The Watcher in the Attic

江戸川乱歩猟奇館 屋根裏の散歩者

Also known as La maison des perversités, Watcher in the Attic, 江户川乱步猎奇馆：屋脊里的散步者, Edogawa Rampo ryôki-kan: Yaneura no samposha, The Stroller in the Attic

When a tenant from a shabby 1920s boarding house secretly witnesses the landlady perform a truly heinous act, he is overcome with desire for her and begins plotting to kill a fellow tenant to demonstrate his love.