Omar Mateen, the identified by police as the gunman who opened fired at a gay nightclub in Orlando, Florida, early Sunday, killing 50 people and wounding 53 others, was described by his ex-wife as an abuser.

The FBI said it had twice investigated Mateen — who worked as a security guard and whose family came from Afghanistan — but was not able to substantiate any threats, including his ties to Moner-Abu Salah of Fort Pierce, Florida, who became the first U.S. suicide bomber in Syria. Mateen, 29, was not currently under investigation. The Department of Alcohol, Tobacco and Firearms said Mateen bought two weapons last week, a handgun and a long gun. He had two firearms licenses, a security officer license and a statewide firearms license.

Mateen was born in New York and lived in Port St. Lucie and Fort Pierce, Florida. His ex-wife said he was not particularly religious.

Moments before the the Pulse nightclub massacre, Mateen called 911 and pledged allegiance to the leader of the Islamic State group, Abu Bakr al-Baghdadi. He also referenced the 2013 Boston Marathon massacre, referring to the Tsarnaev brothers, who perpetrated the bombings.

The ex-wife told the Washington Post Mateen beat her during their brief marriage. She said she met him online and moved to Florida to marry him in 2009. Initially, she said, he “seemed like a normal human being.” But as time went on she realized he “was not a stable person. He beat me. He would just come home and start beating me up because the laundry wasn’t finished or something like that.”

The woman’s parents rescued her from the relationship. “They literally saved my life,” she said. The marriage was dissolved in 2011.

Mateen was born Omar Mir Sessique but changed his name several years ago, adding the Mateen. His father, Mir Seddique, said Sunday’s shooting had nothing to do with religion. Rather, he thinks his son was pushed over the edge after witnessing two gay men showing affection to each other.

“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,” Seddique, 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 said Mateen’s son is 3 years old.

Mateen worked as a security guard for G4S Secure Solutions, which was founded in Denmark in 1901 and now has 50,000 employees across the United States. The company provides a wide range of services, from security software and fraud investigations to corporate risk services.