Motive for Las Vegas gun massacre remains unclear

The motive behind the Las Vegas gun massacre remains unclear as the United States attempts to come to terms with the deadliest mass shooting in its modern history.

Investigators are working to understand what may have driven Stephen Paddock, 64, to open fire on crowds at a music festival from the 32nd floor of the Mandalay Bay Hotel.

The assailant’s brother, Eric Paddock, said he was a “top player” and described gambling as “like a job for him”.

“He was at the hotel for four months one time. It was like a second home,” he told reporters.

Whether the gunman was a regular at the Mandalay Bay or had a troubled relationship with the city may be a line of inquiry pursued by authorities.

In the weeks running up to the attack, Paddock had spent tens of thousands of dollars in the strip’s casinos, NBC News reported.

On several occasions he gambled more than 10,000 US dollars (£7,500) per day and in some cases more than 20,000 (£15,000) and 30,000 dollars (£22,500), police sources told the US broadcaster.

It was not clear whether he had won or lost money during his betting sessions, the report added.

Suggestions that the attacker had run up huge debts were dismissed by his brother, and public records also show no evidence of financial problems.

He said: “He had substantial wealth. He’d tell me when he’d win. He’d grouse when he’d lost. He never said he’d lost four million dollars or something. I think he would have told me.”

The gunman was not known to authorities, but early evidence suggests the attack was meticulously planned to inflict heavy casualties.

The FBI said it had found “no connection with an international terrorist group” after Islamic State rushed to claim responsibility for the massacre.

Investigators believe Paddock was a “lone wolf” attacker, but his family – who say he had no political or religious affiliations – are at a loss to explain what led him to plan and carry out the shooting.

Paddock armed himself with as many as 23 firearms, including several designed to fire at long-range, and some which may have been modified to fire automatically.

He arrived at the Mandalay Bay Hotel and Casino four days before the attack with at least 10 suitcases filled with guns, according to police.

His room’s position on the upper floors provided a clear shot at the crowds below, and officials are exploring the possibility he used tripods to fire more accurately, the New York Times reported.

While some officials have suggested the gunman had a history of psychological issues, this has not been confirmed.

When asked about the gunman’s motive, Sheriff Joseph Lombardo said he could not “get into the mind of a psychopath at this point”.