The state-backed Industrial Revitalization Corp. of Japan has launched an investigation into a suspected secret deal between Daiei Inc. and U.S. investment fund Colony Capital LLC over the sale of the Fukuoka Daiei Hawks ballclub, according to sources.

Daiei had expressed its intention to retain ownership of the Fukuoka-based Hawks, but is now considering selling most of its stake to Softbank Corp., which has expressed a desire to purchase the Pacific League baseball team.

IRCJ, which is in the process of mapping out a rehabilitation plan for the ailing retailer, has decided to ask Daiei to disclose pertinent information on the grounds that the sale of the ballclub constitutes a major change in Daiei's business plan, the sources said Thursday.

The sources said IRCJ suspects that Daiei might have made a secret deal with Colony, which owns the Fukuoka Dome and the rights to hold the Hawks' games.

It is possible that Daiei and Colony agreed on such details as the price of the ballclub and conditions of the sale, the sources said. Daiei holds 98 percent of the Hawks' shares, but is considering lowering its stake to about 20 percent by selling a majority of its shares to Softbank.