WFTV Investigates: Who was Pulse mass shooter, Omar Mateen?

Updated:

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ORLANDO, FL. - The man responsible for killing at least 50 people inside the Pulse nightclub early Sunday has been identified as Omar Mateen, 29, of Fort Pierce in St. Lucie County. 

Officials said at least 50 people, including the shooter, were killed and 53 others were injured at the nightclub, making it the deadliest mass shooting in U.S. history. 

Mateen’s ex-wife said he was "mentally unstable and mentally ill."

Raw: Ex-wife says gunman was 'mentally unstable'

Sitora Yusifiy, speaking to reporters in Boulder, Colorado, said Mateen was bipolar and also had a history with steroids.

She said that in the four months they were together, he cut her off from her family and regularly beat her. She said that her family visited her and saw she wasn't OK and rescued her from the situation.

Yusifiy said they literally pulled her out of his arms. She said she left all her belongings and has had no contact with him for seven or eight years.

She said Mateen was religious, but she saw no signs of radicalism.

Of the nightclub massacre she said, "There was no sign of any of this at all."

In a 911 call from the club, Mateen professed allegiance to the leader of the Islamic State, Abu Bakr al-Baghdadi.

Authorities also said Mateen legally purchased at least two firearms within the past week or so.

Security company G4S said in a statement to the Palm Beach Post that he had been an employee of the company since Sept. 10, 2007.

G4S released this statement: “We are deeply shocked by this tragic event. We can confirm that Omar Mateen had been employed by G4S since September 10, 2007. Mateen was off duty at the time of the incident. He was employed at a gated retirement community in South Florida. Mateen underwent company screening and background checks when he was recruited in 2007 and the check revealed nothing of concern. His screening was repeated in 2013 with no findings. We are cooperating fully with all law enforcement authorities including the FBI as they conduct their investigations. In 2013 we learned that Mateen had been questioned by the FBI but that the inquiries were subsequently closed. We were not made aware of any alleged connections between Mateen and terrorist activities and were unaware of any further FBI investigations. Our thoughts and prayers remain with the victims of this unspeakable tragedy and their friends and families.”

The FBI said agents twice investigated Mateen, but closed the cases after interviewing him.

FBI agent Ronald Hopper said Sunday that Mateen had been interviewed in 2013 and 2014.

Hopper said agents first investigated Mateen after he made inflammatory comments to co-workers alleging possible ties to terrorists.

Mateen was interviewed twice, and when investigators were unable to verify the details of his comments, the FBI closed the probe.

In 2014, the agency looked into potential ties connecting Mateen to Moner Mohammad Abusalha, the first American to carry out a suicide attack in Syria. Like Mateen, Abusalha lived in Fort Pierce.

Hopper said agents determined that contact was minimal and did not constitute a substantive relationship or a threat at that time.

The FBI said Mateen, 29, referred to the Islamic State in a 911 call before the slayings.

Mateen's father, Mir Seddique, said he's not sure why his son would have fired on a group of people,  but that he had become angry a couple of months ago when he saw two men kissing on a Miami street. 

“We are apologizing for the whole incident. We weren’t aware of any action he was taking. We are in shock, like the whole country,” Seddique told national news outlet.  

Seddique said he doesn’t believe the mass shooting had anything to do with religion. Police said Mateen was a U.S. citizen, born in New York City. 

Mateen was licensed as a private security officer in Florida, according to The Associated Press.

State records show Mateen held the firearms license since at least 2011. It was set to expire in September 2017. 

An armed guard license in Florida requires 28 hours of classroom training by a licensed instructor. 

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A woman who lives next door to the gunman told Channel 9’s Jamie Holmes that their nearby apartment was evacuated Sunday morning while the FBI entered Mateen’s home. 

The neighbor said Mateen lived in home with his wife and 4-year-old son, but officials have not confirmed that information.  

Gunman's home in Fort Pierce, officials say.
© 2017 Cox Media Group.

During a news conference Sunday, Sen. Bill Nelson said Mateen might have had “ties to terrorism.”

Authorities are asking anyone who knew Mateen to please come forward.  

Mateen was reportedly known to law enforcement, but was not the target of an investigation.

The Associated Press contributed to this report.