LAS VEGAS -- Every detail seemed meticulously planned.
The selection of a hotel room overlooking a music festival, days before the attack.
The cache of 23 weapons inside the gunman's Las Vegas suite.
And thousands of rounds of ammunition -- plus an ingredient used in explosives -- inside the killer's home and car.
The latest revelation came Tuesday afternoon when police said gunman Stephen Paddock set up cameras inside his hotel suite and in the hallway.
Police are not aware whether the devices were transmitting -- the FBI is investigating their use -- but the Clark County sheriff told reporters he thinks the shooter might have used them to watch for people approaching his room.
One camera looked out the peephole on the suite's door.
The Bureau of Alcohol, Tobacco, Firearms and Explosives disclosed that Paddock had outfitted 12 of his rifles with a legal device called a bump-fire stock, which enables a shooter to fire bullets rapidly, similar to an automatic rifle.
Authorities released the first body camera footage of police responding to the shooting. It captured the rapid staccato of the gunfire at a fairly close range.
Officers were seen hunkering down behind a wall.
"Go that way, get out of here. There's gunshots coming from over there," one officer is heard yelling at civilians.
At one point, they were next to a patrol vehicle on Las Vegas Boulevard, where one officer was shot, undersheriff Kevin McMahill said.
No one knows why Paddock morphed from a retired accountant to the deadliest mass shooter in modern U.S. history.
His relentless gunfire -- police say he fired for nine to 11 minutes after the first 911 call -- on country music fans at an outdoor concert left 58 people dead.
Another 500 people are still trying to recover from injuries -- everything from gunshot wounds to stampede injuries suffered when 22,000 people tried to flee the gunman's aim.
So far, police believe Paddock acted alone -- which could make the motive harder to determine.
Clark County Coroner John Fudenberg said 58 people were killed. Authorities had previously said 59 were killed in the shooting, but on Tuesday clarified that number included the shooter.
The Daily Mail newspaper of the U.K. has published several photos taken in Paddock's room after the shooting.
In one photo, the legs of a dead shooter can be seen on the floor. The photos show semiautomatic assault-style rifles on the floor and on furniture. Stacks of ammunition magazines used in rifles can also be seen.
Paddock wired $100,000 to the Philippines, a law enforcement source said. However, officials haven't been able to see precisely when the wire happened or who was the recipient. The FBI is working with Filipino authorities to determine details.
Five handguns, two shotguns and a "plethora" of ammunition were found in Paddock's Verdi, Nevada, property, police said.
Authorities previously found 42 guns in Paddock's hotel room and at his Mesquite, Nevada, home.