Omar Mateen, the 29-year-old American-born Muslim gunman who killed 49 while pledging allegiance to the Islamic State group, was reportedly a closet homosexual and a regular at the LGBT nightclub he attacked.
Jim Van Horn, also a regular at the Pulse nightclub in Orlando, Florida, where the massacre occurred on Sunday, told The Guardian he believes Maten was gay, as he had been to the venue on numerous occasions and often attempted to pick up men.
"On the weekend sometimes he would be there, sometimes he'd miss a couple of weeks and be in again," Van Horn, 71, told the outlet. "He was a regular. We consider that regular. He was trying to pick up people - men. He was a homosexual and he was trying to pick up men. He would walk up to them and he would maybe put his arm around them or something and maybe try to get them to dance a little or something and then go buy a drink or something."
"That's what people do at gay bars, you know, that's what we do," he added.
When asked how he responded after seeing Mateen's picture, Van Horn said, "[We said] oh, that makes sense - that's Omar."
At least four other customers at Pulse told local news outlet the Orlando Sentinel that they, too, had seen the shooter at the nightclub in the past.
"Sometimes he would go over in the corner and sit and drink by himself, and other times he would get so drunk he was loud and belligerent," said Ty Smith, one of the customers.
"We didn't really talk to him a lot, but I remember him saying things about his dad at times," he added. "He told us he had a wife and child."
The Los Angeles Times reported earlier on Monday that Mateen had visited the Pulse nightclub on several occasions before the shooting, and had even used a gay dating app to contact regulars at the club.
Authorities are looking into Mateen's motives for carrying out the deadliest shooting in U.S. history, and revealed that the Fort Pierce, Florida native, who died at the hands of a SWAT team, had been questioned on two separate occasions by FBI agents.
Mateen, who worked as a security guard, had apparently been investigated back in 2013 for declaring he was a member of Hezbollah, a Lebanese Shiite militia group, and in 2014 on suspicion of watching videos by Al Qaeda propagandist Anwar Awlaki.
During the standoff with police on Sunday, Mateen proclaimed his allegiance to the Islamic State and his support for the Muslim brothers who set off two bombs at the 2013 Boston Marathon, police said.
Mateen's former wife, Sitora Yusufiy, told authorities her ex-husband had a violent temper, but could not confirm whether his pledged allegiance to the Islamic State terror group was the main driving force behind his actions on Sunday. She also revealed her husband exhibited "gay tendencies" throughout their brief marriage.
"After [our wedding] he confessed to me about his [recent] past, and [how] he very much enjoyed going to clubs and the nightlife ... I feel like it's a side of him or a part of him that he lived, but he probably didn't want everybody to know about," she said, according to the Sydney Morning Herald.
Noor Mateen, Mateen's second wife, is being considered for possible criminal charges, officials say, as she may have known something about the assault in advance but claims she tried to talk him out of it.
Meanwhile, James Comey, director of the FBI, said there were "strong indications of radicalization by this killer, and of potential inspiration by foreign terrorist organizations". Comey added that he was "highly confident" that Mateen had been radicalized at least in part online and said that fear "is what these savages want."
"We know that this killing is upsetting to all Americans. We hope that our fellow Americans will not let fear become disabling."