Islamic State has claimed responsibility for the shooting in Las Vegas on Sunday night which left 59 people dead and over 500 injured. US officials have said, however, that there is no established link between the shooter, Stephen Paddock, and any terrorist organisation.

ISIL claimed that Paddock, 64, converted to Islam a few months ago, and that, in carrying out the shooting, he acted as a 'soldier' of the caliphate responding 'to calls to target coalition countries'.

It also claimed through its official Amaq news channel that Paddock went by the name Abu Abd al-Barr al-Amriki and was heeding a call to arms by ISIL's leader Abu Bakr al-Baghdadi. In an audio message released last Thursday, Baghdadi commanded his followers to 'besiege [the West] in every corner'.

Police say that Paddock killed himself after the shooting. Although Paddock, a retired accountant, is thought to have a history of psychological disturbance, he has never faced any significant criminal charges.

'There's absolutely no way I could conceive that my brother would shoot a bunch of people he doesn't even know', Eric Paddock, the shooter's brother, told CNN reporters. 'Steve had nothing to do with any political organisation, any religious organisation, no white supremacist group, nothing', he continued.

Paddock's father, Benjamin Hoskins Paddock was on its most-wanted list from June 10, 1969 until May 5, 1977. But Eric Paddock claimed that they never had contact with their father and he resisted the idea that Stephen had been seeking to follow in his father's footsteps.

According to Eric Paddock and people who lived near to Stephen Paddock, he enjoyed gambling and going on cruises, was a successful property estate investor and had a pilot's licence. He had been married and divorced twice, and was living with his girlfriend, Marilou Danley, who is not believed to have been involved.

Police have recovered 42 firearms: 23 in the his hotel room and 19 at his home in a retirement village in Mesquite, Nevada. Several thousand rounds of ammunition were also found and Paddock's car contained several pounds of ammonium nitrate, a material used to make explosives.

Investigators believe the firearms were purchased legally. A shop in Mesquite, Guns & Guitars, told CNN it had sold a gun to Paddock and that 'he never gave any indication or reason to believe he was unstable or unfit at any time'. 

'If there was any impression, I would say, guy had no idea what a gun was' said Don Judy, who lived next door to Paddock between 2013 and 2015 in Melbourne, Florida.

'He's not an avid gun guy at all. The fact that he had those kind of weapons is just – where the hell did he get automatic weapons? He has no military background or anything like that', Eric Paddock told MSNBC.

He described receiving the news that his brother was responsible for the shooting as 'like if an asteroid fell out of the sky'.