The Mohegan Sun Pocono casino in Pennsylvania has uncovered an internal theft ring that netted the scammers $419k of the casino’s money.

On Tuesday, Wilkes-Barre police arrested Robert Joseph Pellegrini, the casino’s VP of player development, on charges of theft, identity theft, fraud, conspiracy, computer trespassing and other transgressions. Also arrested was casino beverage server Rochelle Poszeluznyj and frequent casino customer Mark Joseph Heltzel.

Police said the scam involved Poszeluznyj collecting player reward ID and PIN numbers from customers when she took their drink orders. Poszeluznyj would pass on these numbers to Pellegrini, who would use them to make bogus reward cards, which were loaded up with free slot play credits.

The cards were then passed to Heltzel, who’d use them to gamble, while winnings were split among the three conspirators. The state police Bureau of Gaming claimed the scammers earned $418,793 in winnings from $478,100 in unauthorized free slot play between May 2014 and April 2015.