Four casino employees have been arrested and charged with fraud and engaging in illegal gambling practices for their alleged involvement in a scheme that reportedly swindled a VIP gaming room in an unnamed Macau casino out of more than $3 million.

According to a report from GGRAsia, those charged include a casino pit manager along with a trio associated with an unidentified junket operator. The quartet allegedly stole cards from a VIP gaming room before secretly marking them in such a way as to give those involved in the fraud an unfair advantage during games of baccarat.

GGRAsia cited Ho Chan Nam, a spokesperson for the former Portuguese enclave’s Judiciary Police, as stating that the alleged fraud took place on Friday although it was unclear whether the cards in question had been passed through an electronic card shuffler prior to play.

“Every wager that the suspect made started with more than $128,950 staked,” Ho told GGRAsia. “Then in all the games played with a [single] shoe of cards, [the suspects] made winnings totaling $3.14 million.”

Ho explained that the alleged culprits were caught by the casino’s security team after only around 30 minutes of play while law enforcement officials were still examining how the cards could have been rigged and tracking other potential perpetrators not yet in custody.

“During the gambling, [the suspects] recorded the bets made in each game [and], with our initial investigation, they also allegedly [used] an illegal “multiplier”,” Ho told GGRAsia.

Ho declared that a “multiplier” is an illegal practice whereby VIP gamblers utilize a secret arrangement to magnify by several times any wagers made or monies won. As such, parties can avoid the near 40% tax levied by the Macau government on bets although the application can expose agents and players to potentially greater losses.

In May’s mid-term review of its casino market, Macau authorities proclaimed that they were considering the use of undercover agents to combat “multiplier” wagering while Ho stated that the $3.14 million gained by the alleged fraudsters did not include any monies that may have been won under such an arrangement.

GGRAsia reported that Macau’s VIP gambling market, which gathered momentum throughout 2015, has recently been rocked by a series of six-figure-plus thefts and frauds from junket rooms. Earlier this month, junket operator Dore Entertainment Company Limited confirmed that it had been a victim of alleged internal scam by a former employee at its VIP room inside the Wynn Macau Resort Casino although it did not publicize the precise amount of money involved. Moreover, January saw a gaming operations representative from the Casino Le Royal Arc complain to police that the venue had been the victim of a supposed swindle worth around $12.85 million.