Death Screams (1982)

Late one night, a young couple are brutally murdered at a make-out spot by an unseen assailant, their bodies tossed into the nearby river. As the lifeless lovers drift slowly downstream, the residents of the town excitedly prepare themselves for their annual carnival, unaware that a machete-wielding maniac with a twisted grudge is lurking in their midst. When a group of teen revellers plan a late-night after party down in the local cemetery, they unwittingly set the stage for a bloodbath.