Someone's Knocking at the Door (2009)

The shocking news of the gruesome, sex-related homicide of medical student Ray Harris spreads like wildfire in the Linda Vista Community Hospital, where the brutally slain student was found in his dorm. Was it a deviant S&M game gone horribly wrong or is a deranged campus sex killer lurking somewhere out there? Soon, as the police investigation continues, a strange connection between the highly experimental hallucinogen "Taldon" and the peculiar 1973 case of John and Wilma Hopper emerges, while Ray's friends, one by one, start being stalked by an obscure pair of insane sociopaths with only one intention: to ravish them to death. Before long, the bright red blood will flow fresh and warm, so, how could one escape when the obscure enemy lives inside his head? Or maybe he doesn't?