Officials have identified Omar Mateen as the shooter in a deadly attack on a gay nightclub in Orlando, where 50 people were killed and 53 more were injured early Sunday morning.

In a press conference, Florida Congressman Alan Grayson said Mateen was a 29-year-old from Port St. Lucie who lived in Fort Pierce, Fla. Grayson said Mateen was a U.S. citizen, but added that that was "not true of other family members of his."

Grayson, whose district includes the area of the massacre, suggested the massacre was ideologically motivated.

"Let me put it this way," he said, "the nationality of family members is indicative."

Law enforcement sources told NBC News that Mateen called 911 moments before the deadly shooting spree to pledge allegiance to the leader of ISIS. But his family members paint him as an unstable man who was likely motivated by his hatred of the LGBT community. 

"We were in Downtown Miami, Bayside, people were playing music. And he saw two men kissing each other in front of his wife and kid and he got very angry," Mir Seddique, Mateen’s father, told NBC News on Sunday. "They were kissing each other and touching each other and he said, 'Look at that. In front of my son they are doing that.' And then we were in the men's bathroom and men were kissing each other."

Seddique added, "This has nothing to do with religion,” and that, “We are in shock like the whole country.”

Seddique also told NBC News that Mateen was husband and father to a 3-year-old son, and that he worked a security job at Indian River State College, which he also attended.

Mateen’s ex-wife, speaking to the Washington Post on the condition of anonymity because she feared for her safety, also said he wasn’t very religious, and gave no signs of being a radical Islamist.

“He seemed like a normal human being,” she told The Post, but added that he was violent and mentally unstable, and beat her often during their marriage.

“He was not a stable person,” she said. “He beat me. He would just come home and start beating me up because the laundry wasn’t finished or something like that.”

 

Ron Hopper, the FBI assistant agent in charge of the agency's Tampa division, told reporters that investigators were "looking at all angles right now" to find a motive.

"We do have suggestions that that individual may have leanings towards that, that particular ideology [Islamic extremism]. But right now we can’t say definitively, so we’re still running everything around," Hopper said.