By Isabella Cota

SAN JOSE, Costa Rica (Reuters) - Costa Rica said on Thursday it was investigating two men suspected of laundering money for Venezuelan government firms after detecting a shady scheme to buy millions of bars of soap.

Investigators in the Central American nation said they had frozen at least $15.5 million in bank accounts belonging to a Costa Rican lawyer and a Venezuelan who had made suspicious transactions for a company owned by Venezuela's government.

Police raided the premises of the lawyer and the hotel room where the Venezuelan was staying to gather evidence, but made no arrests, the country's judicial investigation agency, a unit of the attorney general's office, said in a statement.

"The suspicion is that bank accounts are being created in Costa Rica to launder money in the United States and other countries, from companies belonging to the Venezuelan government", the statement said.

Venezuelan government officials were not immediately available to comment.

Costa Rican investigators believe the two men also created other companies to launder money coming from Venezuelan government-owned firms. The agency did not name the companies.

According to the Costa Rican agency, a bank in Costa Rica detected a suspect transaction on June 13 in an account belonging to a company that lists the Costa Rican lawyer as a general manager and the Venezuelan as a counter-signatory. The men were not named.

The two associates had submitted paperwork for the receipt of $9.7 million from a Venezuelan state company for the planned purchase of 10 million bars of soap, the agency said.

But police findings showed international transactions were far higher, with $15.5 million deposited, it added.

Investigators said last year that several million dollars were deposited internationally to accounts belonging to the two men for planned purchases, but the money was instead deposited to bank accounts in the United States, China and Panama.

(Additional reporting by Daniel Wallis in Caracas; Editing by Dave Graham and Leslie Adler)