SEOUL, April 23 -- South Korean prosecutors on Wednesday raided the office of the sunken ferry operator, the owner's house and related affiliates, local media reported.

Inchon prosecutors' office has been investigating alleged corruption of the ship's owner, Yoo Byung-eon, and his family members.

Cheonghaejin Marine, the operator of the ferry Seowl which capsized near Jindo island off the country's southwest coast on April 16, has been under suspicion that it had illegally modified the ferry to raise its passenger capacity and overloaded freight.

Investigators raided some 20 places, including Yoo's house, companies and religious communities linked to Yoo, to search and seize documents and related data.