A Special Commission of Inquiry has examined the death of Walter John Bedser, 47, who died after he was stabbed multiple times in the chest in his Parramatta antiques shop in December 1980.
The inquiry on Wednesday is part of a wider probe into police handling of suspected LGBTQI hate crimes between 1970 and 2010.
Counsel assisting Christine Melis told the inquiry Mr Bedser was known to be gay among his friends and associates.
At the time of the murder, multiple witnesses saw the injured Mr Bedser and a man running from the shop.
Police published a description and identikit image of the presumed suspect but he was never identified.
The man was believed to have bought a sheath knife used in the murder from a nearby store shortly before Mr Bedser was killed, suggesting a degree of premeditation.
No persons of interest were identified in the initial police investigation and many witnesses are now dead or unable to be located.
"Some witnesses were either not spoken to at all, or not pursued," Ms Melis said.
The knife used in the attack was found on the floor of the shop but there was no record it had been examined and it had since been lost, a blunder Ms Melis described as "plainly deplorable".
A 2018 report by NSW Police into 88 potentially hate-driven murders found it would be reasonable to suggest Mr Bedser liked young males and employed them at his shop with the intent of engaging in some type of sexual activity with them.
"There is abundant evidence that Mr Bedser had had sexual relations with, or had propositioned, a number of teenage boys, some of whom had at one time or another been employed by Mr Bedser in his shop," the inquiry was told.
One boy was aged 17 at the time and told police he and Mr Bedser would have oral sex in a room above the shop.
The inquiry was told there were tensions between Mr Bedser and the 17-year-old's family and at least two parents had come to know or suspect something of the nature of their sons' relationships with the antiques dealer.
"There is a hypothetical possibility that one of the fathers of one of these youths, or another family member or associate, killed Mr Bedser in retribution for his actual or feared sexual interactions with that youth," the inquiry was told.
The possibility of a revenge attack or the question of gay hate bias in the proceeding police investigation cannot be definitively answered although counsel assisting said the use of homophobic language in some of the police documents was "striking".
Consultant forensic psychiatrist Dr Danny Sullivan found in his 2022 report there were "no features of the crime scene suggesting hate crime" but the purchase of a knife beforehand suggested the killer "had intended to kill Mr Bedser specifically".
Hearings will continue in front of Justice John Sackar.
