Dina Titus Nevada lawmakers told CNN that Stephen Paddock had several weapons and hammers in his room, but the entire arsenal of dozens of guns was "very well hidden".
US officials believe Paddock brought the weapon into the hotel himself, but did not disclose details.
On October 1, when the Route 91 Harvest concert was taking place outdoors several hundred meters from Paddock's hotel room, he broke a window in the front and one in the corner of the room, then carried out the bloodiest shooting in American history, killing at least 59 people and injuring more than 520 others.
Las Vegas police said they discovered 23 guns in a hotel room and 19 guns in Paddock's private home in Mesquite, Nevada.
The room that Paddock rents is a large suite-class room with a panoramic view of the famous Las Vegas Strip. Paddock was able to observe the parking lot very carefully when the concert was held, on the other side of the road, about 360m away.
In the previous few days, Paddock had brought more than 10 suitcases into his room.
CNN analyst Art Roddick said he was shocked by Paddock's careful plan.
"Shooting from a high position is something that shooters always want to do, so I wouldn't be surprised if we had a few videos showing paddock standing at the concert venue, looking up at the Mandalay Bay Hotel and trying to find the most suitable room," said Roddick.
"You could see two broken windows, one in the front and one in the corner, giving him two different shooting angles, and that was all the plan of the perpetrator."
This expert commented that because there were many people in the hotel, the police could not fire back from the ground.
"It was a big hotel, and that's why it took the police an hour and 12 minutes to pinpoint paddock's room," Roddick said.
