Omar Mateen 'visited Orlando's Pulse night club a dozen times', say regulars

It was also reported that the 29-year-old was seen at the Walt Disney World theme park

Omar Mateen, the disturbed 29-year-old who laid siege to a gay nightclub and killed 49 people, may have visited the venue up to a dozen times. He may have also been spotted at the nearby Walt Disney World park, triggering concerns he was possibly planning an attack on the holiday park.

As officials began to release the names of some of those who killed on Sunday and police said they were broadening their net in the hunt for clues, a report said that four regulars at the Pulse nightclub said they had seen the killer.

“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,” Ty Smith, who also uses the name Aries, told the Orlando Sentinel.

Mourners embrace during a candle-lit vigil, in memory of the victims of the gay nightclub mass shooting in Orlando, at St Anne's Church in the Soho (Reuters)

Mr Smith said he did not speak that much with the divorced security guard.

“We didn't really talk to him a lot, but I remember him saying things about his dad at times,” he added. “He told us he had a wife and child.”

It was also reported that Mateen, who lived in Fort Pierce, a two-hour drive from Orlando, had also seen at the Walt Disney World in April.

FBI Director James Comey said his agency was trying to nail down the veracity or otherwise of that report and the possibility that Mateen was scouting the amusement park as a potential target, the Associated Press said. “We're still working through that,” he said.

Mateen had been investigated over the period of ten months between 2013 and 2014 by law enforcement officials for possible links to Islamic extremists and yet the inquiries had proved inconclusive. As a result, the former state prison employee had no problem in buying two guns that he used with such lethal power in the early hours on Sunday morning when the club was packed with up to 300 people.

During the standoff, Mateen proclaimed his allegiance to Isis and his support for the Muslim brothers who set off two bombs at the 2013 Boston Marathon, police said.

He bought the weapons he used - a 9mm semiautomatic pistol and .223-calibre assault rifle - at St. Lucie Shooting Centre a few days before the massacre. Owner Edward Henson on Monday said he “vaguely” remembered him.

“He’s a nobody,” Mr Henson told the Sentinel. “He’s a customer. He came and purchased his guns, and he left.”

In 2006 Mateen worked at a state prison, the Martin Correctional Institution in Indiantown, for six months, according to Florida Department of Corrections. That same year, he earned a degree in criminal justice from Indian River Community College.

In 2007, he was hired by G4S, a private security firm based in the Florida city of Jupiter. His assignment at the time of his death: working as a security guard at a gated retirement community in South Florida, G4S said on Monday.