The man who checked into a Las Vegas hotel and massacred dozens of concertgoers with a vicious deluge of bullets late Sunday lived in a quiet retirement community in Mesquite, Nev., about 80 miles northeast of Las Vegas, the police said. Relatives and neighbors said he and his companion drew little attention.
The gunman, identified by the police as Stephen Craig Paddock, 64, was described as a retiree who loved to gamble and who lived with his girlfriend, Marilou Danley, 62.
Relatives said Mr. Paddock had not displayed strong political or ideological beliefs in their interactions with him.
That modest portrait of Mr. Paddock was upended shortly after 10 p.m. Sunday when, according to the police, he opened fire on fans attending an outdoor country music concert near the Mandalay Bay Resort on the Las Vegas Strip, killing nearly 60 people and injuring at least 500 others.
Mr. Paddock was found dead from a self-inflicted gunshot in his room on the 32nd floor of the hotel, said Sheriff Joseph Lombardo of Clark County, which includes Las Vegas.
More than 19 rifles were found in the hotel room, a law enforcement official confirmed, along with hundreds of rounds of ammunition. Two rifles with scopes were mounted on tripods and positioned in front of the two windows in the hotel room.
Sheriff Lombardo described Mr. Paddock as “lone wolf” who had smashed the window of the hotel with a hammer-like device before starting to fire on the crowd.
A motive for the horrific attack remained unclear. “I can’t get into the mind of a psychopath at this point,” Sheriff Lombardo said.
“It wasn’t evident that he had weapons in his room,” the sheriff said. “It has been determined that he had employees going to and fro from his room, and nothing nefarious was noticed.”
His brother, Eric Paddock, who lives in Orlando, said he and his family were “shocked, horrified” by the news, saying he was “not an avid gun guy.” The brother told CBS News that he knew Mr. Paddock had handguns, but that as far as he knew, Mr. Paddock did not own “machine guns.”
“Where the hell did he get automatic weapons? He has no military background or anything like that,” the brother said. “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 said he last communicated with his brother when Stephen inquired about how the family had fared during Hurricane Irma, which struck Florida in September.
“He texted me to ask about my mom after the hurricane,” Eric Paddock told reporters. “He sent her a walker.”
Christopher Sullivan, general manager of Guns & Guitars, a gun store in Mesquite, confirmed that Mr. Paddock bought three guns at his shop within the last year — a handgun and two rifles. All the purchases were legal and cleared routine federal screening, Mr. Sullivan said.
“The man does not have a criminal history,” he said of Mr. Paddock.
Mr. Sullivan, who said he had been contacted by the F.B.I. and the Bureau of Alcohol, Tobacco, Firearms and Explosives, declined to provide detailed descriptions of the guns Mr. Paddock bought. “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,” who described himself as a “snowbird” because he spent half the year in northern Nevada.
“As for what goes on in a person’s mind, I couldn’t tell you,” Mr. Sullivan said. “I know nothing about him personally.”
The Islamic State militant group claimed on Monday that Mr. Paddock was one of its soldiers, but did not provide any evidence to support its claim. The F.B.I. said there was no evidence so far that Mr. Paddock had ties to any international terrorist organization.
But Eric Paddock told reporters in Florida that his brother “had nothing to do with any political organization, religious organization, no white supremacist, nothing, as far as I know. And I’ve only known him for 57 years.”
A spokesman for the Mesquite Police Department said there was nothing remarkable about Mr. Paddock’s home, in a cul-de-sac in a “fairly quiet” retirement community.
He described the area as “just a regular neighborhood” and added that nothing was “out of the ordinary” when police searched the home on Monday. The spokesman said some weapons and ammunition were found in the house but would not specify the type or quantity.
The Mesquite Police Department said they had no interactions with the couple, including traffic stops. Eric Paddock said that Ms. Danley was his brother’s girlfriend and that he did not think that they were married.
Ms. Danley worked as hostess at the Atlantis Casino in Reno, Nev. from 2010 to 2013, according to her LinkedIn Account. On Monday, the casino confirmed Ms. Danley’s employment and said that she left the company several years ago.
Her LinkedIn account said that she worked as a “high limit hostess,” attending to members of a loyalty club called Club Paradise who spent large quantities of money and received discounted hotel rooms, meals and other amenities, according to the casino’s website.
Other details about Mr. Paddock’s life and hobbies have begun to emerge in the hours since the attack.
Mr. Paddock had a private pilot’s license, according to Federal Aviation Administration, and had two small single-engine planes registered in his name. There are no records of Mr. Paddock having served in the military.
Mr. Paddock’s ex-wife, who now lives near Los Angeles, told the Los Angeles police that they had divorced 27 years ago after being married six years. They had no children.
His brother described Mr. Paddock as a wealthy guy who liked to play video poker and take cruises.
“He didn’t have active employment. His life is an open book,” the brother said. “It’s all in the public record. He went to college, he had a job. You’ll find out.”
Mr. Paddock spent several years living in Mesquite, Tex., an eastern suburb of Dallas. From 2004 and 2012, Mr. Paddock was associated with several properties in the city and had a Texas driver’s license that has now expired, according to a spokesman for the Mesquite police department.
“We have no record that we have dealt with him in any way,” said the police spokesman, Lt. Brian Parrish. “We have no record that we’ve ever dealt with him.”
Speaking to FloridaToday in Viera, where Mr. Paddock had a home, a neighbor, Sharon Judy, described Mr. Paddock as “a normal man.”
“He seemed normal, other than that he lived by gambling,” Ms. Judy told FloridaToday. “ He was very open about that. First time we ever met him, he handed us the key to the house and said, ‘Hey, would keep an eye on the house, we’re only going to be here every now and then.’ ”
Details of Mr. Paddock’s employment history are sparse.
Lockheed Martin, the aerospace contracting company created by a 1994 merger, confirmed that he worked for one of its predecessor companies from 1985 to 1988. Lockheed Martin did not identify which company Mr. Paddock worked for specifically. The company said it was cooperating with law enforcement.
According to business documents, Mr. Paddock once owned a working-class apartment complex in the Dallas suburb of Mesquite, Tex. A resident, Priscilla McBride, told The Dallas Morning News that Mr. Paddock often roamed the apartment property, casually talking to residents.
He moved away several years ago, she said, and they had not seen each other since. “I thought, it couldn’t be,” she said. “You would have never thought he would be killing people. You just never know.”
The road leading to Mr. Paddock’s Mesquite, Nev., house was blocked on Monday, after the neighborhood was thrown into chaos by the news.
“It’s quiet and peaceful here,” said Rose Dean, a resident of the community, which accepts residents 55 and older. “Everybody takes walks and waves at each other.”
Ms. Dean, who has lived in the retirement community for eight months, said she did not remember meeting Mr. Paddock and was shocked to learn that he lived in Mesquite.
“Someone called me this morning and said, ‘Hey, that was your neighbor!’ ”
Mr. Paddock’s father, Benjamin Patrick Paddock, had a troubled history. He 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 1968, and was on the F.B.I.’s “Top Ten” most wanted list, through most of the 1970s, according to someone familiar with the investigation.
News accounts from the time said that Benjamin Paddock “employed violence in attempting to evade arrest, and has been diagnosed as being psychopathic, with possible suicidal tendencies.” He was recaptured in 1978 in Oregon, where he was running a bingo parlor.
Benjamin Paddock was also convicted in Illinois in 1946 on 10 counts of auto theft and five counts of running a confidence game. Eric Paddock said the brothers did not know their father.