Emergency Police Audio, 'Active Shooter, People Down'

The frantic police audio during the Vegas massacre underscores the terror at the venue as bullets rained down into the crowd.

You hear law enforcement in the audio frantically screaming as they determined the shots are coming from an upstairs room at the Mandalay Bay resort. Some scream about multiple people being hit.

And then there's this ... a warning to police to lock their police cars because people in the area are trying to take their rifles that are inside the vehicles.