LAS VEGAS — As Las Vegas began the process of recovering from one of the deadliest mass shootings in United States history, one question hung heaviest over the city on Tuesday: Why?
The authorities have yet to provide a motive for Stephen Paddock, 64, who killed at least 59 people and injured more than 520 others on Sunday when he unleashed a rapid-fire hail of bullets on an outdoor music festival.
Armed with at least 23 firearms, Mr. Paddock, who the police have described as a “lone gunman,” stationed himself in a 32nd-floor luxury suite of the Mandalay Bay Resort and Casino and fired into a crowd of thousands of people.
As investigators sketched a portrait of Mr. Paddock, a wealthy gambler and amateur golfer, survivors have described the scene of carnage in vivid detail: Thousands of concertgoers screaming and running for cover as the gunman’s victims fell around them.
• The police found Mr. Paddock dead in his room at the hotel. Investigators were still combing through his background.
• The federal authorities said there were no indications that Mr. Paddock had ties to any international terrorist organization, despite a claim of responsibility by the Islamic State.
• Marilou Danley, a woman described by the police as Mr. Paddock’s “companion” and a person of interest in the hours after the attack, has been cleared by the authorities. Ms. Danley, an Australian citizen, was not in the United States at the time of the attack.
• A registered nurse. A commercial fisherman. A school librarian. These are some of the victims.
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. Sheriff Joseph Lombardo of the Police Department said Mr. Paddock used multiple rifles during the attack.
A federal law enforcement official earlier said two rifles were 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.
The sheriff 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. He escaped from La Tuna federal prison in Texas in 1968 and 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 with CBS, 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.
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 event. 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. They thought they might be trampled as people fled the venue so they decided to join the rush to leave, she said.
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.
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.”
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.”
Patients surged into Sunrise Hospital and Medical Center, within walking distance of the concert, where at least 124 “met the criteria for trauma activation, said Dr. Jeff Murawsky, the hospital’s chief medical officer. They included patients with single and multiple gunshot wounds to the head, face, chest, body, arms and, in one case, a finger.
The response from Washington.
President Trump called the shooting “an act of pure evil” and said he would visit Las Vegas on Wednesday.
In a speech at the White House, Mr. Trump said the visit would come at “a very, very sad moment.”
Democrats hoped the tragedy would spur congressional action on gun control. “What Congress can do — what Congress must do — is pass laws that keep our citizens safe,” Senator Chuck Schumer, Democrat of New York, said on the Senate floor.
On Monday, Republicans gave no indication that they would pursue gun safety legislation.
Reporting was contributed by Ken Belson, Jennifer Medina and John Eligon from Las Vegas; Julie Turkewitz from Mesquite, Nev.; Vivian Yee, Jonah Engel Bromwich, Stephanie Saul, Matthew Haag, Rukmini Callimachi, Sheri Fink and Richard Pérez-Peña from New York; Gerry Mullany, Russell Goldman, Austin Ramzy, Alexandra Stevenson and Tiffany May from Hong Kong; Adam Goldman and Eric Schmitt from Washington; Liam Stack from London; and Lizette Alvarez from Miami.