Police had said that after Paddock shot at Campos through the door, the gunman didn't fire any more shots into the crowd.
McKendry was parked in front of the Mandalay Bay hotel Sunday night when Paddock started shooting from his 32nd-floor room.
Campos told investigators that Paddock was drilling to an adjacent wall when he walked up to Paddock's room. Lombardo says a "comprehensive picture" is being drawn to show Paddock's mental state. Authorities didn't find a note in his room, only a paper with numbers, he said.
"Each time I push the button, it will range from $100 to $1,350", he said.
Paddock killed 58 and injured hundreds more.
"They weren't aware of him being shot until they met him in the hallway after exiting the elevator", Lombardo said.
Investigators expect to release a definitive timeline of Paddock's actions prior to the shooting once it is complete.
Investigators are still searching for the motive behind the attack by 64-year-old Paddock.
While Paddock aimed at fuel tanks across from the concert as a "diversion", Lombardo said it was clear that he meant to aim at the crowd enjoying a festival on the Vegas Strip.
"He actually cared about everybody", Lisa Crawford, who worked for Paddock managing an apartment he owned from 2006 to 2012, said.
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He said that the Federal Bureau of Investigation and Las Vegas Metro police had revisited Paddock's homes in Mesquite and Reno, looking for clues about a motive.
"Because this individual purposefully hid his actions leading up to this event, and it is hard for us to find answers for those actions".
Lombardo said that police have found "some evidence" Paddock was taking medication, however, he added that it has not led to a motive.
"We believe he made a decision to take the lives he did and he had a very purposeful plan that he carried out".
"We have uncovered over 200 instances of the suspects' traveling throughout Las Vegas and he has never been seen with anyone else", Lombardo said. Did Paddock intend to die in his hotel suite - shooting himself before a SWAT team breached the door on Sunday night - or had he hoped to escape?
Authorities have spoken to Paddock's brother and other family members, said Lombardo, who declined to discuss the interviews.
Lombardo declined to reveal what they've said, but he stated, "Every piece of information we get is one more piece of the puzzle".
According to Lombardo, Paddock had a document in the room with him, which contained numbers, but could not immediately say what they represented or what goal they served.
Authorities have begun to return personal effects of the concertgoers at the convention center in town.
People received their belongings in resealable plastic bags and were asked to check them.