U.S. authorities raided the office of casino operator Imperial Pacific International Holdings Ltd. in Saipan, seizing several documents related to its integrated resort project in the Commonwealth of the Northern Marianas Island.

Bloomberg reported that the U.S. federal agents, together with the Federal Bureau of Investigation, swooped down on Imperial Pacific’s office last week, although no one really knows what their business was.

The FBI neither confirmed nor denied the agency’s participation in the raid as part of its legal policy but the agency did give a hint that it was probing Imperial Pacific when it stated that “public corruption is the FBI’s top criminal investigative priority.”

“Elected or appointed officials are entrusted and expected to protect the interests of the people with integrity. When that trust is betrayed, the security and stability of our government is put at risk. Anyone with information about a potential violation of federal law is asked to contact the FBI,” the FBI said in a statement to the news outlet.