The Devil's Path.

Death-row inmate Sudo sends a letter to magazine reporter Fujii. In his letter, he states that a man named Kimura, also known as "teacher," committed numerous murders for insurance money. While checking out the story, based on Sudo's tip, Fuji becomes convinced that the letter is correct. But, a lot of time has passed from the incidents and Sudo's testimony isn't clear. Due to the persistance of Sudo, who is a former yakuza, and Fuji, the police begin to move.