Management at B.C.'s River Rock Casino have suggested that employees use their discretion when they see high rollers breaking rules meant to prevent money laundering, according to an internal email obtained exclusively by CTV News.

Casino chips can be valuable tools for criminals to launder money, and they're a lot more discreet than wads of cash. That's why there's a provincial rule against passing chips between players; normally, employees are supposed to talk to gamblers they see breaking the rules.

But in the fall, staff at the River Rock in Richmond sent an email to staff saying: "There are two players that could be big ... After speaking to some Head Office people it is perfectly acceptable not to approach guests on a chip pass if you feel it is not suspicious."

The casino would not comment on the email.

There was a spike in the number of large suspicious transactions at the River Rock in January, and another email obtained by CTV News describes one incident.

It involved one of the casino's biggest customers, "Mr. S," and his associate "Mr. Chen." Surveillance cameras spotted them in the River Rock parkade with their cars parked side by side.

Mr. S eventually gets into his car and pulls out a red bag. He then apparently puts cash into the bag and the two men go into the high-limit betting area, where they both enter the washroom.

Then Mr. S comes out and buys in for $100,000 -- all in $100 bills.

This wasn't the first time Chen was cited for suspicious transactions. At the Starlight Casino in New Westminster, he had racked up eight suspicious transactions dating back to September.

After the incident in January, the BCLC barred Chen from all casinos in the province for a year. Mr. S is still welcome.

The BCLC would not specify how many suspicious transactions are necessary before a gambler will be barred from casinos.

After CTV showed both of the emails to B.C. Lottery Corporation officials, they confirmed that investigators flagged both incidents as suspicious transactions and sent reports to Fintrac, the RCMP's proceeds of crime unit and the Gaming Policy Enforcement Branch.

BCLC President Michael Graydon says there's a strict policy against passing chips.

"Technically, you're not supposed to pass chips, and if we find you passing chips, then we will fill out a suspicious transaction form and ask you to leave the facility," he said.

He insists that officials are working to crack down on suspicious transactions.

"We all collectively are working very hard at it. We have many, many layers of risk mitigation in place, many layers of security and enhanced training for all of the staff. We continue to work at it, because it's not part of the reputation that we want in our industry," he said.

CTV News has also learned that some casinos will be issuing warning cards the first time gamblers are caught passing cash or chips.

But critics aren't convinced. Opponents of a $450-million casino complex planned for downtown Vancouver believe it will bring organized crime into the city centre.

"The lifeblood of organized crime is being able to launder money and we have to start taking this issue extremely seriously," said Sandy Garossino of the "Vancouver not Vegas" coalition.

"What are the controls? Who's in charge, who's minding the store and how are we going to take care of these issues?"

Watch CTV News at Six for a full report from Mi-Jung Lee