How the Las Vegas mass shooting investigation is unfolding

Stephen Paddock of Mesquite, Nev., checks in to the Mandalay Bay Resort and Casino on Sept. 25. Paddock is an accountant and licensed pilot who appears to have had no previous run-ins with the law. Authorities believe Paddock checked into the hotel using the ID of a woman named Marilou Danley, whom police describe as a person of interest.

At 9:59 p.m. on Oct. 1A hotel security guard is shot by Paddock on the 32nd floor, according to a revised police timeline. The wounded guard called hotel officials to warn them about the gunman.

The suspect starts shooting fire at 10:05 p.m. on Oct. 1, according to closed-circuit television from the concert venue. Shots were fired during singer Jason Aldean's performance, the last scheduled act on the main stage of Route 91 Harvest country music festival. Police say the shooting lasted at least nine minutes.

Police said Paddock smashed the windows with a hammer-like tool before opening fire.

By 10:12 p.m. two officeres arrive on the 31st floor and announce the gunfire is coming from directly above them. The last shots are fired from the suspect at 10:15 p.m., according to body cameras. The two officers arrive on the 32nd floor at 10:17 p.m.. A minute later, the security officer tells police he was shot and gives location of the gunman's room.

Eight officers arrive on the 32nd floor and begin to move systematically down the hallway, clearing every room and looking for any injured people from 10:26-10:30 p.m.

Eight more officers arrive in the stairwell at the opposite end of the hallway nearest to the suspect's room at 10:55 p.m.

The first breach is set off and officers enter the room at 11:20 p.m. They observe the suspect down on the ground and also see a second door that could not be accessed from their position.

The second breach is set off at 11:27 p.m., allowing officers to access the second room. Officers quickly realize there is no one else in the rooms and announce over the radio that the suspect is down.

At least 23 firearms were found inside the shooter's room. Authorities have identified four Daniel Defense DDM4 rifles, three FN-15s and other rifles made by Sig Sauer. Paddock apparently bought the guns legally, passing the required background checks.

At least twelve rifles in Paddock's hotel room had been modified with a legal “bump stock” style device, according to an official from the Bureau of Alcohol, Tobacco and Firearms and Explosives (ATF). This allows the shooter to rapidly fire off rounds without actually converting the rifle into a fully automatic weapon, according to a law enforcement source. These devices are legal in the U.S.

Portions of the Strip were closed following the shooting. Hotel guests blocked from returning to their hotels were shuttled to a center equipped with metal detectors.

Two members of the FBI in Reno arrived at Stephen Paddock's house in Reno's Somersett neighborhood on Oct. 2 around 9:30 a.m. Agents went through the home and found five handguns and two shotguns. The agency has ruled out any connection with ISIS terrorism activities.

Investigators also discovered 19 firearms, thousands of rounds of ammunition as well as explosives at Paddock’s home in Mesquite, Nevada.

Currently, 47 firearms have been identified between the hotel suite and two of Paddock's residences in Mesquite and Verdi, Nev., according to Jill Snyder, special agent in charge of the San Francisco ATF bureau. The firearms were purchased from Nevada, Utah, California and Texas, Snyder said.

Common public space cameras as well as 67 body camera videos are being evaluated, Las Vegas Metro Police Department sheriff Joe Lombardo said in an Oct. 3 conference.

Marilou Danley, the girlfriend of the gunman, returned Tuesday night to the United States from the Philippines, according to multiple law enforcement sources. She was met by federal agents at Los Angeles International Airport and is expected to be interviewed by investigators at the FBI Los Angeles headquarters, an official said.

Authorities have her as a "person of interest" and hope talking with her would shed light on why Paddock carried out the rampage.

On Wednesday, she released a statement, saying she had no idea Paddock was planning a mass shooting. She added: “I loved him and hoped for a quiet future together with him.”

Paddock also researched outdoor performance areas in Boston and other large cities months prior to the Las Vegas shooting, a law enforcement official with knowledge of the investigation said Thursday.

Since the shooting, a clearer picture of who the victims were has been reported. Of the 58 victims, 36 were women and 22 men. They worked in schools, police departments and family businesses across America and Canada. More than half came from California.