Documentary Footage Shows Omar Mateen In 2010

Footage has emerged showing Omar Mateen working as a security guard in 2010, six years before he shot dead 49 people at an Orlando nightclub.

The 29-year-old is seen on duty as a guard during the clean-up operation following the Deepwater Horizon oil spill in the Gulf of Mexico.

The footage appears in the 2012 award-winning documentary The Big Fix, and shows Mateen speaking with a reporter while contracted to the security company G4S.

It comes as authorities continue to investigate the motive of Sunday's attack, which also wounded 53 people.

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Mateen's wife Noor Salman is being questioned by the FBI and authorities are also investigating whether the American-born gunman was living a secret life as a gay man.

An official told the Associated Press investigators believe Ms Salman knew about the plot to attack Orlando's Pulse nightclub in advance.

At a Wednesday afternoon news conference, US prosecutor Lee Bentley would not speculate on what charges might be brought in the investigation.

But he said threats had been made against the local Muslim community, and he warned such intimidation would not be tolerated by the authorities.

The FBI is also looking into reports from patrons of the club who claim Mateen was a regular at the venue and also used gay dating apps.

Jim Van Horn, 71, said he saw Mateen multiple times at the venue's bar and talked to him once.

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"He was a homosexual and he was trying to pick up men," Mr Van Horn said.

"He would walk up to them and then he would maybe put his arm around them or something and maybe try to get them to dance a little bit or something."

One club regular, Ty Smith, told The Orlando Sentinel newspaper he had seen Mateen at least a dozen times.

He said: "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.

"We didn't really talk to him a lot, but I remember him saying things about his dad at times," Mr Smith added.

"He told us he had a wife and child."

Some have suggested Mateen's familiarity with the club may explain why he chose Pulse, rather than other clubs closer to his home in Port St Lucie, about 130 miles (200km) south of Orlando.