The Fifth Cord (Italian: Giornata nera per l'ariete; also known as Evil Fingers and Silent Killer) is a 1971 Italian giallo film directed by Luigi Bazzoni. The Italian title, which in its literal meaning reads "Black Day for the Ram", in its typical figurative meaning could translate as "A Bad Day for Aries", reprising Dario Argento's practice of using animals in the titles of his thriller films. The film is based on a novel with the same name by D.M. Devine. AllMovie called it an "outstanding giallo thriller".
(Summary from Wikipedia)