Almost three decades after an American's body was found at the bottom of a Sydney cliff in what was first ruled a suicide, a judge in Australia has unlocked the mystery of what happened to him.

Mathematician Scott Johnson's naked body was found at the bottom of a 196-foot cliff where gay men were known to hang out in 1988.

Ever since then, his family has had to live with the uncertainty surrounding his death.

Years later, evidence emerged that gangs had been targeting gay men in the cliffs near Sydney. The most recent inquest was the third to investigate the circumstances surrounding Johnson's death.

State Coroner Michael Barnes ruled Thursday that Johnson "fell from the cliff top as a result of actual or threatened violence by unidentified persons who attacked him because they perceived him to be homosexual."

The coroner also found it was most likely that more than one person was responsible for the attack that led to Johnson either being pushed off the cliff, or him falling while trying to run away.

His body was found below a cliff that was a known gay meeting place.

Johnson was born in Los Angeles and was openly gay.

The ruling comes as Australians voted earlier this month in favor of making same-sex marriage legal. Legislation that would do so is making its way through Parliament.

His brother, Steve Johnson, wants police to bring the killers to justice.

“It was anguishing losing Scott,” Steve said to the New York Times. “Now I know his final moments were filled with terror, and that’s just like living it all over again.”

The Associated Press contributed to this report.