"Right now, we believe it's a sole actor, a lone-wolf-type actor", said Lombardo.

Authorities have not yet determined a motive for his actions. About 22,000 people were in attendance at the time of the shooting. He opened fire as the artist Jason Aldean performed. Still, DHS security may be heightened in and around public places and events, DHS said.

ISIS did claim responsibility for the attack, but officials have found no connections between the terrorist group and Paddock.

Stephen Paddock's brother Eric told CNN their father died years ago and "was never with my mom".

His brother Eric insisted he was just a normal "guy", adding that he must have "snapped".

Neighbours immediately next to Paddock's mustard-coloured home displayed a sign on their door: "We did not know him".

Authorities at the time said Benjamin was a diagnosed psychopath and therefore, "extremely risky".

Paddock had been wanted for escaping from a federal prison in Anthony, Texas, after he was convicted of a string of armed bank robberies in Arizona. The elder Paddock tried to run down an FBI agent in Las Vegas in 1960 and wound up on the agency's most wanted list after escaping from a federal prison in Texas in 1968. He was again arrested in 1978 but got out on parole; he remained a free man until 1987, when he was indicted on seven racketeering charges in Oregon. He displayed no strong religious or political views, his relatives said, and was not known for angry outbursts.

Eric Paddock told CBS News that he knew Paddock had handguns but that as far as he knew, Paddock did not own "machine guns".

Relatives, living in central Florida, said they have no clue what could have led up to the mass shooting. He had a pilot's license and had owned two single-engine planes. "There's no rationale. There's nothing anywhere that said why he did this".

Court records show Paddock was married in 1977 - their divorce was finalised in 1980 in Los Angeles County. Among the dead, was an unidentified Las Vegas Metropolitan Police Department officer, who was off-duty at the time. "That is a matter for continued investigation". The community includes an 18-hole golf course, indoor and outdoor swimming pools and a recreation center.

The 64-year-old travelled to Las Vegas several days before the shooting, setting up his stay at the Mandalay Bay Hotel located in the heart of the famous strip.

Ten years later, Benjamin Paddock was located by police in OR, according to a 1978 report in the Arizona Republic.

Lockheed Martin said in a statement that Paddock worked for a predecessor company of Lockheed Martin from 1985 to 1988.

And according to one, Paddock appeared "rude" when he ordered a Mocha Frappucino for Danley, instead of letting her order for herself. "What a bad tragedy for the children", she said.

The mangled remains of Paddock's garage door sat in his driveway, after authorities searched the home on Monday.