The slain gunman police described as the "sole aggressor" in the mass shooting at a Las Vegas concert was identified as Stephen Craig Paddock, 64, of nearby Mesquite.
Paddock opened fire from the 32nd floor of the Mandalay Bay Resort and Casino, killing at least 50 and wounding hundreds around 10:15 p.m. during a performance by Jason Aldean at the Route 91 Harvest Festival, authorities said.
A SWAT team blew open the entry to the 32nd-floor room of the hotel with an explosive and found Paddock dead, police said. The hotel was across the street from the outdoor venue.
Sheriff Joe Lombardo of the Las Vegas Metropolitan Police Department said "numerous firearms" were found in the room. A police source said a number were "long rifles". Paddock had been registered as a guest at the hotel since September 28.
Paddock had no history of criminality that would raise red flags, police said.
"All of the checks that we have been able to do other than a routine traffic violation here in Nevada and nationwide working with our local FBI partners have been able to find no derogatory history on that individual," Undersheriff Kevin McMahill said. "It's one of those really sad, tragic things that a man that's 64 years old that really had no other reason that we can find at least in his history here to go out and wound that many people."
Eric Paddock, the suspect's brother who lives in Orange County, Florida, told the Orlando Sentinel: "We are completely dumbfounded. We can't understand what happened."
The brother also told NBC News that Stephen Paddock was retired and was "just a guy" who frequented the hotels, gambled and attended shows. He had "no religious affiliation" and "no political affiliation, he added. "Not an avid gun guy at all," the brother told "CBS This Morning."
Stephen Paddock sold a house he owned in Melbourne, Florida, in 2015, the Sentinel noted, but it wasn't clear whether he lived there.
According to USA Today, Paddock bought his current residence in Mesquite, about 80 miles from Vegas, in 2015. The Sun City Mesquite senior complex features 1,400 homes, an 18-hole golf course, swimming pools and a recreation center.
Paddock owned two airplanes and had a private pilot's license, according to public records.
Meanwhile police had located his companion, Marilou Danley, "a person of interest," and do not believe she was involved, according to reports.
Authorities said they didn't know what had motivated the shooter.
Eyewitnesses said the gunman fired continuous bursts of automatic gunfire onto the crowd, then paused for 10 to 15 seconds and began shooting again.
Mesquite police assisted Vegas cops in securing the suspect's home and assisting in the search, a Mesquite PD spokesman told HuffPost.