House on the Edge of the Park (1980)

A posh couple experience car trouble on their way to a villa party and stop into a local mechanic's shop for assistance, unaware of his shady background. After he and his mentally challenged assistant fix the car, the couple invite them to the party to return the favor, leading to an evening of mayhem.

Directed by: Ruggero Deodato

Starring: David Hess, Annie Belle, Giovanni Lombardo Radice, Lorraine De Selle, Christian Borromeo, Marie Claude Joseph

Links: IMDb, Movie posters, Movie stills