Sheriff Joe Lombardo of the Las Vegas Metropolitan Police Department said that in the "spirit of safety" for the community and elsewhere in the United States, he doesn't have a solid answer at the moment regarding motive, but reports he is "pretty confident we'll get there". "Trying to determine who else may have known of these plans", McMahill said, adding that the rumors and speculation that have abounded in the wake of the shooting have been unhelpful to their investigation. "We will not stop until we have the truth".
Investigators had reviewed voluminous video from the casino and don't think Paddock had an accomplice in the shooting, McMahill said.
The official pledged that law enforcement would work with "great tenacity" to uncover the reasons why Paddock carried out the massacre. The official wasn't authorized to discuss the matter publicly and spoke to The Associated Press on condition of anonymity.
The attacker, identified as 64-year-old Stephen Paddock, of Mesquite, broke two windows on the 32nd floor of Mandalay Bay and unleashed a 10-minute barrage of bullets at the Route 91 Harvest music festival across the street.
The official said investigators were interviewing other call girls for information and looking into at least a dozen cruises Paddock took in the last few years, including one to the Middle East. Why do we care so much about the motives of mass shooters?
"It's extremely hard", said Erroll Southers, the director of homegrown violent extremism studies at the University of Southern California. "We're so used to, in the first 24 to 48 hours, being able to review social media posts".
Just how Paddock amassed such a large collection of high-powered weaponry is simple: There's no limit on how many weapons people can own, as long as they pass background checks.
In all, authorities have found 47 guns of varying size and power that belonged to Paddock. He requested an upper-floor room overlooking the festival, stockpiled 23 guns, a dozen of them modified to fire continuously like an automatic weapon, and set up cameras inside and outside his room to watch for approaching officers. Tracer ammunition means bullets with a pyrotechnic charge which leaves an illuminated trace of its path after being fired.
Disputing a media report published Friday, McMahill also said investigators "do not believe" someone used a key card to enter Paddock's room during a period when his auto was not in the Mandalay Bay garage.
Investigators are also having trouble tracing bump stocks, because they do not have serial numbers that allow them to track when the devices change hands.
McMahill said investigators are looking into Paddock's mental health and any medications he was on.
Paddock sent Danley on a trip to her native Philippines before the attack, and she was unaware of his plans and devastated when she learned of the carnage while overseas, she said in a statement.
Stone, who wrote the book The Anatomy of Evil, which explores the mindsets of some of the most prominent killers of our time, said there's a "fascination" with such people like Paddock.
"You don't have any cases of leakage - no one to say who's he mad at, what his motive is", Southers said.