we're learning it was an alarm from a room down the hall from the shoot early that brought a security guard up to the 32nd floor. police say they don't foe what plans the gunman might have had for several pounds of explosives and am nation found in his car. investigators are also saying the shooter brought his guns and am nation up to the room over the course of several days. i want to bring in cnn's scott mclean who is following the investigation from vegas. are police saying anything more about the possibility of the gunman may have had some sort of help? >> reporter: well, they say it's hard to imagine him not having any help. what they are confident of is the fact there was no one in the room with him at the time of the shooting or before the shooting. the what they cannot say for sure is whether or not he had any help or at the very least whether there's someone out there who had advance knowledge of this attack that was coming. they say they have combed