http://beta.latimes.com/nation/la-na-las-vegas-guard-20171010-story.html
New disclosure shows a casino guard alerted hotel to gunman before Las Vegas massacre began. So why did it take so long to stop him?
The revelation that hotel security had been alerted comes a day after Las Vegas police changed their timeline of how the Route 91 Harvest country music festival massacre started on Oct. 1 — not with an attack on a crowd along the Strip at 10:05 p.m., but with the shooting of Mandalay Bay security guard Jesus Campos inside the hotel about six minutes before.
"He called it in before" the attack began, possibly using a hallway phone to contact hotel security, Clark County Assistant Sheriff Tom Roberts told The Times in an interview. "He manually called down and he used his radio to call. … That's what we were briefed this morning."