Blood Stains in a New Car(1975)

Original title: Manchas de sangre en un coche nuevo

Driving home in the brand new Volvo his wealthy wife gave him for his birthday, Ricardo comes upon a smoking, overturned auto with a man and boy trapped inside but, afraid he'd get bloodstains in his new car, he ignores their cries for help and drives away just before the wreck explodes. Soon after, blood begins pooling in his backseat and Ricardo comes to know how Lady Macbeth felt when he can't get the damned spots out no matter how many times he cleans the car...