Vegas Gunman Shot Guard Before Firing on Crowd

Law enforcement authorities are making a significant change to the timeline of the Las Vegas mass shooting, saying the gunman shot a hotel security guard before he opened fire on concert-goers.

Clark County Sheriff Joe Lombardo had previously said the guard was shot after gunman Stephen Paddock fired at the country music festival and that the guard's arrival in the hallway of the Mandalay Bay hotel may have caused Paddock to stop firing.

Mandalay Bay hotel-casino security guard Jesus Campos told investigators that he had been responding to a report of an open door when he heard drilling in Paddock's room.

Lombardo said late Monday that Paddock shot at Campos and then, minutes later, shot at the crowd below.

It was not immediately clear why the timeline of the shooting changed a week later or what the impact could be on the investigation.