In an exclusive interview with Univision Noticias
on Tuesday, the man, identifying himself only as Miguel, rejected claims that it was an act of terrorism.
“The truth is that he didn’t do it for terrorism. In my opinion he did it for revenge,” he said.
He said Mateen was angry and upset after a man he had sex with later revealed he was infected with the HIV virus.
Asked why he decided to come forward with his story, Miguel, wearing a disguise, said he felt it was his “responsibility as a citizen of the United States and a gay man.”
He said he had been approached by the FBI and been interviewed three times in person by agents.
Univision said it was unable to verify his account but the FBI had confirmed that it met with him.
Miguel, speaking in fluent Spanish and accented English, said he and Mateen had met on a gay dating app and became “friends with benefits.” The pair had allegedly met between 15 and 20 times. Miguel never learned Mateen’s name, however.
He described Mateen as a “very sweet guy,” who loved to be cuddled.
“He adored Latinos, gay Latinos, with brown skin – but he felt rejected,” Miguel said. “He felt used by them – there were moments in the Pulse nightclub that made him feel really bad. Guys used him. That really affected him.”
In the June 12 shooting, 49 people were killed
and dozens were wounded. Mateen was killed in a shootout with police hours later. Most of the dead were Hispanic.
Investigators are still looking for motives behind the shooting.
Attorney General Loretta Lynch told reporters on Tuesday that investigators may never be able to pinpoint a single motive and have not ruled out witness reports suggesting Mateen might have had gay interests.
Miguel said Mateen was especially upset after a sexual encounter with two Puerto Rican men, one of whom later revealed he was HIV positive, he added.
“He [Mateen] was terrified that he was infected,” Miguel said. “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 to five months.”
“When I asked him what he was going to do now, his answer was: 'I'm going to make them pay for what they did to me',” Miguel said.