Early Sunday morning, June 12, Omar Mateen walked into a Latin party at the gay nightclub Pulse in Orlando and gunned down 49 people, wounding dozens of others before being shot and killed by police. It was the worst mass shooting in U.S. history. Making sense of the tragedy seemed impossible, not only because of the profound loss, but also because of the political hysteria and conspiracy theories inherent in the shooting—was the killer motivated by ISIS-backed terrorism, antigay hatred or perhaps even HIV stigma?

Almost from the beginning, HIV was part of the horrific headlines. Initial articles didn’t directly link the gunman with HIV; instead, they highlighted the fact that, according to law, men who have sex with men are not allowed to donate blood unless they’ve been celibate for a year. Several media outlets also reported that Barbara Poma, who cofounded Pulse, named the club in memory of her older brother, John, who died of AIDS-related illness in 1991.

Then on June 21, Spanish TV station Univision ran an interview with “Miguel,” a man who claimed he had a sexual relationship with Mateen. Miguel, wearing a disguise, explained that the shooter felt rejected by gay Latinos and feared he had been exposed to HIV. According to Miguel, Mateen was upset over a three-way with two Puerto Rican men, one of whom disclosed later that he has HIV. “[Mateen] was terrified that he was infected,” Miguel told Univision. “I asked him, ‘Did you do a test?’ Yes. He went to the pharmacy and did the test.… It came out negative, but it doesn’t come out right away. It takes four, five months.” The FBI later confirmed Mateen was HIV negative. Needless to say, not everyone believes Miguel’s story.