A man thought to be a suspect wanted for one of a series of terrorist bombings in Japan in the 1970s died Monday morning, an investigative source said.

The man recently confessed to being the alleged bomber Satoshi Kirishima, who was a member of an extreme left wing group. He was undergoing treatment for terminal stomach cancer at a hospital in Kamakura, Kanagawa Prefecture, and was confirmed dead at 7:33 a.m., according to the source.

Police are planning to carry out DNA analysis to confirm the man's identity, and if confirmed, turn over the case to prosecutors with the suspect having deceased.