In 1988, American mathematician Scott Johnson, 27, died after falling off a cliff in Sydney, Australia. His death was initially classified as a suicide, but this week, authorities arrested a suspect, a 49-year-old male, and charged him with murdering Johnson.

Johnson's death became an open case in 2012, and authorities determined in 2017 that it was likely the result of an anti-gay hate crime. A Sydney police review of suspicious deaths from the 1970s to 2000 found that at least 27 men were murdered by homophobic attackers during that period.

Johnson's brother Steve Johnson, a former AOL executive, said news of the arrest of the suspect was "emotional" for the family — "for my three kids who never got to know their uncle and admire him not just because of his brilliance but because he courageously lived his life the way he wanted to," he said in a statement.

In 2018, the Australian government offered a reward of 1 million Australian dollars ($647,260) for information leading to the arrest of Johnson's killer. Earlier this year, Johnson's family matched it.

"I hope the friends and families of the other dozens of gay men who lost their lives find solace in what's happened today and hope it opens the door to resolve some of the other mysterious deaths of men who have not yet received justice," Johnson said.

Nicolas Parkhill, the CEO of ACON, Sydney's largest LGBTQ health organization, urged authorities to continue to investigate other possible murders.

"The deaths and disappearances of gay men and transgender women and the epidemic of violence in Sydney and [New South Wales] during the 1970s to 1990s has left a traumatic legacy," Parkhill said in a statement. "Bias-motivated violence and murder are crimes that hurt both physically and emotionally, and the impact is felt deeply, both individually and communally."

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