Tinian Dynasty Hotel and Casino’s failure to report its casino activities has cost the struggling resort millions in penalties.

The U.S. Attorney for the Districts of Guam and the Northern Mariana Islands recently announced that it has forfeited $2.5 million from Hong Kong Entertainment Investments Ltd., which operates Tinian Dynasty, Marianas Variety reported.

“This forfeiture is the culmination of a year-long investigation. The persistent and dedicated efforts of IRS criminal investigators were instrumental in recovering these funds,” U.S. Attorney Alicia A.G. Limtiaco said in a statement.

In July 2015, both parties entered into a non-prosecution agreement that required Tinian Dynasty to “administratively forfeit $536,969.12” in addition to the $2.5 million indicated in the U.S. district court’s final order of forfeiture. The amount is said to be the largest forfeiture ever collected by the United States in the Northern Mariana Islands.