(RNN) – Omar Mateen killed 50 people and injured 53 in a shooting early Sunday morning at a gay night club called Pulse in Orlando, FL.

A standoff between Mateen and Orlando police lasted three hours. Mateen had about 30 hostages in the club and police said he was wearing a device – but would not say if it was explosive. Police used a controlled explosion and broke through a wall, and shot and killed the suspect.

The city of Orlando is releasing the names of those killed as next of kin is notified. That list can be found here.

Here’s what we know about Mateen who carried out the largest mass shooting event in U.S. history and the largest terror attack since 9/11:

  • He had two firearms licenses that expire in 2017. On June 6, Mateen legally purchased a Glock pistol from a St. Lucie County gun store that was found at the scene of the shooting. The FBI also said he purchased another gun last week, but details on that firearm have not been released.
  • Mateen worked for G4S Secure Solutions as a security guard.
  • Mateen called 911 about 20 minutes into the attack and claimed allegiance to the Islamic State and mentioned the Boston Marathon bombing.
  • The FBI investigated Mateen for possibly sympathizing or having ties with Islamic extremism, but closed the case because there was not enough evidence to charge him. The FBI interviewed Mateen in 2013 and 2014.
  • The U.S. citizen was born in New York City in 1986, but lived in Fort Pierce, FL. His parents, who were born in Afghanistan live in Port St. Lucie, FL. Officials are searching both residences.
  • Mateen’s father, Seddique Mateen, told the media that his son expressed anti-gay opinions, saying he became angry when he saw two men kissing in Miami recently.
  • Seddique Mateen, Omar’s father, appeared on a television program called Durand Jirga Show that is created in California and is known for pro-Taliban views and anti-U.S. rhetoric.
  • He married a Sitora Yusufiy, from New Jersey, who he met online eight years ago, however, they divorced in 2011. She told The Washington Post that her ex-husband beat her repeatedly, and that her family had to rescue her. She also said that Omar Mateen was not particularly religious at the time.
  • Mateen had a child with another woman after his divorce, who also left him.
  • Friends said he became more religious after the divorce, according to The Washington Post.
  • People who attended mosque with him gave conflicting reports that he was either quiet or aggressive, The Post reports.
  • A former co-worker told WPTV that Mateen was “angry and aggressive in nature” and also “a bigot to every class of person. Dan Gilroy asked his supervisors to reassign him so he would no longer work with Mateen, but that request was denied. Gilroy said he would lose his temper, hit things, and say racist, sexist and homophobic remarks.

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