A bid by NSW Police to exclude a high-profile murder case from a gay hate inquiry has been rejected.
The death of US mathematician Scott Johnson is one of dozens of cases under the spotlight at a special commission of inquiry into suspected gay hate crimes in Sydney between 1970 and 2010.
The 27-year-old died after he was punched at a gay beat on Sydney's northern beaches and his naked body was found at the base of a cliff at North Head in December, 1988.
Police initially ruled the death a suicide before family pressure, a series of inquiries and a $2 million reward sparked renewed interest in the cold case.
Evidence from three police strike forces - Macnamir, Parrabell and Neiwand - has been the subject of the latest inquiry.
Strike force Macnamir, established in 2013 to reopen the matter, found there was "no reason to suspect" Mr Johnson's death "involved violence".
A 2017 inquest determined his death was a homicide with findings that he "died as a result of a gay hate attack" viewed by some police as a "defeat".
In the latest development, Scott Phillip White pleaded guilty to throwing the punch that ultimately caused Mr Johnson to fall to his death.
Justice Robert Beech-Jones dismissed "what appears to be an absurd suggestion (by police) that Dr Johnson killed himself" when sentencing White to nine years' jail last month.
Police have since argued for key material from the investigation to be ignored, fearing it will appear officers were part of a "grand conspiracy" to play down bias crimes.
The force said Mr Johnson's death was outside the inquiry's terms of reference on the basis the matter was not unsolved, the man responsible for his death identified as gay and a sentencing judge did not find the death to be motivated by gay hate.
But the inquiry's commissioner Justice John Sackar on Tuesday ruled its terms of reference were much wider and answers to questions such as how and why Mr Johnson died were still not known.
The court did not make a finding beyond reasonable doubt that White was motivated by gay hate bias, but did not rule out the possibility, he said.
He also found not drawing on the findings from inquiry would be "to waste a valuable opportunity to help advance the public interest".
Justice Sackar will deliver a final report next month.
