Pictured: Las Vegas gunman behind the 'worst shooting in US history'

The man behind the worst mass shooting in US history has been identified as a retired accountant who had no known history of violence until he shot dead 59 people in a hail of gunfire from his Las Vegas hotel window.

Stephen Craig Paddock left the world and his family in shock after the 64-year-old sowed terror on the Vegas strip, killing dozens and injuring a further 527 people at a country music festival.

Concertgoers never stood a chance when Paddock perched himself out the window of the 32nd floor inside the Mandalay Bay Hotel with at least ten high powered weapons at his disposal.

Paddock was found dead, reportedly from a self-inflicted gunshot wound, when a police SWAT team burst in to his room on the 32nd floor of the Mandalay Hotel.

Stephen Craig Paddock has been identified as the shooter who gunned down at least 59 people. Source: 7 News

The shooter was found dead inside his hotel room. Source: 7 News

His brother, Eric Paddock, told CBS News his brother was "not an avid gun guy at all."

"Where the hell did he get automatic weapons? He has no military background or anything like that," he said.

"He's a guy who lived in a house in Mesquite, drove down and gambled in Las Vegas. He did stuff. Eat burritos."

The gunman, who photographs showed as greying with a trimmed beard and moustache, was a former accountant and a licensed pilot with no criminal record, according to ABC News.

Terrified festivalgoers duck for cover as gunfired hails down. Source: Getty Images

Former Gold Coast resident Marilou Danley is believed to be the partner of the deceased Las Vegas gunman. Source: Twitter/@LVPD

IS's propaganda outlet Amaq said in online statements the attack was carried out by a "soldier" who had "converted to Islam several months ago".

However security officials said Paddock appeared to have been working alone, and his brother told US media he had no known religious affiliation.

"Nothing. No religious affiliation, no political affiliation, he just hung out," Eric Paddock told CBS.

The 55-year-old Paddock, who lives in Orlando Florida, told media the family was shocked by the shooting.

Festival goers near the scene. Source: Getty Images

A man in a wheelchair is taken away from the scene. Source: Getty Images

"It's like an asteroid just fell on top of our family," he told the Las Vegas Review-Journal. "We have no idea how this happened."

Stephen Paddock also had a hunting license for Alaska, where hunting for big game like elk and bear is popular.

According to publicly available information, he resided in a new golf course development carved into the desert just outside Mesquite, Nevada on the border with Arizona.