Stephen Paddockshot a security guard before opening fire on concertgoers in Las Vegas last weekend, Clark County Sheriff Joseph Lombardo said. The guard was investigating an alarm signaling that a door had been left open on the same floor as Paddock's room.
Paddock shot Jesus Camposin the leg, injuring him at 9:59 p.m. on October 1, according to Lombardo.
At 10:05 p.m, Paddock shot numerous rounds into the crowd at the Route 91 Harvest Festival from his room on the 32nd floor of the Mandalay Bay Resort and Casino, authorities have said. He continued firing for about nine to 11 minutes.
Paddock's final shots were fired at 10:15 p.m., according to a police timeline. Authorities do not yet know what made him stop shooting, Lombardo said. By the time officers entered the room, Paddock was dead from a self-inflicted gun shot wound.
The detail reflects a change in the shooting timeline police had earlier provided. Authorities had previously said they believed Campos drew Paddock's attention away from firing out the window, and that Paddock didn't fire any further shots after wounding the guard.
"What we have learned is Mr. Campos was encountered by the suspect prior to his shooting to the outside world," Lombardo said.
Investigators are still piecing together evidence left behind in the hotel room and probing Paddock's background to determine why the retired accountant committed the worst mass shooting in modern US history.
Lombardo said police have found "no evidence to show that there was a second shooter."