Watch: New Body-cam vision shows cops raiding room after room as gunman rained bullets down on music festival

Some of the first officers to reach the Las Vegas hotel room where a gunman unleashed the deadliest mass shooting in modern US history busted in with shields and found his body and assault-style weapons scattered around, according to police body-camera video released Wednesday (Thursday NZT).

Hours of footage from two officers' body-worn cameras show police walking into a casino that was still packed after gunfire started raining down on an outdoor concert from 32 floors up in a Las Vegas Strip casino-hotel.

People were still playing slot machines as an officer told an employee: "There's a shooter. He's shot and killed multiple people already." Police ordered people to flee and told a worker: "Get everyone out of here."

Police say Stephen Paddock killed 58 people and injured hundreds more from the windows of his hotel suite last fall before killing himself as authorities closed in.

The videos do not provide a complete view of everything police discovered when they entered Paddock's suite or any clues about why he opened fire October 1 (October 2 NZT)

The footage shows officers checking rooms in the Mandalay Bay before getting to Paddock's room. An officer says, "Breach! Breach! Breach!" before a loud bang and a fire alarm begins to sound.

Inside, Paddock's body is seen his back, clad in dark pants and a long-sleeve shirt with a glove on his left hand. An apparent pool of blood stains the carpet near his head as a police SWAT officer walks past.

An officer grabs an assault-style rifle from the ledge of a broken window and other weapons are found around the room.

The videos record officers talking about whether there is evidence of a second shooter and finding Paddock's driver's license. Police and the FBI later said they believe the 64-year-old former accountant and high-stakes video poker player acted alone.

The videos do not show what the first officer through the door saw because he didn't activate his body-worn camera. The disclosure by police lawyers late Tuesday raised questions about whether officers followed department policy.