Giallo in Venice (1979)

Venice: The bodies of a married couple, Flavia and Fabio, are discovered on the dockside. She has drowned and he has been stabbed to death with a large pair of scissors. Marzia, Flavia's best friend, is questioned by the police and a chain of slaying is set in motion. The victims include a prostitute who is stabbed in the crotch; Marzia's lover, who is shot in the kneecaps before being doused in petrol and set alight; and Marzia herself, tied to a kitchen table and dismembered, before being stuffed in a fridge. Meanwhile, extended flashbacks reveal that Fabio gained perverse pleasure from forcing his young wife to take part in degrading sexual acts...