A probe by investigators in the United States is attempting to determine if Englewood, Colorado-based money transmitter, Western Union was aware of gambling transactions by its agents in Costa Rica and other Latin American countries, the company revealed in an annual filing with regulators on Friday.

The government is investigating “concerns the company was aware there were gaming transactions” and that the company “failed to take proper steps to stop the activity,” the company stated in the filing, adding that the company could face significant fines if the government brings money laundering charges against the company.

The document mentions transactions originating to and from Costa Rica, as well as Nicaragua and Panama. References were also made to transactions involving Haiti, the Philippines, Vietnam, the Dominican Republic, Peru and the Bahamas.   Most of the transactions under investigation are from the years 2013 and 2014.

Costa Rica is home to perhaps the largest concentration of online sportsbooks and casinos in the Americas, if not possibly the world. Western Union is commonly used as a method for customers in the United States, where online gambling is illegal, to make deposits and withdrawals from accounts with such firms.

Western Union locations in Costa Rica and other countries outside the United States operate as “licensed agents,” similar to franchisees.

Speaking exclusively to The Costa Rica Star on Monday, a former high-level executive for a large online gambling operator in Costa Rica explained how some licensed Western Union agents worked hand-in-hand with online gambling companies in Costa Rica.

“The [Western Union] agent would provide our company with a list of hundreds of different names – random names – to use for a given month, names to which customers in the United States would send Western Union transfers. The [Western Union] agent kept track of which names “belonged” to us or other gambling operators. When we had exhausted that list of names, after each name had received the monthly limited imposed by Western Union, they would give us a new list. So, essentially, customers in the US would send a Western Union to a name, like “John Doe Watson” in Costa Rica, and we would receive credit from the Western Union agent. All of the transactions sent to our list of names were added together at the end of the month, and the Western Union agent would write us a single check for all of those transactions. We had several agents in Costa Rica and other countries as well. In the early days, the names were from phone book pages. They would rip say 5 pages from a phone book, photocopy them, keep one copy and give us the other copy. Those were our names [under which to receive transfers] for the month,” the former gambling executive said on condition of anonymity. “Later they got a little more sophisticated and would just email our accounting department the list of names to use that month.”

Western Union on Friday said it was cooperating with the investigation.

Some 50 Western Union agents in Costa Rica, Nicaragua, and Panama are apparently implicated in the probe.