Story highlights At least 12 wooden boats have been found adrift off Japan recently

Authorities believe the boats may have come from North Korea

(CNN) Four bodies have been found inside a capsized boat discovered floating off the north coast of Japan's main Honshu island -- the latest of the so-called "ghost ships" washing up in Japanese waters in recent weeks.

The vessel -- a 12.5-meter long wooden boat -- was found on Sunday 10km (6.2 miles) south of the Ushitaki fishing port in Sai Village, Aomori prefecture, a spokesman for the Aomori Coast Guard told CNN Monday.

Though there was nothing to definitively identify the boat, it looks very similar to boats found in October in the same region, which featured Korean "Hangul" lettering and markings on their hull, he said, adding that they may have come from North Korea.

Japanese coast guard pull the wooden boat from the water.

The condition of the latest boat indicated it may have been drifting for some time, he said.

Chilling cargo

Read More