Despite 1,000 leads, motive behind Las Vegas shooting 'still not clear'

The motive behind the Las Vegas gunman's attack still remains a mystery, officials have admitted.

At a press conference, Las Vegas police undersheriff Kevin McMahill said they had chased down more than 1,000 leads in the days since Stephen Paddock opened fire on the Route 91 Harvest Festival on Sunday night.

But in the absence of a note, a social media post, or other evidence, he said there was still "no clear motive".

"I get it - we all want answers," he said.

"We have been down each and every single one of these paths, trying to determine why."

He went on to urge people not to engage in speculation online and on social media, saying it had been "unhelpful" as it had presented a niumber of false leads which officers had been obliged to waste time chasing down.

He encouraged anyone with solid factual evidence to come forward, but asked those without it to reconsider, adding: "Just because you think you know something, doesn't mean you do."

He said officers were "confident" there was no second shooter in the room with Paddock, but said they were still investigating whether there may have been someone else who knew about the shooting in advance.

He said detectives were looking at "every aspect" of the gunman's life, from birth to death, in response to a question asking whether there was a potential "obsession" to the month of October - as he bought his guns in October last year, and had his lawsuit against the Cosmopolitan of Las Vegas casino and resort dismissed in October 2014.