The gunman behind the shooting at Pulse nightclub visited the gay-friendly Orlando hotspot multiple times and used the gay dating app Grindr, patrons say – according to multiple reports. Federal officials are looking into reports that Omar Mateen visited Pulse nightclub multiple times before killing 49 people and wounding dozens in the deadliest mass shooting in American history, according to the CBS News. "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 told the Orlando Sentinel.