The Las Vegas gunman set up cameras inside and outside his hotel room before firing for at least nine minutes at a concert crowd below.

Police spoke of how Stephen Paddock carefully planned his actions before he opened fire on concertgoers at a "progressively rapid rate" through windows on the 32nd floor of the Mandalay Bay Hotel and Casino.

He placed one camera in a food service cart in the corridor, while a second camera was placed outside his room and a third in the peep hole of his two-room suite, officials said.

Details of the 64-year-old's meticulous planning emerged as Paddock's girlfriend, Philippines-born Marilou Danley, arrived back in the US on Wednesday for questioning.

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Investigators are examining a $100,000 (£75,340) wire transfer the killer sent to an account in the Philippines that "appears to have been intended" for Ms Danley.

The 62-year-old, who is an Australian citizen, remains among the "persons of interest" as police continue to grapple to find a motive for the deadliest mass shooting in modern US history - and whether anyone else was involved in the massacre of 59 people.

Ms Danley is said to have shared Paddock's apartment block at a retirement community in Mesquite, Nevada, about 90 miles (145km) northeast of Las Vegas, where police found 19 more guns after discovering 23 in his hotel room.

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Several pounds of ammonium nitrate, a chemical used to make explosives, were found in his car at the hotel.

Five handguns, two shotguns and a "plethora" of ammunition were discovered at another property that Paddock owned in Reno, Nevada.

Investigators who searched his hotel room also found a computer and 12 "bump stock" devices, which enable a rifle to fire continuously, like an automatic weapon.

Police said the shooting continued for 11 minutes, between 10.08pm and 10.19pm on Sunday.

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Paddock used at least 10 suitcases to smuggle the weapons into his room after checking in on Thursday last week.

Images posted by US media showed automatic weapons attached to tripods lying on the ground of the hotel room, with scores of bullet casings littering the floor around them.

At a news conference, Clark County Sheriff Joe Lombardo said: "The fact that he had the type of weaponry and amount of weaponry in that room, it was pre-planned extensively."

"Bump stock" devices are legal under US law, even though fully automatic weapons are for the most part banned.

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During his killing spree, Paddock shot a security guard who approached the room in the leg.

Patrol officers acting on their own and without the direction of a supervisor were the first to react to the situation and close in on Paddock's room.

The officers evacuated people from the 29th to 32nd floors before converging on the attacker's suite.

A SWAT team then used explosives to gain entry, where Paddock's body was found among his arsenal of weapons.

Police believe the retired accountant, a multi-millionaire who liked to gamble and invest in property, killed himself.

All but three of those who died have now been identified. More than 500 others were injured in the attack.