The Las Vegas gunman set up a camera rig in the hallway outside his hotel room

Law-enforcement officials confirmed that the gunman in Sunday's mass shooting on the Las Vegas Strip had set up cameras in and outside of the hotel room, possibly to look "for anybody coming to take him into custody," Clark County Sheriff Joseph Lombardo told reporters on Tuesday afternoon.

At least one camera was set up on a food-service cart outside the hotel room to monitor incoming police, multiple news outlets reported.

"I anticipate he was looking for anybody coming to take him into custody," Lombardo said. "It was pre-planned, extensively, and I'm pretty sure that he evaluated everything that he did in his actions, which is troublesome."

The gunman, 64-year-old Stephen Paddock, had used a remote video camera that was connected to a tablet, in order to look for approaching police, sources told The Washington Post.

When law-enforcement officers managed to find Paddock in the hotel room on the 32nd floor of the Mandalay Bay Resort and Casino, he was already dead in what appeared to be a self-inflicted gunshot wound. Armed with dozens of guns and thousands of rounds of ammunition he purchased legally, Paddock killed at least 59 people who were among some 22,000 people attending a country music festival on the Las Vegas Strip. More than 500 people were injured.