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Stephen Craig Paddock, the 64-year-old white man who police say carried out the worst mass shooting in modern U.S. history Sunday night on the Las Vegas Strip moved frequently, buying and selling property in several states. But the twice-divorced retiree had one vein that seems to have run through the middle of his itinerant lifestyle — a love of casino gambling.

Police say that on Sunday night, Paddock broke out the window of a 32nd-story hotel room at the Mandalay Bay Resort and Casino and pulled the trigger, raining a hail of gunfire on concertgoers at the Route 91 Harvest country music festival across the street. Witnesses described what followed as "nonstop gunfire" that sent people fleeing for their lives.

At least 59 people were killed and more than 500 injured.

Las Vegas Sheriff Joseph Lombardo said Paddock checked into his room at the Mandalay on Thursday, but that police did not know what he had been doing in the days leading up to the shooting.

"He was a guy. He gambled," his younger brother, Eric Paddock, who lives in Orlando, Fla., told reporters Monday. "He was nice to my kids when they went out to Vegas."

Eric also seemed to rule out any ideological motive for his brother's actions. Asked if Stephen had been agitated about politics, he replied: "No religious affiliation. No political affiliation. He just hung out." He did say that his brother liked to play high-stakes video poker.

USA Today reports that authorities were looking into "recent transfers of large amounts of money involving the suspect and the possible relationship to gambling activities. An official who spoke to the newspaper said the review is part of a larger search into possible motives for the attack.

Although he had lived in California and briefly in Florida, in recent years, Stephen Paddock seemed to gravitate Nevada — specifically the gambling Meccas of Vegas and Reno. It was in Reno that he may have met Marilou Danley, the woman described by authorities as his companion.

Danley worked in Reno as a "high-limit hostess" in the Atlantis Casino Resort and Spa, the casino said in a statement. Although Atlantis did not confirm the dates of her employment — reportedly from 2010 to 2013 — it did say she had left the job "several years ago."

Records show that a few years after moving in with Paddock's condominium in Reno, Danley, an Australian citizen with family in the Philippines, divorced her husband of 25 years. Paddock sold the condo unit in Dec. 2016. Public records for Paddock show he was first married in 1977 and divorced in 1980. He married again in 1985 and was divorced from his second wife five years later.

He had addresses in Mesquite, Texas, Reno and Henderson, Nev., a suburb of Las Vegas. He settled last in Mesquite, Nv., about 90 minutes from the Vegas Strip.

Speaking to The Orlando Sentinel, Eric Paddock said his brother had also lived in Central Florida before moving to Nevada. He had some guns, but no automatic weapons, the brother said. "He's never even drawn his gun before," he said. He told CNN that his brother had owned "a couple of handguns."

But that picture was at odds with what police found in the shooter's hotel room and residence: "We have recovered 23 firearms at Mandalay Bay, and 19 firearms at his home in Mesquite [Nv.]," Las Vegas Assistant Sheriff Todd Fasulo said.

Two Nevada gun shops confirmed that the shooter had bought weapons from them, apparently in the past year. One of the shops, Guns and Guitars in Mesquite, issued a statement saying that "all necessary background checks and procedures were followed."

Lombardo said several pounds of ammonium nitrate, a chemical compound used in bomb-making, was found in Paddock's car.

The Palm Beach Post reported that a former neighbor of Paddock's in Florida said that when the two first met in 2013, Paddock told him he was a professional gambler as well as a real estate speculator. Paddock also reportedly told the neighbor that he traveled back and forth to Las Vegas.

Paddock had a private pilot's license. He had owned two different single-engine airplanes, selling the last more than a decade ago. He allowed his license to expire in 2010. He had a hunting and fishing license for Alaska.

Sheriff Lombardo said Monday that Paddock might have had a traffic citation — but had no criminal history in the state and that there were no immediate indications of such a history elsewhere.

Paddock's family also apparently has a dark past: Eric Paddock said his father held up multiple banks, broke out of prison and spent several years on the FBI's most wanted list. Speaking in an interview with CNN, he said sarcastically: "We're all proud. My father was on the Top 10 list for a while."

NPR has not independently confirmed that Benjamin Hoskins Paddock, the man from the Most Wanted poster, is the father of Stephen and Eric Paddock. A report in The Chicago Tribune from June 1969 states that a Benjamin Hoskins Paddock, then 42, was being added to the "10 most wanted men" list. It said the suspect had "once tried to run down an FBI agent with his car" and that Paddock, "known as 'Chrome Dome' in underworld circles because of his practice of shaving his head, has been diagnosed as a 'psychopath.' "

Eric Paddock said of his father: "I didn't know him; we didn't know him. He was in jail," adding that his father had "broken out of jail."

FBI Las Vegas Special Agent in Charge Aaron Rouse said at a news conference that the bureau has "determined, to this point, no connection with an international terrorist group." He was responding to reports that Paddock had recently converted to Islam and that the terrorist group Islamic State had claimed responsibility for the Las Vegas Strip attack.

A Las Vegas Metropolitan Police Department undersheriff called the attack an act of "domestic terrorism."

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