In December 1988, Scott Johnson, a gay American mathematician, was found dead beneath a cliff in Sydney, Australia. His death was quickly determined to be a suicide. But Steve Johnson, Scott's older brother, had doubts and would spend the next 35 years trying to solve the mystery of Scott's death. He could have never imagined the tinderbox he would crack open—a wave of anti-gay violence, which was systematically ignored for decades.

• Steve Johnson