Omar Mateen (November 16, 1986 - June 12, 2016) was responsible for one of the deadliest mass shootings at the Pulse Gay Nightclub Shooting in Florida. He killed 49 and wounded 58 on June 12th, 2016 before being killed in a shootout with the police.
Previous to the shooting he had been investigated by the FBI to connections to terrorism. It is said that he carried out the Pulse Nightclub Shooting for the Islamic State. Shortly afterwards, people came forward saying that Omar had homosexual tendencies of his own and very well may have been gay himself. During the shooting he called 911 and referenced the Boston Bombers, along with an acquaintance of his who had died in a suicide bombing in Syria.
This is the New York Post Newspaper that was put out after the shooting.