A wealthy retired accountant opened fire from a hotel room above a packed outdoor concert in Las Vegas, killing at least 59, wounding 527 more and triggering a stampede as the panicked crowd scrambled for cover amid the deadliest mass shooting in modern U.S. history.

Gunman Stephen Craig Paddock, 64, an avid gambler who enjoyed playing high-stakes poker, killed himself shortly before officers stormed his 32nd-floor room at the Mandalay Bay Resort and Casino, said Clark County Sheriff Joe Lombardo.

As of late Monday, authorities seized over 40 firearms that Paddock had either in his hotel room or at his home in Mesquite, Nev., where police also seized explosives and thousands of rounds of ammunition. Another search warrant was executed Monday at a separate home that Paddock owned in Reno, but details weren't released as to what was found in that house.

Lombardo described Paddock, the son of a 1960s bank robber who was on the FBI's most-wanted list after escaping from prison, as "a distraught person intent on causing mass casualties." Lombardo said Paddock was likely a "lone wolf" and that a motive for the shooting had not been determined.

"This is a crazed lunatic full of hate," Las Vegas Mayor Carolyn Goodman said. "This has been a hugely traumatic time for all of us."

Paddock had checked into the Mandalay Bay on Sept. 28, but officials couldn’t say by Monday evening whether he specifically requested the towering room. They also couldn’t offer a definite timeline of Paddock’s actions in the days leading up to the shooting, the moments during the massacre, or how Paddock managed to transport nearly two dozen weapons into his room undetected.

Assistant Sheriff Todd Fasulo said he knew the public was eager to understand Paddock’s motive, but urged patience during the investigation.

“We’re hunting down and tracing down every clue we can get in his background,” he said.

Other officials touted the city’s resilience in the aftermath of the city’s tragedy. Blood banks were now stocked, and by Monday evening were turning away would-be donors. And a GoFundMe page had collected more than $2.2 million from 30,000 donors, including a $400,000 donation from Stephen Cloobeck, the founder of Diamond Resorts International.

Paddock’s brother, Eric Paddock, who lives in Florida, says his multimillionaire brother was a big spender at casinos and often received free meals and rooms there.

With hospitals jammed with victims, authorities put out a call for blood donations and set up a hotline to report missing people and speed the identification of the dead and wounded. They also opened a “family reunification center” for people to find loved ones.

More than 12 hours after the massacre, bodies covered in white sheets were still being removed from the festival grounds.

President Trump addressed the nation Monday from the White House, calling the attack "an act of pure evil" and ordering flags flown at half staff. He thanked first-responders for their "miraculous" efforts and said he would visit Las Vegas on Wednesday.

The mass shooting underscored how easy it can be to bring weapons and other contraband into hotels . Although it wasn't immediately clear how Paddock got the weapons and ammo to his room, security experts say he easily could have hid them in innocuous containers.

"You can bring a long gun in disassembled in a small suitcase. Nobody would think twice about somebody carrying in a golf bag, or something like a big snow ski bag," said Angela Hrdlicka, a former Secret Service agent who is now a private security consultant for Major League Baseball parks and other professional sports.

Lombardo said officials have yet to locate any manifesto or other indication of motive.

Lombardo laid out the frantic minutes between the shooting and officials locating Paddock in his 32nd-floor hotel room. He said officers received information from security that the shooter was likely staying between the 28th and the 32nd floor.

A team of six officers approached security, went up in elevators and checked “each floor, floor by floor,” until they reached Paddock’s room, he said.

As they approached the room, the team came under fire and one security guard was shot in the leg. The team then backed off for a SWAT team to intervene. They were able to gain entry into the room and found Paddock dead.

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The three-day Route 91 Harvest festival started Friday, and Lombardo estimated that 22,000 people were in the crowd when the shooting began Sunday at about 10 p.m. local time.

The festival's headliner, country music singer Jason Aldean, was on stage when the barrage of bullets began and continued to play through the first, extended volley, video from the scene shows. The crowd appeared confused, unsure what the sound was.

The music stopped at about the same time the volley did, but after several seconds another, lengthy round of gunfire began, setting off bedlam in the crowd. Videos on social media show people ducking for cover and fleeing amid the unrelenting bombardment.

Cassie Manzanares, who was covering the festival for a Utah radio station, said she heard a "popping" noise.

"I've shot guns before, and it didn't sound like a gun," Manzanares said. "I thought maybe someone was doing firecrackers as a joke, or something happened with the pyrotechnics. But the next round (of gunfire) started, and that's when we heard the screaming."

Terrified, she said she froze. But a friend was shot, and she said she realized they had to run.

"We jumped over the wall and there were just bodies and blood and people screaming and trying to get away," Manzanares said. "People were breaking down fences to use to carry the bodies."

Justin Zimmerman, of Dexter, Iowa, said he was with four friends when the carnage began.

