A gay nightclub here was the scene early Sunday of the worst terror attack in U.S. history since 9/11. * 50 people were killed inside the Pulse club and at least 53 people were injured, police say. * The gunman was Omar Mateen of Ft. Pierce, Florida, a law enforcement source told CNN. * Orlando police shot and killed Mateen * Mateen called 911 around the time of the attack to pledge allegiance to ISIS and mention the Boston bombers, according to a U.S. official. "It appears he was organized and well-prepared," Orlando Police Chief John Mina said early Sunday. The shooter had an assault-type weapon, a handgun ... (full story)