Investigators said on Friday they're probing whether or not other people visited the Las Vegas shooter's room at the Mandalay Bay Resort and Casino, according to NBC News.
The investigators made two discoveries that have them questioning "whether someone else was in the Las Vegas gunman's hotel room when he was registered there," NBC reported.
For one, they found a phone charger that didn't match any of the phones in the room that Stephen Paddock rented.
And they discovereda key was used to get into his room at the same time Paddock's car had left the garage, NBC News reported.
"There are several possible explanations for these anomalies, the investigators say, but they want to get to the bottom of it," according to NBC News.
Investigators told CNN on Friday that Paddock took 20 cruises, several of which ported in Europe and the Middle East.
The cruise stopped in countries such as Spain, Italy, Greece, Jordan and the United Arab Emirates, CNN reported.
His live-in girlfriend, Marilou Danley, joined him on nine of the cruises, CNN reported.
Authorities continue to investigate Paddock's motive and the timeline of events before he killed 58 people and left nearly 500 injured in an mass shooting last weekend.
Paddock booked a hotel at The Blackstone Hotel in Chicago, and reviewed hotel options in Boston around Fenway Park.
Investigators hope that Danley, Paddock's girlfriend, can help piece together more about the shooter to understand why he committed the killings, The Washington Post reported.
"No one can put the puzzles together — no one except Marilou," said one women, who Seven Network Australia identified as her sister, according to The Washington Post. "Because Steve is not here to talk anymore. Only Marilou can maybe help."