WASHINGTON - The head of the US Senate Intelligence Committee said Wednesday there was no apparent "terrorism nexus" in the Las Vegas mass shooting and a top FBI official said the motive has proved elusive so far.
Senator Richard Burr, who as the committee's chairman is a congressional overseer of the US intelligence community, did not elaborate but his comment echoed those of the Federal Bureau of Investigation.
"At this point I'm glad to say that it doesn't seem to have a terrorism nexus," Burr told reporters.
The Islamic State group has claimed that the shooter, Stephen Paddock, was a "soldier" who had recently converted to Islam.
US authorities have expressed scepticism about the claim. FBI special agent in charge in Las Vegas, Aaron Rouse, said investigators had found no evidence of a link.
And the deputy director of the FBI, Andrew McCabe, told CNBC television Wednesday that the motivation for Sunday night's deadly shooting spree has not yet been determined.
"This one is somewhat different than many of the ones that we've dealt with in the past because we don't have any immediately accessible thumbprints that would indicate the shooter's ideology or motivation or, really, what compelled him to get there," McCabe said.
"That is, of course, what we are focused on," McCabe told the television outlet on the sidelines of the Cambridge Cyber Summit. "We're doing a lot of work in Las Vegas and many other places to get to the bottom of that."
McCabe said he was not "completely surprised" that it has taken this long to figure out the shooter's motive.
"This is an individual who was not on our radar, or anyone's radar, prior to the event," he said. "So we really have a challenging bit of detective work here to kind of put the pieces back together after the fact.
"It's the quieter and harder work that we have to do now in terms of identifying people who may have known him, who may have seen him, who crossed paths with him in the days and weeks leading up to the event and that's where we're focused right now," he said.
Paddock, a 64-year-old retired accountant who gambled heavily, opened fire Sunday night from his 32nd-floor hotel room on the crowd at a country music festival across the street.
Fifty-eight people were killed and more than 500 injured in the deadliest mass shooting in recent US history.
Police who burst into Paddock's room found that he had killed himself.