June 14, 2016 6:39 am Orlando Shooter a Nightclub Regular? Reports indicate that gunman Omar Mateen, who opened fire on Pulse nightclub in Orlando, Florida killing 49, may have been a regular at the club as well as sent messages on online gay dating sites. US & World Videos 2:54 Penn leaders reiterate to pro-Palestinian protesters that they need to pack up camp 1:44 Pro-Palestinian protesters remain on UPenn's campus despite warnings to disband 1:30 Protests calling for ceasefire continue at Penn 6:33 Family affair: Former Eagle and new Eagle Jeremiah Trotter and Jeremiah Trotter Jr. speak out 0:20 Teen girl shot in Southwest Philly, suspect in custody