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.
• Speaking at the White House, President Trump condemned the shooting as an “act of pure evil” and called for the country to come together, saying, “Our unity cannot be shattered by evil, our bonds cannot be broken by violence.”
The police found an arsenal in the gunman’s hotel room.
At least 17 firearms, including a handgun, were found in Mr. Paddock’s hotel room, said Sheriff Joseph Lombardo of the Las Vegas Metropolitan Police Department. Some were rifles equipped with scopes, he said, 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.
The police also found ammonium nitrate, a fertilizer that can be used in explosives, in Mr. Paddock’s car in Las Vegas.
In addition to the weapons at the hotel, the sheriff said the police retrieved “in excess of” 18 firearms, as well as explosives, several thousand rounds of ammunition and “electronic devices” from Mr. Paddock’s home in Mesquite, Nev. He said the police were evaluating the electronic devices, which he did not describe.
Who was the gunman?
Mr. Paddock, 64, of Mesquite, had no significant prior criminal history, officials said. Investigators are trying to piece together Mr. Paddock’s financial history to search for clues that could help determine what set him off. The F.B.I. has sent dozens of agents and evidence technicians to Las Vegas.
The gunman’s father, Benjamin Patrick Paddock, had a troubled history, according to Eric Paddock of Orlando, Fla., a brother of the suspect. Benjamin Paddock was convicted of serial bank robbery in 1961, according to news reports from the time. After he escaped from prison, he was on the F.B.I.’s “Top 10” most wanted list for much of the 1970s.
Eric Paddock said he had made a statement to the police. In an interview with CBS, he said that his brother was “not an avid gun guy at all,” adding, “if he had have killed my kids, I couldn’t be more dumbfounded.”
“The fact that he had those kind of weapons is just — where the hell did he get automatic weapons?” Eric Paddock asked.
“He has no military background or anything like that,” he added. “He’s a guy who lived in a house in Mesquite and drove down and gambled in Las Vegas.”
He said Stephen Paddock had recently texted him to ask how their mother was faring after Hurricane Irma.
Sheriff Lombardo said that Marilou Danley, whom he called Mr. Paddock’s girlfriend, was in Tokyo, and the police were arranging to interview her when she returns to the United States.
Before dawn on Monday, the police searched Mr. Paddock’s house in Mesquite, a town on the Nevada-Arizona border. The police moved cautiously at first, evacuating surrounding homes in case there were any explosives, but none were found. The Mesquite Police Department said no one was in the house; at least one firearm and ammunition were found, they said, but they gave few other details about what the search turned up.
The police blocked off the entrance to the neighborhood, but Tom Jennings, 76, a forensic engineer, emerged to check his mail. “This is not Mesquite,” he said, wide-eyed and clearly shaken.
“It makes you sick,” he said. “You just never know who you are living next door to.”
Guests at the Mandalay Bay are in shock.
The hotel remained on partial lockdown late Monday morning, as it had since the shooting. The casino floor was largely empty, though a few gamblers played slots. Hotel employees were offering coffee, pastries and cases of water to stranded guests.
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.”
“Where do you run to?” said her friend, Shami Espinoza, 38, as she wiped away tears.
“It’s either run and get shot and die or stay and get shot and die. Those were the choices.”
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. It has previously made false claims about its role in some terrorist attacks.
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., said he was awakened at 4 a.m. Monday by a telephone call from the Las Vegas Metropolitan Police Department, which was tracing Mr. Paddock’s guns.
Mr. Sullivan 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.
In the confusion after the shooting, the police also descended on the Ali Baba Restaurant, about a 10-minute drive from the Mandalay Bay, and investigated reports of a shooting at the New York-New York Hotel and Casino, not far from the concert ground.
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 with “in excess of 10 rifles,” 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.”
The president calls the shooting ‘an act of pure evil.’
Speaking at the White House, President Trump called the shooting “an act of pure evil,” ordered flags flown at half-staff, and said he would travel to Las Vegas on Wednesday.
“The F.B.I. and the Department of Homeland Security are working closely with local authorities to assist in the investigation,” Mr. Trump said, and he praised the performance of the Las Vegas police. “The speed with which they reacted was miraculous and prevented further loss of life.”