"I left my friends to go get more beer, then you heard a distinct 'Pop! Pop! Pop! Pop!,'" he said. "(I) thought it was the sound guy messing up, but you learn quickly it's actual gunfire."

He said he, too, froze and then hit the ground. Eventually he ran to the safety of a nearby casino.

Among the victims was Sonny Melton, 29, a registered nurse from Big Sandy, Tenn. "He saved my life," his wife, Heather, said. "He grabbed me from behind and started running when I felt him get shot in the back."

Aldean confirmed that he and the rest of his team were safe.

"Tonight has been beyond horrific," Aldean posted on Instagram. "It hurts my heart that this would happen to anyone who was just coming out to enjoy what should have been a fun night."

Aaron Rouse, chief of the FBI’s Las Vegas office, disputed an Islamic State claim that Paddock was one of the militant group's soldiers. Rouse said no connection to the militant group had been found.

"We have no idea what his belief system was," Lombardo said. "We believe he was the sole aggressor."

Authorities were reviewing the recent transfers of large amounts of money involving the suspect and the possible relationship to gambling activities, a federal law enforcement official said. The official, who was not authorized to comment publicly, said the review is part of wide-ranging search for a possible motive in the attack.

Lombardo said Paddock checked into the hotel Thursday. He said that when the shooting started, authorities could see the gunfire was coming from Mandalay Bay. Employees and guests helped direct officers to the room. Officers used explosives to "breach" the door and found Paddock's body.

About 23 weapons, many of them rifles, were found inside Paddock’s hotel room, authorities said at a late press conference Monday.

A federal law enforcement official, who has been briefed on the matter but is not authorized to comment publicly, said that police also found two tripods positioned at the hotel windows in what appeared to be a fully-equipped sniper’s nest to take better aim at the crowd below.

Hundreds of rounds of ammunition were among the suspect’s possessions, a cache that could have sustained him in a much longer assault, the official said.

The Associated Press also reported that two of the weapons were modified to make them fully automatic, according to two U.S. officials briefed by law enforcement who spoke on condition of anonymity because the investigation is still unfolding.

Authorities believe that the gunman, who had no serious criminal background, purchased many of the weapons legally. Though investigators were attempting determine whether he illegally converted some to operate as fully automatic weapons, the official said.

Lombardo said authorities also searched Paddock's home and found even more weapons — 19 firearms, explosives, and unidentified electronic devices, as well as thousands of rounds of ammunition.

Guns & Guitars, a shop in Mesquite, confirmed that Paddock had purchased guns from them in a past. Manager Chris Sullivan said all necessary background checks and procedures were followed.

"He never gave any indication or reason to believe he was unstable or unfit at any time," Sullivan said. "We are currently cooperating with the ongoing investigation."

Mesquite is a town of about 18,000 people 80 miles northeast of Las Vegas. Paddock lived in a retirement community, Sun City Mesquite, an upscale development of about 1,400 homes. The community includes an 18-hole golf course, indoor and outdoor swimming pools and a recreation center. Residents must be at least 55 years old, and no children are allowed.

Paddock's brother, who lives in East Orlando, Fla., said that to his knowledge, his brother had no history of mental illness or substance abuse. He said his brother had "nothing to do" with political or religious organizations. His brother owned guns and played high-stakes video poker, he said.



"There's absolutely no way I can even conceive that my brother would shoot a bunch of people he didn't even know," Eric Paddock said. "There's no rationale. There's nothing anywhere that said why he did this."

The FBI confirmed that the shooter’s father was a bank robber who reached the FBI’s Top Ten Most Wanted list in 1968 after escaping prison. The wanted poster described Benjamin Paddock as a "psychopath" and "very dangerous." He was recaptured 10 years later and has since died.

Lombardo said police had named Paddock's roommate, Marilou Danley, as a person of interest. She is out of the country, and Lombardo said she will be questioned further upon her return.

City officials urged local residents to donate blood as blood drives organized across the city drew long lines. Kay Anne Johnson, 32, who has lived in Las Vegas for about six years, said she fell asleep before she knew the extent of the shooting spree. Her husband woke her at 5 a.m. with the tragic news.

"At that point, you aren't going back to sleep, she said. "You get up and try to find a way to help."

Pope Francis expressed his “spiritual closeness” to victims and promised his prayers in a telegram addressed to the Bishop Joseph Anthony Pepe of Las Vegas.

Nevada Gov. Brian Sandoval called the shooting a "cowardly" act.

"We are angry, we are grieving," he said. "We're confused. People are hurting."

Contributing: Jane Onyanga-Omara, Alan Gomez and Kevin Johnson, USA TODAY; Emily Havens, The Spectrum and Daily News; Caroline Glenn, Florida Today; Aaron Young, The Des Moines Register; Brett Kelman, The Desert Sun; Josh Susong and Megan Cassidy, The Arizona Republic; Associated Press