At least 20 rifles were found in the hotel room of Las Vegas gunman Stephen Paddock, a law enforcement official told The New York Times on Monday, along with hundreds of rounds of ammunition.
Among the guns found were AR-15-style assault rifles, another law enforcement official said.
Paddock used a hammer to smash out the windows, both law enforcement officials said. It was not clear whether the weapon was a sledgehammer.
At least 58 people were murdered and hundreds were wounded when the gunman opened fire at a country music concert at the Mandalay Bay resort just before 10:30 p.m. local time on Sunday night. The attack was the deadliest mass shooting in U.S. history.
64-year-old Paddock was found dead in his room at the hotel following the shooting.
The Islamic State (ISIS) terrorist organization claimed that Paddock was a convert to Islam and one of their fighters. However, the FBI later debunked the terror group's claims.