Las Vegas police have confirmed Paddock shot a hotel security guard at 9.59pm, before firing into the crowd below at 10.05pm.
The account is significantly different to the sequence of events presented last week, which alleged Paddock shot the guard, Jesus Campos, after shooting into the crowd.
The guard had been in the hallway responding to another call when he was shot, the Washington Post reported.
Paddock killed 58 people after opening fire on the large crowd at the Route 91 Harvest country music festival from the 32nd floor of the Mandalay Hotel last week.
As investigators continue to search for a motive into the tragedy, Las Vegas Sheriff Joseph Lombardo revised the chronology of the shooting.
The chief of the Las Vegas Metropolitan Police Department confirmed Mr Campos was shot as Paddock strafed a hallway with 200 rounds before taking aim at the crowd below.
Mr Campos is now recovering from his injuries.
“What we have learned is Mr Campos was encountered by the suspect prior to his shooting to the outside world,” the Sheriff said.
The timeline change comes as the FBI claimed the sheriff had been providing inaccurate information for several days about the attack, ABC News reported.
Inside shooter Stephen Paddock’s room at Mandalay Bay hotel, Las Vegas. Picture: SuppliedSource:Supplied
One former FBI agent Brad Garrett said this was a significant development and raised the question as to whether the shooter could have been stopped in that crucial six minute period.
“And those six minutes, you may not have been able to get the police there, but you may have been able to create a disruption of some sort that would have kept him from doing what he ultimately did,” Mr Garrett told ABC News.
CRUCIAL SIX MINUTES
Chad Pinkerton, a lawyer for Paige Gasper, a California college student who was shot under the arm in the attack told the Associated Press the victims deserved answers.
“These people that were killed and injured deserve to have those six minutes to protect them,” Mr Pinkerton said.
“We lost those six minutes.”
However Ron Hosko, a former FBI assistant director who has worked on SWAT teams, said the attack could not have been stopped in that short amount of time.
Mr Hosko said police would have been formulating the best response to the barricaded gunman rather than rushing in without a game plan.
“Maybe that’s enough time to get the first patrolman onto the floor but the first patrolman is not going to go knock on that customer’s door and say ‘What’s going on with 200 holes in the door?”’ Mr Hosko said.
Peter Blair, a criminal justice professor and executive director of the Advanced Law Enforcement Rapid Response Training Center at Texas State University told the Washington Post confusion is common in mass shooting events.
“Once they determine an active shooting is going on, the first priority is to stop the killing,” he said.
“The longer delay there is in finding that person, the more time that person has to operate, to shoot people, to cause damage and chaos. So it’s important to keep that window as small as possible.”
Paddock smashed two windows in his hotel suite which enabled him to fire on the crowd below. Picture: Robyn Beck/AFPSource:AFP
SECOND CALL FOR HELP
Mr Campos wasn’t the only hotel worker who reported the shooting.
Maintenance worker Stephen Schuck told NBC News that he was checking out a report of a jammed fire door on the 32nd floor when he heard gunshots.
He said the hotel security guard who had been shot in the leg peeked out from an alcove and told him to take cover.
“It was kind of relentless so I called over the radio what was going on,” Mr Schuck said.
“As soon as the shooting stopped we made our way down the hallway and took cover again and then the shooting started again.”
Mr Schuck used his radio to report the shooting, telling a dispatcher: “Call the police, someone’s firing a gun up here. Someone’s firing a rifle on the 32nd floor down the hallway.”
Mr Campos also used his radio and possibly a hallway phone to call hotel dispatchers for help, police said.
It remains unclear if and when the hotel relayed the reports of shots being fired to police.
MGM Resorts, which owns the hotel, disputed Las Vegas police timeline of shooting.
In a statement to Fox News, MGM International spokeswoman Debra DeShong stressed a lot of information had not yet been confirmed.
“This remains an ongoing investigation with a lot of moving parts,” she said.
“As evidenced by law enforcement briefings over the past week, many facts are still unverified and continue to change as events are under review.
“We cannot be certain about the most recent timeline that has been communicated publicly, and we believe what is currently being expressed may not be accurate.”
Members of the University of Las Vegas prom squad visit 58 white crosses for the victims of the shooting. Picture: Robyn Beck/AFPSource:AFP
It also emerged Paddock may have used a hotel service elevator reserved for high rollers in the lead up to the deadly shooting.
Officials have told US broadcaster ABC News that Paddock may have used the elevator to smuggle his 23 powerful weapons into his room on the 32nd floor of the Mandalay Hotel.
It remains unclear how Paddock managed to keep so many weapons into the hotel without staff noticing.
Last week former Las Vegas Metropolitan Police Department officer Randy Sutton told CBS This Morning Paddock would not have brought all his firepower up to his room in just one trip.
Sutton said Paddock had been staying in the room for three days and probably used a golf bag or luggage to bring it all up.
Meanwhile ABC News reported the gunman’s Australian-Filipina girlfriend, Marilou Danley, has been put on a US government watch list that will notify authorities if she attempts to leave the country on a commercial airline flight.
Ms Danley has been designated a Transportation Security Administration selectee as the FBI continues to interview for any potential information about the shooting.
Authorities believe Ms Danley, who is continuing to co-operate with authorities, did not play a role or know about her boyfriend’s plans.
— with the Associated Press