Oct. 12 (UPI) -- Authorities said it appears Las Vegas mass shooter Stephen Paddock was planning for a lengthy standoff with police after attacking a country music festival nearly three weeks ago.
Investigators are still collecting evidence from Paddock's hotel suite on the 32nd-floor of the Mandalay Bay Resort and Casino. According to detectives, the shooter made preparations that appeared to be efforts at holding off approaching police forces, ABC News reported Thursday.
Officials said Paddock had jammed the doors to his suite, making it difficult for anyone to get into the room -- and also had seized access to a service elevator, as a hotel perk for regularly playing at the casino. A gas mask was also found in his room.
Investigators have said Paddock placed hidden cameras inside and outside the room -- two cameras on a room service cart in the hallway, one on the peephole of the door and a baby monitor in the living room. Police said none of the devices recorded, though.
Aside from what was found in his room, Paddock also had stored 50 pounds of an explosive compound and 1,600 rounds of ammunition in his car.
Las Vegas authorities said they still haven't nailed down a motive for the attack, which became the deadliest mass shooting in U.S. history. Fifty-eight people died and more than 500 were injured. Wednesday, officials said they haven't found any evidence that Paddock, a regular gambler, had gaming debts.
The Las Vegas Review-Journal reported Thursday that a "do not disturb" sign on his door may have deterred housekeepers, allowing Paddock to set up his arsenal of weapons.
Some hotels may check up on a guest if they are believed to be ill, but there is no industry-wide standard on how long staff has to wait before checking in on hotel guests.
Although room service provided food at some time during his stay, it is possible that Paddock didn't allow anyone into the room in the days leading up to the attack.