4 Moscas sobre terciopelo gris

The drummer of a rock and roll band Roberto Tobias (Michael Brandon) sees a man wearing sunglasses stalking him everywhere. He follows the man to a derelict opera house and when he confronts the stranger, he pulls a knife. However Roberto accidentally stabs him in self-defense and the man falls from the stage to the floor. Out of the blue, a spotlight is turned on and Roberto is photographed in the crime scene by a masked person on a theater box. Roberto leaves the place and returns home. On the next morning, he reads the newspaper the news about a stranger called Carlo Marosi that was murdered. During the night, Roberto and his wife Nina (Mimsy Farmer) welcome friends and Roberto finds a photo of the previous night entwined with his vinyls. He tells the truth to Nina and their maid Amelia (Maria Fabbri) overhears the story. While Robeto meets his friend Godfrey (Bud Spencer) to ask for help, Amelia schedules an encounter in the park with someone to blackmail with the photos she had found in the apartment; however Amelia is murdered in the park Meanwhile Nina's cousin Dalia (Francine Racette) arrives to stay with Nina. But soon Carlo Marosi appears eating at a restaurant and calling someone to meet him. What has happened in the opera house?

"4 mosche di velluto grigio" is a flawed film with am intriguing title. The atmosphere is suffocating most of the time; the camera work uses unusual angles and positions; the cast has good performance. But the plot point with the identity of the killer is weak and quite senseless. My vote is six.

Title (Brazil): "Quatro Moscas Sobre Veludo Cinza" ("Four Flies on Grey Velvet")