Four or more people who regularly went to Pulse, the gay Orlando nightclub where gunman Omar Mateen massacred 49 people early Sunday morning before dying himself in a shootout with police, said they believe they had seen him on earlier occasions there, The Orlando Sentinel reported late Monday afternoon.

Related: Trump Makes the Orlando Immigration Connection

“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,” Ty Smith, who also goes by the name Aries, told the publication.

He added that he had spotted Mateen at the club at least a dozen times.

The radical Islamic terrorist, who proclaimed allegiance to ISIS in a 911 call before or during the shooting, had apparently seen two men kissing recently and become angered by that, Mateen’s own father told news sources after the attack in Orlando.

According to witnesses, “Mateen was also a regular at the club and exchanged messages with at least one gay man on a gay dating app,” Gawker reported.

Mateen, who was American born, was divorced and had a three-year-old son.

MSNBC host Chris Hayes said he spoke to a man who claimed both he and a friend received messages from Mateen via a gay dating app, an article in Gawker also reported.

Sitora Yusufiy, Mateen’s ex-wife, believed something was very wrong with the man she had married and fled what she called an abusive marriage in 2009 with the help of her parents. Yusufiy lives with her fianće in Boulder, Colorado, The New York Times reported.

Although Yusufiy “let that chapter of my life go a long time ago,” the man who “hurt and traumatized” her returned to her life by committing the deadliest mass shooting in U.S. history. She was interviewed by FBI agents after the attacks on Sunday.

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In addition to killing 49 people, Mateen also wounded at least 53 people.

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