Omar Mateen: Everything we know so far about Orlando gunman
The man behind America’s worst-ever mass shooting was a New York-born US citizen of Afghan descent, who had pledged his allegiance to the Islamic State and was said to have been angered by the sight of two men kissing.
He then opened fire at a gay club in Orlando, killing 50 people and wounding 53.
Omar Mateen, 29, had worked since September 2007 as a security guard for G4S in Florida, a large security company which provided contractors to securing federal buildings.
G4S later said that Mateen would have carried a gun as part of his duties. A spokesman said it was thought he worked at a retirement home in south Florida.
"He was an armed security officer," said a spokesman, David Satterfield. G4S said in a statement that Mateen had been employed by the company since Sept. 10, 2007. He underwent background checks in both 2007 and 2013.
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Satterfield said G4S was trying to ascertain whether any guns used in the attack were related to Mateen's work.
"A lot of that is dependent on what law enforcement is releasing," he said.
He was thought to be living in the Port St Lucie area.
His ex-wife said he was "mentally unstable and mentally ill".
Sitora Yusifiy, speaking to reporters in Boulder, Colorado, said Omar 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 told the press that her family visited her and saw she was not OK and rescued her from the situation.
Ms Yusifiy says they literally pulled her out of his arms, adding that she left all her belongings and has had no contact with him for seven or eight years.
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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."
It's unclear when Mateen married his second wife, Noor Salman, but an August 30, 2013, property deed in Saint Lucie County identified them as a married couple. Family members said the pair had a young son who was about 3 years old.
He had a licence for concealed carry – in Florida, you do not require a permit to carry a weapon, but you do to conceal it. He also had a licence to work as a security guard. It was not clear when those permits were issued.
Mateen graduated with a degree in criminal-justice technology from Indian RiverCommunity College in 2006, the same year he changed his name from Omar Mir Seddique to Omar Mir Seddique Mateen, according to civil court records in St. Lucie County. The papers listed no reason for the name change.
CREDIT: ORLANDO POLICE
Mateen's wife told US law enforcement officers that she tried to stop her husband from carrying out his bloody attack on an Orlando gay club, it was reported by NBC News.
Noor Salman, 30, is said to have been with Mateen when he bought ammunition and a holster as he prepared for the attack that murdered 49 people.
She also drove him out to the club that he could scope it out, FBI sources familiar with the case told the television channel.
Salman may face charges for failing to warn authorities of the planned massacre, law enforcement officials said, but no final decision has been made. She is said to be cooperating with the investigation.
Mateen's second wife, Salman lived in a suburb of Chicago before moving to Fort Pierce’s with Mateen in November 2012, records show. But then in December 2015, she reportedly moved in with relatives in Rodeo, California.
She has not spoken publicly and has scrubbed her social media accounts since the attack. Her few remaining pictures show her smiling and posing with Mateen and a child believed to be their son. A photo from her Instagram shows Mateen kissing a child, under the title, “daddys boy".
Known to police
He was known to the police, having become “a person of interest” in 2013 and again in 2014.
A senior law enforcement source told The Daily Beast that 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 called 911, while holding hostages inside, to pledge allegiance to the Islamic State of Iraq and the Levant (Isil). He also reportedly also mentioned the Boston marathon bombers.
However, no direct links with IslmicState have been discovered. Mateen had expressed support for multiple armed Islamist movements and people, which "adds a little bit to the confusion about his motives," FBI Director James Comey said.
"So far, we see no indication that this was a plot directed from outside the United States and we see no indication that he was part of any kind of network," Mr Comey said in Washington. "We're highly confident this killer was radicalised at least in some part through the internet."
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The gay club was deliberately chosen, his father Mir Seddique suggested.
He told NBC News that the sight of two men kissing angered his son.
“We are saying we are apologising for the whole incident,” the father added. “We weren’t aware of any action he is taking. We are in shock like the whole country.”
The attack, he said, “has nothing to do with religion.”
Patrons have said they saw Mateen drinking at the bar several times before the shooting. Ty Smith told The Orlando Sentinel he saw Mateen inside at least a dozen times.
"Sometimes he would go over in the corner and sit and drink by himself, and other times he would get so drunk he was loud and belligerent," Mr Smith said.
Mateen is also said to have used a gay dating app. Kevin West, a regular at Pulse nightclub, said Mateen messaged him on and off for a year before the shooting using the gay chat and dating app Jack’d, according to the LA Times. Cord Cedeno also said he saw him on it, the Washington Post reported. “He was open with his picture on the sites, he was easy to recognise,” said Mr Cedeno, 23, of Orlando, who said he was also contacted by Mateen at least a year ago on a dating app.
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Syed Ur Rahman, the imam of the mosque where Mateen prayed four days a week, told The Daily Telegraph he had known the gunman since he was a child.
Mateen was a wild boy, and an imposing young man, but Mr Rahman said he had changed in recent years.
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While Mr Rahman had heard "rumours that he was aggressive", the muscular Mateen prayed with his young son without ever exchanging a word with anyone.
Despite the fact that another young man who had visited the mosque on occasion became a suicide bomber in Syria, Mr Rahman said the teaching at the mosque was peaceful and moderate.
However, the British born Islamic preacher, Sheikh Farrokh Sekaleshfar, gave a speech just outside Orlando in March in which he called for the death of all homosexuals.
“Death is the sentence. There’s nothing to be embarrassed about this. Death is the sentence,” he said. It was not clear whether Mateen attended.