Las Vegas gunman Paddock checked in to his hotel 4 days before the shooting

Flickr/ Erin Khoo

Stephen Craig Paddock, the gunman behind the worst mass shooting in modern US history, had checked into his Las Vegas hotel room on September 28, four days before opening fire on a crowd of 22,000 from his hotel window.

Paddock shot an automatic rifle out the window of his hotel room on the 32nd floor of the Mandalay Bay Resort and Casino during the final act of the Route 91 Harvest Festival, which took place in a lot adjacent to the hotel.

Extended bursts of rapid fire can be heard on videos of the massacre. When police entered Paddock's room they found him dead with more than 10 rifles. 

It's unclear if Paddock had the rifles with him throughout his stay. Paddock owns a home in Mesquite, Nevada, about an hour and a half away from the scene of the shooting by car. 

Paddock's brother Eric told the Daily Mail that his family was "shocked" and "dumbfounded" by Paddock's actions and that there were no indications as to a possible motive before the shooting.

Joseph Lombardo, the sheriff of the Las Vegas Metropolitan Police Department, told reporters that Paddock checked into the hotel using some identification from Marilou Danley, his roommate in Mesquite.

Police have located Danley out of the country, and are not pursuing her at this time. Google Earth/Business Insider