Freddy doesn't know why police have chosen not to believe his shameful story, or what possible motivation he could have for lying about his involvement in violence against gay men in the 1980s.

The 46-year-old took Detective Chief Inspector Pamela Young and Detective Sergeant Penny Brown to the old "gay beat" on North Head near Manly in 2013 and told them how, as a teenager, he acted as the lure so his bigger mates could bash the homosexual men who went to this cliff-top area for casual, anonymous sex.

Young and Brown had met "Freddy" while leading Strike Force Macnamir, a two-year re-investigation of the death of a 27-year-old American mathematics prodigy, Scott Johnson, whose fall from those cliffs in December 1988 was originally ruled a suicide – a finding they still believe carries weight.

The State Coroner ordered an extraordinary third inquest into the death this week and it will explore the belief of brother Steve Johnson - whose $1 million private investigation has put him in open conflict with Young – that Scott was pushed and it was among a spate of gay-hate murders in Sydney.

Young, in her 445-page report for the coroner, identifies Freddy as NP99 and says: "On its face this information may be a breakthrough for the investigation. This is the first and only information available to the investigation of actual violence being done to gay men at North Head."

Further, Young points out, police knew that Freddy's friends, NP98 and NP10, were convicted of gay-gate crimes in the area, including at nearby Reef Beach.

But Young is convinced Freddy's "perplexing" evidence, for motives she cannot explain, is a lie. She concludes the trio never preyed on gay men on North Head.

Asked if he was offended this week, Freddy told Fairfax Media: "Well, in a way yes, in a way no … if that person takes it either way it doesn't matter to me as long as I got that off my chest."

But he said he told Young "there wasn't any case where we went there and we got some guy there and we pushed him off". Nor did he believe his friends would have killed Johnson. "And she said, 'OK, that's the bottom line … let's just leave it at that.' "

Young's report goes much further than dismissing Freddy. Despite all the publicity generated by the Johnson family in recent years, she says, not a single victim has come forward to say he was bashed at this beat, and there was no record of any such victim presenting at the nearby Manly Hospital.

Her bombshell punchline: "Based on these realities, it is not unreasonable to draw an inference that no crimes of personal violence occurred at the North Head gay beat and certainly none that required medical treatment."

It is not only unreasonable but a breathtaking leap of logic, says Steve Page, a former homicide detective whose investigation led the 2005 coronial finding that two gay men, and probably a third, were murdered on the Bondi-Tamarama cliffs in the late 1980s.

Young's report is critical of "flaws" in Page's investigation. Page, who says "foul play is a real likelihood in Scott's case", will save his detailed criticism of Young's report for the third inquest, which may not start in earnest until next year. But he rejects the notion that Steve Johnson "is getting Rolls Royce justice".

On the ABC's Lateline this week, Young accused former police minister Mike Gallacher of "kowtowing" to the Johnsons in 2013 and improperly asking police to divert resources to their case while hundreds of other families, not all "so well off", also wanted answers to unsolved deaths.

Gallacher rejects that criticism and Page says a fair-minded person would realise the then minister was sympathetic to the flaws in the Johnson investigation and was "prepared to cut through the crap".

"I witnessed institutionalised resistance by NSW police to properly investigate gay-hate crime," Page says. "I don't think this class of victim was wholesome enough for them. It doesn't appear much has changed."

On Lateline Young was asked if the original police investigation after the death in December 1988 was flawed. "Not at all," she said. "It was to the standard of the day."

The lead investigator in 1988 was then Detective Sergeant Doreen Cruickshank, who told the first coroner, Derrick Hand, that the area where Scott Johnson died was not frequented by homosexual men. If it had been, she said, it would also have been frequented by people who disliked them and who would "assault them or rob them or cause them some harm".

Young's report now confirms it was a gay beat but says, unlike other beats, it wasn't one frequented by violent men who disliked gays.

While unclear on Freddy's motives for coming forward, she does raise suspicions about his claims to have won three $10,000 poker machine jackpots between March and July, 2013, and the assessment of AUSTRAC, the agency that monitors financial transactions, of these "unhealthy" deposits. She also raises Freddy's possible mistaken belief that he could be entitled the government's $100,00 reward and intercepted phone call in which Freddy mentions that Steve Johnson has offered $1 million for information to solve the case.

Freddy tells Fairfax Media he made clear from the outset that he was not interested in any reward, and that he has never received a cent from the Johnsons. They insist they have never paid him.

He says the Dee Why RSL would have recorded those pokies wins, and some bigger ones.

But Freddy says of Young: "I'm not bitter … She's got to prioritise her cases … She's scrutinised me and now she's got to move on to other cases, other families. I can see her point of view. I've got to carry on; she's got to move on."