Five human bodies and two heads were found on a 'ghost boat' on the shore of a Japanese island.
The heavily damaged vessel washed ashore on Sado Island, northwest of the mainland, on Friday and police waited to board the boat until Saturday due to unstable weather, the Japan Times reported.
Coast Guard official Kei Chinen couldn't confirm whether the heads belonged to any of the five bodies or were from two other people, but said their deaths are under investigation.
He added that the wooden boat had letters and numbers in Korean on the outside of the hull.
This discovery is the second time since November a wooden boat has washed up on Sado Island, Chinen said.
According to the BBC, 'ghost boats' washing up on Japan's shores are believed to come from North Korea, and are often empty or contain only human remains.
Speculation from previous incidents say that people found on the vessels are defectors or spies from North Korean leader Kim Jong-un's regime.
It is also thought that poverty is forcing North Koreans to fish further afield.