When Mark Sampson, a resident of the sleepy retirement community of Mesquite, turned on the TV this morning, he saw a face that he recognized. It was the face of someone he had seen at the recreation center, where seniors in the Del Webb community play cards and watch TV.

“I said, ‘I recognize that guy,'” Sampson told The Nevada Independent this morning.

It was the face of Steven Paddock, 64, who unleashed a barrage of fire onto a concert crowd in Las Vegas last night, the deadliest mass shooting in American history. The rampage killed at least 58 people and injured more than 500 others, inundating Clark County hospitals who urged residents to donate blood. The shooting, which officials are not labeling terrorism, left many wondering what drove a 64-year-old retiree to open fire on a concert crowd.

It left Sampson and his wife wondering the same thing. Sampson had never met Paddock. But he said Monday morning that he had seen him around the planned community known as Sun City Mesquite, a retirement community that advertises itself as a place for “55+ active adults.”

“No one seems angry here. Everyone seems happy. Everyone waves,” said Carol Sampson, his wife. “Living in this kind of community, you don’t expect that. (It) is just unbelievable.”

Paddock settled in Sun City Mesquite, about an hour’s drive outside of Las Vegas, in 2015, according to multiple news reports. Officers executed a search warrant of his two-story home this morning. “It’s a nice, clean home and nothing out of the ordinary,” a Mesquite police department spokesperson told Reuters, though they found some ammunition and firearms.

He also owned a property in Northern Nevada. Paddock moved frequently, according to some news reports, and lived in Mesquite, TX near Dallas for eight years, according to the New York Times.

“He didn’t have active employment. His life is an open book,” his brother Eric Paddock, who helped move him to Mesquite, told the Times. “It’s all in the public record. He went to college, he had a job. You’ll find out.”

His brother was in disbelief and said Stephen Paddock had no military experience.

“When you find out about him, like I said, he’s a guy who lived in a house in Mesquite and drove down and gambled in Las Vegas,” he told the Times.

In recent weeks, Paddock reportedly made large gambling transactions, according to NBC News. He gambled more than $10,000 per day, according to the report, which was attributed to law enforcement officials and a casino executive. It did not indicate whether they were wins or losses.

Paddock shot at the concert crowd from the 32nd floor of a hotel room at the Mandalay Bay, where he was found dead when police arrived, said Las Vegas Sheriff Joseph Lombardo. In the room, there were at least 19 rifles, a law enforcement official confirmed to the New York Times.

Chris Sullivan, the owner of Guns & Guitars in Mesquite, confirmed in a statement reported on Twitter that his shop sold arms to Paddock. “Paddock was a customer and purchased firearms from our store; however, all necessary background checks and procedures were followed, as required by local, state and federal law,” Sullivan wrote. “He never gave any indication or reason to believe he was unstable or unfit at any time.” The store is cooperating with the investigation.

Sun City Mesquite, which is built around a golf course, is split into smaller neighborhoods with names like Prominence and Wishing Well. As of this afternoon, law enforcement officials were blocking entry to Paddock’s neighborhood. Crowds of reporters gathered around the area and neighbors drove by in golf carts to find out more information about Paddock’s motive.

One of his neighbors, Steve Bega, said he had returned from Las Vegas yesterday, hours before Paddock opened fire on the crowd. He said he was in disbelief. “It’s hard to believe anything like this could happen,” he said. Another neighbor, about to play a round of golf Monday afternoon, said he wouldn’t know Paddock “if he kicked me in the teeth.”

In 2011, Paddock sued the Cosmopolitan Las Vegas for negligence. He claimed that he slipped and fell on the “obstruction on the floor in an area intended for foot traffic,” sustaining “shock and injury to his body, nervous system and person,” according to the complaint.

Parties agreed to drop the case in 2014.

Jared Richards, who represented Paddock at the time, told The Nevada Independent that he was “horrified” by the news. “As indicated in public records, Stephen Paddock was a former client on an unrelated legal issue. As a matter of company and legal policy, we don’t talk about our clients before, during or after a case,” he said when reached on Monday.

Police have not released a motive.

“I can’t get into the mind of a psychopath at this point,” Lombardo said at a press conference.

The Smokin Gun Club sits in Arizona across the Nevada border, about five minutes away from Mesquite. Employees there spent several hours today checking for any potential paper records or surveillance footage of Paddock.

"At this point, we've been through all our records, and he has never been on our property," said Jason Shaw, a spokesman for the shooting range. "He has never come here to do any shooting, and we have had zero affiliation with him."

Shaw, who lives in Mesquite, said he was shocked by the news this morning and shocked that it involved several automatic weapons. "It's just the bad guys that have stuff like that," Shaw said.

He said no one out here owns automatic weapons.

"That's why he was such a surprise to people in this area," Shaw said, noting that most ranges in this area don't allow automatic weapons.

Like most residents, he wants to know the shooter's motive. "We've got a lot of questions," he said. "What's happened that made him do this?"

Around 5 p.m., police were letting traffic back into Paddock's neighborhood. His home, surrounded by police tape, was on a cul-de-sac at the end of the neighborhood.

Only two days ago, Kirk Hulburt, who lives at the neighborhood's entrance, had been driving his golf cart on the walking path that snaked behind Paddock's home. "Who knew that one day later he would be involved with this?"

Hulbert, who lives in Denver, uses his Mesquite place as a second home. At any given time during the year, he said it's not uncommon to find empty houses in the neighborhood.

"To think how many times he drove by and I waved to him," Hulbert said. "Every time he would leave or come home, he had to drive right by our house. Then to know he was bringing that much ammunition and firepower in."

Down the street, another group of neighbors were talking about Paddock, trying to wrap a new context around their past observations. "We never saw anyone outside there," Theresa Eastman said. "I questioned whether anyone lived there. The blinds were always drawn."

This story will be updated throughout the day.