Stephen Paddock, 64-year-old wealthy former accountant and high-stakes gambler has been identified by police as the man behind the deadliest mass shooting in modern United States history when he opened fire from the Mandalay By Hotel and Casino on October 1, killing 58 people and injuring almost 500 others, before turning the gun on himself as police closed in. The assault killed 58 people and injured more than 500 in the deadliest mass shooting in recent USA history.
"We are trying to prove his intent or understand his intent and the history associated with this and whether or not he has any accomplices", Lombardo said.
The bloodshed might have lasted longer, with greater loss of life, but for a hotel security officer who was sent to check an open-door alarm on the 32nd floor, and discovered the gunman's whereabouts after the shooting started, McMahill said.
Paddock shot the guard at 9:59pm (local time), Sheriff Lombardo said, shortly before raining down bullets on the Route 91 Harvest festival in an attack that began at 10:05pm and lasted 10 minutes.
The FBI has brought in specialist profilers as they continue questioning Paddock's live-in girlfriend, Marilou Danley, about his gun purchases and what she may have noticed about his behaviour, Mr Lombardo said.
Charles "Sid" Heal, a retired Los Angeles County sheriff's commander and tactical expert, said the new timeline "changes the whole perspective of the shooting".
"We do not believe there is one particular event in the suspect's life for us to key on", he said.
That raises questions about what the killer had been planning before Campos disturbed him, and why police did not arrive sooner.
But so far, authorities looking to see if anyone may have aided Paddock found no evidence of the gunman having associates in Las Vegas.
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In footage shared on social media, police officers could be seen pinning a man on the ground in the aftermath of the incident. The Metropolitan Police said the man had been arrested at the scene and initially received hospital treatment.
Investigators believe a note found in the Las Vegas shooter's hotel room contained a series of numbers that helped him calculate more precise shots.
Unlike so many other perpetrators of deadly mass shootings before him, Paddock left behind no suicide note, no manifesto, no recordings and no messages on social media pointing to his intent, according to police. Lombardo also says Paddock fired at fuel tanks near the Mandalay Bay Hotel, perhaps to create a diversion.
The SWAT officer used a pry bar to pop the door open, Newton said.
"While some of it has helped to create a better profile into the madness of this suspect, we do not, still, have a clear motive or reason why", said McMahill.
At the Cosmopolitan, he said he had opened a bottle of sake in his room, possibly on the night of the incident, but did not drink much.
"He's like on retainer, I call it, I guess", Paddock said, according to CNN.
There is still no evidence Paddock was motivated by ideology, or that there was another shooter, he said. Paddock's wardrobe did not bespeak of a man of wealth, said the broker, who asked not to be identified discussing the gunman. He checked into a hotel room overlooking the music festival, stocked a cache of weapons there and set up cameras inside his hotel suite and hallway.
Since the October 1 massacre, while Paddock's motive has baffled investigators, a picture of his life has taken shape. Paddock killed himself before police entered his room.
"I could see on it he had written the distance, the elevation he was on, the drop of what his bullet was going to be for the crowd", Newton said.
"A week into this, a lot of people have been numb", said Red Cross spokesman Bill Fortune, who flew in from Colorado to help with the recovery effort.