Yami no Bansosha

A year after manga master Fumiya Ajima's death, 50 unpublished sketches are discovered. The sketches appear to be the work of Fumiya Ajima, but the sketches show details from several missing women cases that occurred 35 years earlier. Fumiya Ajima’s wife asks the Department Head of Ajimapuro to find out if the sketches are the work of her late husband. Ex-police officer Yuki Mizuno receives a request to investigate the origins of the 50 sketches. Yuki Mizuno then enlists the help of Shinji Daigo, an expert in the manga world.
(Source: AsianWiki)