LAS VEGAS — Stephen Paddock was known to sit for hours playing slot machines and video poker, gambling with tens of thousands of dollars and earning VIP status and the lavish “comps” that casinos shower on their regular high-rollers to keep them playing.

Paddock used the perks liberally, indulging in limousine rides, spending complimentary cash on Swarovski crystal jewelry in casino gift shops, and staying in free hotel rooms and suites. His family members have said he considered casinos as a second home and gambling a retirement profession.

Much is still unclear about Paddock’s gambling history, but it is clear that casinos in various cities were a big part of his life. They also were a central aspect of his final act: He carried out the deadliest shooting rampage in modern U.S. history from a luxury suite on the Mandalay Bay Resort and Casino’s 32nd floor, from which he shot and killed dozens of people and wounded more than 500 on Sunday.

Those who knew Paddock are perplexed by the extreme violence, but not by his presence in a Las Vegas casino that night. Dealers, waitresses, security guards, bartenders, drivers and family members said Paddock was a committed gambler who spent much of his time in casinos, playing their slots and video poker games and living in their hotels sometimes for months at a time.

A person familiar with Paddock’s gambling history, who spoke on the condition of anonymity, said Paddock was considered a midrange gambler whose wins and losses were in the tens of thousands of dollars – placing him in the middle tier of VIP programs for loyal gamblers.

“This is a man who clearly enjoyed gambling. He is someone who won and lost money through the years. He paid all of his bills and did so on time . . . never having any sort of incident,” the person said. “He has the profile of a responsible gambler.”

Paddock frequented casinos in Reno, Nevada, where he recently bought a home in a new retirement subdivision. He met his girlfriend, Marilou Danley, several years ago while she was working as a high-limit hostess for Club Paradise at the Atlantis Casino Resort Spa, known as the highest-end casino in Reno, said Paddock’s brother, Eric Paddock. The two used to gamble side by side.

Casino employees in Reno were used to seeing Paddock and Danley roll up to the Atlantis in a limo before a night of play. She was friendlier; he was more taciturn. Sometimes they came together, sometimes alone, said employees who worked at casinos across Reno, speaking on the condition of anonymity because casino managers had ordered them not to discuss Paddock publicly.

A woman who worked with Danley at the Atlantis in Reno said Paddock had achieved the casino’s highest loyalty-program status, which affords gamblers a host of privileges, including a personal casino host, premium seating at concerts and events, and complimentary carwashes – he also ordered meals off the restaurant menus and had them delivered to him as he gambled.

Eric Paddock said his brother essentially moved into the casino for months at a time.

Paddock also frequented other Reno casinos. He earned a reputation as a big spender at the Grand Sierra, and he was spotted in recent weeks at the Silver Legacy, where a dealer said he was known to wager $100 per bet on slot machines.

A casino employee said Paddock was a frequent presence during the National Championship Air Races in September. Public records show that Paddock owned two planes and was a licensed pilot.

“It’s like a job for him. It’s a job where you make money,” said Eric Paddock

Relatives said they believe Paddock was worth more than $2 million, making a small fortune from real estate deals and a business that he and Eric sold.