Lombardo, who has been one of the key figures leading the investigation into Paddock's life and possible motives, revealed that the shooter left behind a note at the hotel room.
Ms Danley said she believed that it was Paddock's way of breaking up with her.
Sherriff Lombardo has said that investigators are remaining open to the possibility that Paddock may not have been working alone in executing the shooting-spree, with MSNBC reporting on Friday that a phone charger not matching Paddock's phone was found in the Mandalay Bay hotel suite.
The full "60 Minutes" interview with the four police officers will broadcast Sunday, Oct. 8 at 7 p.m. on CBS. The Route 91 Harvest country music festival, where the mass shooting took place, was located about 1,100 feet from the tanks.
She arrived late Tuesday at the Los Angeles International Airport from the Philippines. Paddock then booked a second room for an August 3 arrival. He also wired her money.
Authorities are looking into the possibility Paddock was planning additional attacks.
In a statement spoken by her lawyer, Ms Danley said her boyfriend was a "kind, caring and quiet man".
The shooter in the Las Vegas deadly massacre apparently planned to survive and escape in the moments after the massacre, but investigators did not specifically say how he meant to do that. There is no evidence that Paddock's act was an act of terror.
"It's hard to believe that one individual planned this attack and executed without anybody else knowing anything about it", McMahill said.
He said that it was only logical to "make the assumption" that Paddock had "some help at some point" in pulling off Sunday's massacre, pointing to Paddock's huge arsenal, explosive materials found in his vehicle and his meticulous planning.