Erotic Games of a Respectable Family(1975)

Professor Ricardo Rossi is an uncompromising moralist and a paladin of Catholic morals. He is understandably baffled when he finds his wife Elisa in bed with another woman (whom Rossi mistakens for a man). Furious, he poisons his wife and throws her body into a lake, then brings home a prostitute, Eva, to replace her. He also begins an affair with his niece Barbara. But Elisa is not dead, as Rossi soon finds and she is plotting with Eva to get rid of him. Rossi is more precise this time and shoots the two women dead. However, there is a complication and more deaths ensue...