Mateen came to the attention of federal authorities twice prior to being identified as the gunman in the Orlando nightclub mass shooting, a senior law enforcement source told The Daily Beast.
The source reports that Mateen became a person of interest in 2013 and again in 2014.
The FBI at one point opened an investigation into Mateen but subsequently closed the case when it produced nothing that appeared to warrant further investigation.
“He’s a known quantity,” the senior law enforcement source told The Daily Beast. “He’s been on the radar before.”
Mateen was an American citizen, born to Afghan parents in New York in 1986 and was living in Port St. Lucie, Florida, US officials said.
Ronald Hopper, an assistant agent in c-harge of the FBI’s Tampa Division, told reporters Mateen may have had leanings toward Islamic extremism.
“We do have suggestions that the individual may have leanings towards that, that particular ideology,” Agent Hopper said at a news conference. “But right now we can’t say definitively, so we’re still running everything around.”
Terrorist groups have not claimed responsibility for as yet, but a social messaging account linked to the Islamic State gloated about the attack.
A Twitter account associated with the group posted a photo purported to be Mateen.
“The man who carried out the Florida nightclub attack which killed 50 people and injured dozens,” the caption accompanying the photo read.
In contrast, Mateen’s father, Mir Seddique, told NBC:“This has nothing to do with religion.”
Seddique said his son became angry when he saw two men kissing in Miami a few months ago. He believes that incident may be related to Sunday’s shooting.
“We are saying, we are apologising for the whole incident. We weren’t aware of any action he is taking. We are in shock like the whole country.”
Orlando police officers seen outside of Pulse nightclub after a fatal shooting and hostage situation on June 12, 2016 in Orlando, Florida. Picture: Getty.Source:AFP
Seddique also told NBC that Mateen had a three-year-old son and that he worked a security job at Indian River State College, which he also attended.
Speaking on the condition of anonymity, Mateen’s ex-wife told the Washington Post that he was violent and mentally unstable and beat her repeatedly while they were married.
The ex-wife said she met hiim online about eight years ago and decided to move to Florida and marry him.
At first, the marriage was normal, she said, but then he became abusive.
“He beat me. He would just come home and start beating me up because the laundry wasn’t finished or something like that,” said his ex-wife.
She told the paper that Mateen wasn’t very religious and worked out at the gym often.
“He seemed like a normal human being,” she said.
She said in the few months they were married he gave no signs of having fallen under the sway of radical Islam.
The ex-wife said her parents intervened when they learned Mateen had assaulted her. Her father confirmed the account and said that the marriage lasted only a few months.