LAS VEGAS — A gunman on a high floor of a Las Vegas hotel rained a rapid-fire barrage on an outdoor concert festival on Sunday night, leaving at least 59 people dead, injuring 527 others, and sending thousands of terrified survivors fleeing for cover, in one of the deadliest mass shootings in American history.
Online video of the attack near the Mandalay Bay Resort and Casino showed the singer Jason Aldean’s performance at the Route 91 Harvest Festival, a three-day country music event, being interrupted by the sound of gunfire. The music stopped, and as victims fell bleeding, concertgoers screamed, ducked for cover, or ran. “Get down,” one shouted. “Stay down,” screamed another.
• The police found the gunman, whom they identified as Stephen Paddock, 64, dead in his room at the hotel. Investigators were still combing through Mr. Paddock’s background and searching his home on Monday.
• The Islamic State claimed that Mr. Paddock was one of its soldiers, but did not provide any evidence of its claim. The F.B.I. said there was no evidence so far that Mr. Paddock had ties to any international terrorist organization, and relatives said he had not displayed strong political or ideological beliefs in their interactions with him.
The police found an arsenal in the gunman’s hotel room.
At least 23 firearms, including a handgun, were found in Mr. Paddock’s hotel suite, according to the Las Vegas Metropolitan Police Department. Some were rifles equipped with scopes, said Sheriff Joseph Lombardo of the Police Department, adding that Mr. Paddock used multiple rifles during the attack.
A federal law enforcement official earlier said there were at least 20 rifles in the suite, along with hundreds of rounds of ammunition, including two rifles outfitted with scopes and set up on tripods in front of two big windows. Another official said that among the weapons were AR-15-style assault rifles. Both officials spoke on the condition of anonymity because they were not authorized to divulge details of the investigation.
Sheriff Lombardo said that Mr. Paddock brought at least 10 suitcases into his hotel room over a period of time.
Sheriff Lombardo said that Mr. Paddock fired through his hotel room door at security guards, striking one in the leg. The guard is still alive, he said. SWAT officers went in after the guard was shot.
In addition to the weapons at the hotel, the sheriff said the police retrieved 19 firearms, as well as explosives, several thousand rounds of ammunition and “electronic devices” from Mr. Paddock’s home in Mesquite, Nev.
Who was the gunman?
Mr. Paddock, 64, was described as a high-flying gambler who lived in a quiet retirement community and played golf. Officials said he had no significant criminal history and drew little attention to himself.
Investigators are trying to piece together his financial history to search for clues that could help determine what set him off.
Details about Mr. Paddock’s career and livelihood were sparse, aside from observations by neighbors and family members that he routinely gambled large amounts of money. “He was a wealthy guy, playing video poker, who went cruising all the time and lived in a hotel room,” a brother, Eric Paddock, said.
Mr. Paddock and his three brothers were raised by their mother, who told the children their father had died when in fact he was in prison, Eric Paddock said. Mr. Paddock’s father was convicted in 1961 of committing a series of bank robberies, and was sentenced to 20 years in prison, but escaped from La Tuna federal prison in Texas in 1968 and then became a used-car dealer and bingo parlor operator in Oregon.
The family moved around the country, from Iowa to Tucson to Southern California, another brother, Patrick Paddock II, said.
In an interview Eric Paddock said that his brother Stephen was “not an avid gun guy at all.”
“The fact that he had those kind of weapons is just — where the hell did he get automatic weapons?” he asked.
Guests at the Mandalay Bay are in shock.
The hotel was on partial lockdown Monday. While guests were allowed in the hotel through the parking structure in the back of the complex, the exits to the Strip were closed.
The casino floor was largely empty, though a few gamblers played slots. Several guests napped on couches, some covered in towels and bathrobes they had been given overnight.
A bellman at the hotel said the gunman’s car was still in the valet, which had been shut down.
Melissa Ayala, 41, came to the country music festival with four friends from Orange, Calif. They were drinking and laughing when they heard what they thought was fireworks. She did not realize it was gunfire until a man near them was grazed by a bullet and fell to the ground, blood coming from his neck.
