For decades, the smiling mugshot of Satoshi Kirishima has featured on wanted posters outside police stations across Japan.
After 49 years on the run, authorities think they may have got their man.
A patient at a hospital near Tokyo has claimed he is Kirishima, a member of a militant group behind several deadly bombings in the 1970s.
Police are waiting for DNA tests on the man, who was admitted under a different name suffering terminal cancer.
Police have made contact with the man and are now working to confirm his identity.
He had belonged to the East Asia Anti-Japan Armed Front – a radical, left-wing organisation believed to be behind several bombings against companies in Japan’s capital between 1972 and 1975.
Eight people were killed in one attack committed by the group at the headquarters of Mitsubishi Heavy Industries in 1974.
Japan’s National Police Agency says on its website that Kirishima violated “criminal regulations to control explosives”, and is wanted for “serial bombings of companies”.
Kirishima is alleged to have help plant and detonate a homemade bomb that destroyed part of a building in Tokyo’s Ginza district in one particular attack on 18 April 1975, according to local media.
After 49 years, Kirishma, who would now be 70, may have finally been located.
He initially used a different name when checking into a hospital in Kamakura City in Kanagawa, south of Tokyo.
But he told hospital officials on Thursday he was actually Kirishima, saying he wanted to use his “real name” in his final moments as he only has a few months left to live, according to reports.
Police are now carrying out DNA tests to confirm his identity, describing his possible re-emergence as a bolt out of the blue.