A Night to Dismember on AllMovie

As Detective O'Malley (played by an uncredited actor, lucky guy) tells it, the entire Kent clan is slayed one at a time by a hatchet-wielding maniac that may be Vicki Kent (Samantha Fox). Vicki is back after having spent time in an insane asylum for murder, so it wasn't a very good idea for her brother Billy (Bill Szarka) and sister Mary (Diane Cummins) to try to drive her crazy so she'd be returned to the institution. As O'Malley follows the trail of bodies, he comes to believe that perhaps Vicki isn't the murderer after all.