South Korea is offering a reward for information about a mysterious missing billionaire who authorities say owns a ferry that sank last month, leaving more than 300 people dead or missing.

A distress call believed to be the first made from sinking South Korean ferry was made by a boy with a shaking voice, three minutes after the vessel made its fateful last turn.

The captain of the South Korean ferry that capsized off the southwest coast was facing a criminal investigation amid unconfirmed reports that he was one of the first people to jump to safety as the vessel began sinking.