Details about the shooter and his possible motives are slowly emerging in the wake of the Orlando nightclub mass shooting that left 50 people dead and 53 others injured early Sunday.

Here's what we know about the Orlando gunman.

• The gunman has been identified in news reports as 29-year-old Omar Mateen, a U.S. citizen from Port St. Lucie, Fla., the Associated Press reported. Mateen was killed in a shootout with SWAT officers.

• NBC News, citing multiple unnamed law enforcement sources, reported that Mateen allegedly called 911 prior to the shooting and swore allegiance to the so-called Islamic State group.

• Mateen is believed to have used an AR 15-style assault rifle on the shooting victims, CBS News reported. Police also discovered a handgun at the scene.

AP/Phelan M. Ebenhack - apimages.com

• The Wall Street Journal reported that Mateen possessed "two firearms licenses, a security officer license and a statewide firearms license." He worked as a private security guard, CNN reported.
• An unnamed senior law enforcement official told The Daily Beast that the FBI considered Mateen "a person of interest in 2013 and again in 2014." An investigation was reportedly opened into Mateen, but that investigation was closed "when it produced nothing that appeared to warrant further investigation."

• Mateen's father told NBC News that the shooting "has nothing to do with religion." He said that Mateen became angry after seeing two men kiss in Miami months ago and believes that may have motivated the attack on the gay nightclub, Pulse Orlando.
• An ex-wife of Mateen told The Washington Post that the gunman was "not stable" and physically beat her. She said that he was not particularly religious and worked out frequently while they were married.
• Law enforcement officials are currently investigating whether the shooting was an act of terrorism.

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