What to Know About the Orlando Pulse Nightclub Shooter

Authorities on Sunday identified the gunman behind the deadly Orlando nightclub shooting as Omar Mateen. The shooter carried out the worst mass shooting in U.S. history when he opened fire inside a crowded Florida nightclub early Sunday, gunning down at least 50 people and wounding another 53. He was later killed in a shootout with police. Here’s what we know about him so far:

What did he do?

Mateen shot into a crowd of hundreds of people inside Pulse Orlando, a popular gay nightclub, where he held people hostage, about 2 a.m. on Sunday, police said. He was armed with an assault rifle and a handgun and also had a “suspicious device,” Orlando Police Chief John Mina said. Mateen was killed during a gun battle with police about 5 a.m. when a SWAT team entered the club to rescue the hostages, authorities said.

Who was he?

Mateen, who had reportedly made calls to 911 early Sunday stating his allegiance to ISIS, was flagged on the FBI’s radar in 2013 and then again in 2014, FBI Assistant Special Agent in Charge Ron Hopper said at a news conference. Both investigations were closed after inconclusive interviews.

The agency questioned Mateen twice after being alerted to him speaking of possible terrorist ties in 2013 but officials were “unable to verify the substance of his comments.” The 29-year-old came to the FBI’s attention again in the next year over possible ties to an American suicide bomber, Hopper said.

The FBI closed that investigation after authorities determined that contact between the two were minimal. Mateen did not pose as a threat at that time, Hopper said.

Mateen is a U.S. citizen who was born in New York and later moved to Port St. Lucie, Florida, authorities said. He was not under investigation or surveillance at the time of the Orlando nightclub massacre, according to the FBI. Mateen had legally purchased at least two firearms—a handgun and a long gun— within the last week, the ATF said.

A security company, G4S, said in a statement Sunday that Mateen had been employed there since 2007, adding that it was “deeply shocked” by the shooting. “We are cooperating fully with all law enforcement authorities,” the company said.

Mateen worked at a gated retirement community in South Florida for G4S. He passed the company’s screening and background checks in 2007 and again 2013 when his employers learned he had been questioned by the FBI, according to the company’s spokeswoman, Monica Lewman-Garcia.

“We were not made aware of any alleged connections between Mateen and terrorist activities,” the statement said. “Our thoughts and prayers remain with the victims of this unspeakable tragedy, and their friends and families.”

What was his motive?

Little is known so far on what prompted Mateen to attack the nightclub, and the shooting is under investigation. The assault was “more likely than not ideologically motivated,” Grayson said. “It’s no coincidence that the attack took place where it did and where it did,” he added.

ISIS has claimed responsibility for the shooting, saying the attack was “carried out by an Islamic State fighter” in a report on its official Amaq news agency. According to NBC News, Mateen not only pledged allegiance to ISIS when he called 911 before the shooting, but also mentioned the 2013 Boston Marathon bombings and two brothers who carried it out.

Mateen’s motive was also a mystery to his father, Mir Seddique, who told NBC News that the shooting had “nothing to do with religion” and may have been sparked by an earlier incident that involved gay men. Seddique said his son got angry a couple of months ago when he saw two men kissing in Miami, according to NBC.

“I apologize for what my son did. I don’t know why he did it. He is dead, so I can’t ask him. I wish I knew,” he said. “We weren’t aware of any action he is taking. We are in shock like the whole country.”

According to the Washington Post, Seddique has been identified as a supporter of the Afghan Taliban in his YouTube videos.

Mateen’s ex-wife described Mateen as an abusive man in an interview with the Post, adding that she didn’t know him to be very religious and that he worked out frequently. “He was not a stable person,” said the ex-wife, who was not named. “He would just come home and start beating me up because the laundry wasn’t finished or something like that.” The two met online about eight years ago, according to the newspaper.

Yusufiy’s family had to “rescue” her from the abuse, she said Sunday at a news conference, according to CNN. “[My family] had to pull me out of his arms and find an emergency flight,” she recalled.

Syed Shafeeq Rahman, the iman of the Fort Pierce mosque where Mateen worshipped, said he attended prayer three to four times per week and never demonstrated any violent capabilities, Agence-France Presse reports. After services, he wouldn’t socialize, but would smile and shake hands, the iman said.

However, the New York Times reports that a former co-worker said that Mateen “talked about killing people all the time.” Daniel Gilroy, who worked at the GS4 security company with Mateen, told the Times that Mateen “was just agitated about everything, always shaken, always agitated, always mad.”