The Dark Is Death's Friend (1975)

Sinopsis: Giorgio Mainardi, a womanizer, plans to rid himself of his wealthy wife Norma. He happens to see a sinister figure disposing of a body and seizes the opportunity to make a deal in which the killer will murder Norma. The deed is done but a young couple, Luca and Laura, unwittingly steal the killer's car, complete with Norma's corpse in the boot. They head for the beach and break into an abandoned old house. The killer tracks them down and while Luca is out having sex with a blonde stranger, he terrorises and rapes Laura. When the young man and the blonde turn up for a threesome they are both quickly despatched. After a struggle, Laura manages to fatally wound her attacker. Back in the city, the police become increasingly suspicious of Giorgio Mainardi...