A man watches a TV news program showing a reward poster for fugitive billionaire Yoo Byung-eun at the Seoul Train Station in Seoul, South Korea. Pic: AP.

SEOUL, South Korea (AP) — Thousands of South Korean police officers have stormed a church compound in their hunt for a fugitive billionaire businessman over April’s ferry sinking that left more than 300 people dead or missing.

Authorities believe the businessman, Yoo Byung-eun, owns the ship and that his alleged corruption may have contributed to its sinking. Authorities have been after Yoo for weeks and are offering a $500,000 reward for tips about him.

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 Yoo or helping him flee during their raid on the sprawling church compound outside Seoul on Wednesday. Another church member was detained for allegedly trying to obstruct the raid.