and good evening from las vegas tonight. where authorities came before the cameras just a short time ago and revealed several stunning findings tonight. we now now the gunman was firing for nine minutes after that first 911 call came in. and what he had hidden in the hallway of the 32nd floor of that hotel right behind me. we are seeing inside the hotel. the door that s.w.a.t. teams broke down. it turns out he had a camera attached to a cart in the hallway so he would know when police were moving in. one of the 23 weapons he had with him in that room, the evidence marker still in place. and tonight, video of that very room taken by a tourist who stayed in that room just a year ago. and the view from the window, right down onto the concert site. the gunman checked into that hotel with ten suitcases. those suitcases were full of weapons. abc's senior national correspondent matt gutman on the suspect's final 48 hours.