Rent I Drink Your Blood (1970)

A group of hippies calling themselves the Sons and Daughters of Satan arrive in a deserted town and viciously attack a young girl named Sylvia (Iris Brooks) and her grandfather Doc (Richard Bowler), who tries to confront them. When he fails, Sylvia's brother Pete (Riley Mills) sets about getting his own revenge on the hippies by infecting the local bakery's meat pies with rabies, setting off a chain of event that causes a crazed epidemic that infects most of the town and causes the afflicted to attack the survivors.