“It seemed like rapid fire,” she said. “There was blood pouring everywhere.”
What about the ISIS claim?
The Islamic State claimed on Monday that the gunman was “a Soldier of the Islamic State,” but the group did not provide any evidence for its claim. The group has generally claimed violence carried out only by those directed by the terrorist group, or else by assailants who were inspired by their ideology. However, in recent months, the group has made at least two false claims, including for an attack on a casino in Manila and a bomb plot at Charles de Gaulle Airport in Paris.
Aaron Rouse, the F.B.I. special agent in charge in Las Vegas, said that so far there was no proof that Mr. Paddock had links to any international terrorist organization.
Citing a “source,” the terror group’s Amaq news agency said the assailant had “responded to calls for targeting Coalition countries.”
That phrase is a reference to a famous 2014 speech by Abu Muhammad al-Adnani, a former Islamic State spokesman, who called for sympathizers around the world to carry out violence in the group’s name on the soil of countries involved in the fight against ISIS.
In a second bulletin about the Las Vegas shooting, Amaq said the attacker had converted to Islam months earlier.
The gunman recently bought several weapons.
Christopher Sullivan, general manager of Guns & Guitars, a gun shop in Mesquite, Nev., confirmed that Mr. Paddock had bought three guns at his shop — a handgun and two rifles — within the last year. All the purchases were legal and cleared routine federal screening, Mr. Sullivan said.
“The man does not have a criminal history,” Mr. Sullivan said of Mr. Paddock.
Mr. Sullivan, who said he had also been contacted by the F.B.I. and the Bureau of Alcohol, Tobacco, Firearms and Explosives, would not provide detailed descriptions of the guns. “We have cooperated with local and federal authorities,” he said.
He described Mr. Paddock as seeming like “a normal fellow, a normal guy — nothing out of the ordinary.”
“As for what goes on in a person’s mind, I couldn’t tell you,” Mr. Sullivan said. “I know nothing about him personally.”
How did the shooting unfold?
The first reports of the shooting came at 10:08 p.m. local time. Officers were overheard on police radio channels reporting that they were pinned down by gunfire. Shortly before midnight, the Las Vegas police reported that “one suspect is down,” and soon after, the police said they did not believe there were any more active gunmen.
The Route 91 Harvest Festival bills itself as “three days of country music on the Vegas Strip,” and Sunday night’s performance was the last of the festival. The site of the concert, the Las Vegas Village and Festival Grounds, operated by MGM Resorts, sprawls over 15 acres and has a capacity of 40,000 people. The festival’s website said this year’s three-day concert was sold out.
Tenaja Floyd of Boise, Idaho, said many of the people around her in the concert crowd thought at first that the sounds came from fireworks, but “I knew immediately, that wasn’t fireworks.” She said her mother, Jennifer, threw her to the ground and lay on top of her to protect her. As people started running out of the venue, she said, they thought they might be trampled, so they decided to join the rush to leave.
Video of the shooting captured nine seconds of continuous rapid fire, followed by 37 seconds of silence from the weapon and panicked screaming from the crowd. Gunfire then erupted again in at least two more bursts, both shorter than the first.
The police reported clearing out the Mandalay Bay’s 29th floor and then working their way up to the 32nd floor. A police Twitter post described reports of an “active shooter” near or around the Mandalay Bay casino.
SWAT units swarmed the upper floors of the Mandalay Bay, closing in on the source of the shooting, a room on the 32nd floor where they found the gunman, the sheriff said. “We believe the individual killed himself prior to our entry.”
Video from the shooting showed Mr. Aldean, the final performer of the night, running off the stage as the gunfire erupted.
Jake Owen, a country singer who was on stage with Mr. Aldean when the shooting began, told CNN on Monday that it was like “shooting fish in a barrel from where he was.”
“This is not an exaggeration: This shooting was going on for at least 10 minutes,” he added. “It was nonstop.”
Concertgoers described hearing round after round of gunfire. “Everyone was running, you could see people getting shot,” Gail Davis, one of the witnesses, said. “I’ve never been that scared in my life,” she added. “To have this happen, I can’t wrap my mind around it.”