A person who has seen Mandalay Bay hotel records says Stephen Paddock was comped his suite due to his gambling

Vegas gunman Stephen Paddock was staying at the Mandalay Bay hotel free-of-charge when he carried out America's deadliest mass shooting, it has been revealed.

A person who has seen hotel records that have been turned over to investigators said they show Paddock was gifted the luxury suite on the 32nd floor because he was a repeat customer who wagered tens of thousands of dollars each time he visited.

The individual was not authorized to speak publicly and disclosed the information to The Associated Press on condition of anonymity.

According to the Mandalay Bay's website, the Vista Suite that the shooter was staying in goes for $500 to $600 a night.

Comping rooms is common practice in Sin City, since it's an incentive for high-rollers to keep gambling.

Paddock was able to carry out the attack exploiting his insider knowledge of the popular Vegas hotel.

A hotel source told the Las Vegas Review Journal that the gunman transferred his arsenal to the suite in thirteen cases.

The gunman reportedly exploited the fact workers change every eight hours to move the weapons without detection.

He had checked into the room on Thursday September 28.

Paddock's brother has described the gunman as a high-stakes video poker player who was routinely comped rooms, meals and drinks at casinos.

'He was a substantial gambler. It was a job to him,' Eric Paddock said.

The massacre has brought new attention to the world of high-limit video poker and casino comps where high-rollers are given all sorts of free items to keep them gambling. The biggest gamblers - often known as whales - can get such perks as chartered planes, butlers and free lodging at a $35,000-a-night villa.

Paddock's brother said he was not at that level, but he gambled enough that he got free rooms, poolside cabanas and high-end sushi meals exceeding $1,000.

Vista Suites, like the one Paddock was staying in, typically go for $500 to $600 a night. Above, the hotel on Tuesday

Paddock's brother Eric said his brother was a 'substantial' gambler who regularly received free stuff from hotels

'He won cars and $250,000 checks and all this stuff from the hotel,' Eric Paddock said.

Video poker machines are a mainstay at casinos around Nevada, with most of the machines placed in bars where gamblers can play poker from their bar stools for 25 cents a hand. They look similar to slot machines.

Paddock favored the high-dollar variety version of the game, whose machines are separate from the main video poker and slot areas. Players like Paddock use strategies that can minimize the house winnings and in some cases gain a minuscule mathematical advantage.

Michael Shackleford, who runs a gambling strategy website called The Wizard of Odds, said based on what is known of Paddock's life, the gunman seems to have been what the casinos refer to as a 'premium mass' player - one who bets in higher amounts, with a better understanding of the game than the typical player.

Comping rooms is common practice in Sin City, since it's an incentive for high-rollers to keep gambling. Above a view of a typical Vista Suite

Paddock's brother has described the gunman as a high-stakes video poker player who was routinely comped rooms, meals and drinks at casinos.

Above, another view of a typical Vista Suite in the Mandalay Bay Resort and Casino

Vista Suites are 1,705-square-feet and have a king sized bedroom

Premium mass players pay close attention to the odds in the game they're playing and the payout, and they typically need access to a lot of money because they may have long dry spells where they lose exorbitant amounts.

Eventually, Shackleford said, if players stay true to a perfect strategy - one designed to maximize their performance over the long haul, such as by getting rid of potentially decent cards like low pairs to increase chances of a big-payout royal flush - their luck will turn, based on statistics, and they'll break even or come close to it. When you add in the freebies from the casino, the player can come out ahead.

'Vegas is full of people that are basically just gambling for free,' Shackleford said. 'I think the shooter was one of these people who was basically milking the system, getting free vacations.'

Why do the casinos have games where the players can come out ahead?

'It's because there are so many bad players,' Shackleford said. 'For every skilled player, there are probably 100 lousy players. They subsidize the skilled players.'

The stress of having so much on the line isn't for everyone, he said.

'In any form of gambling, you need a strong stomach and you need to have a very cool head about the ups and down,' he said. 'If this guy was a millionaire, it's quite possible he was not bothered by the ups and down. He probably had steel nerves and was a difficult person to move emotionally.'

Paddock used his room as a sniper's nest to attack a music festival on Sunday - killing 59 and injuring more than 400 before committing suicide. His body is seen on the floor of his suite, alongside two rifles

Above, more views of Paddock's suite after the attack on Sunday - now the deadliest in U.S. history

It's unknown how much he wagered, but he apparently had been wagering more than $10,000 a day in some cases.

A.G. Burnett, the head of Nevada's Gaming Control Board, said investigators are looking for enforcement actions, for any disputes Paddock may have had as a casino patron and at any federally required currency reports of transactions he made greater than $10,000.

Authorities have said Paddock used Danley's loyalty rewards card with MGM Resorts International. The tiered program allows players to accumulate credits and get perks such as bonuses on points earned playing slots, priority hotel check-in and - for those who belong to the highest and by-invitation-only level - limousine service to and from the airport.

'(The casinos) know whether he lost money because he never would have gambled for a second without putting the card in,' Eric Paddock said.