiry that he viewed the unsolved death of an American mathematician as "a game" against the man's family.

Former deputy commissioner Michael Willing was on Monday quizzed about the 1988 death of US man Scott Johnson, whose case was ruled a suicide before it was reopened in 2012 following family pressure.

A coroner in 2017 determined the matter involved human intervention and in February Scott White pleaded guilty in the NSW Supreme Court to Mr Johnson's manslaughter.

Mr Willing was asked about the view of investigating police, including former detective Pamela Young, that Mr Johnson's death was likely suicide.

Mr Willing said he "ultimately" was not able to determine if Mr Johnson's death was homicide, suicide or misadventure, saying his own view on the case changed over time.

"I thought there was no evidence to indicate it was a homicide," he said.

He denied sharing Ms Young's attitude that Mr Johnson's family was wrong to keep "pushing" the homicide theory.

He also rejected the proposition he considered the family to be police opponents but conceded the relationship between police and the family became "adversarial".

"I didn't consider defeating them (the Johnson family) to be an objective," he said.

Taken to a text message exchange with Ms Young in which he wrote "We will work through and come out on top", Mr Willing said he was "attempting to appease" his colleague.

"She was extremely upset I didn't see it as a game with a winner or loser."

Mr Willing was asked about Ms Young's interview on ABC TV's Lateline in 2015 that pointed to a likely suicide.

He agreed, after being taken to notes related to the "explosive" interview, that it was "crystal clear" Ms Young thought the death was due to suicide and would not be solved.

Mr Willing said the ABC coverage plan was not discussed with him and told the inquiry it did not cross his mind that a formal interview had occurred until the day the story aired.

He agreed he did not "remonstrate" with Ms Young in the lead up as he assumed the interview related to a police-authorised doorstop outside Glebe Coroner's Court.

Commissioner John Sackar asked: "It did not give you any concern that she was telling you that she had recorded an interview and it was going to be on Lateline that night?"

"No," the witness replied.

"You trusted her that whatever it was would be discrete and appropriate," Commissioner Sackar then suggested.

"Yes," Mr Willing replied.

Mr Willing agreed that although surprised at parts of the interview, he made no attempt to contact Ms Young in its immediate aftermath.

He accepted that he had her contact details and could have contacted her afterwards.

"What were you thinking?" the commissioner asked, to which Mr Willing replied he knew it would be discussed "first thing" the next day.

Ms Young was not disciplined by police for her unauthorised activities, he said.

Mr Willing previously faced the inquiry in February over Strike Force Neiwand's probe of more than 50 suspects involved in the murders of three gay men in the 1980s.

The inquiry, which adjourned until Thursday, has probed unsolved suspected LGBTQI hate crime deaths in NSW between 1970 and 2010.

The commission is due to deliver its report to NSW Governor Margaret Beazley in August.