Four Flies on Grey Velvet (Italian: 4 mosche di velluto grigio) is a 1971 Italian giallo film written and directed by Dario Argento. The film is the third in director Argento's "Animal Trilogy", which started with The Bird with the Crystal Plumage and The Cat o' Nine Tails.
Roberto Tobias (Michael Brandon) plays the drums for a local rock and roll band when at various time, he sees a man in dark sunglasses wearing a suit and tie, watching him. After the session, Roberto follows the man through the dark streets to an apparently abandoned opera house where he confronts the man and asks him why he's been following him for the past several weeks. The man declines such actions and pulls a knife on Roberto when the drummer gets too close. In the struggle, the man is accidentally stabbed and he falls from the stage to the lower level. Suddenly a spotlight is turned onto Roberto and a masked person on the balcony snaps some photos of Roberto holding the bloody knife.