Authorities in South Korea believe Yoo Byung-eun owns the ship and that his alleged corruption might have contributed to its sinking. Authorities have been after Mr Yoo for weeks and are offering a £300,000 reward for tips about where to find him.
Mr Yoo is a member of a church group called the Evangelical Baptist Church, which critics say is a cult.
Police say officers detained four church members for allegedly providing shelter for Mr Yoo or helping him flee during their raid on the sprawling compound outside Seoul. Another church member was detained for allegedly trying to obstruct the raid.
The move came a day after 15 members of the ferry's crew went on trial.