Darkroom (1989)

He kills at the blink of an eye.

Janet has just returned home from college to visit her conservative family at their remote farmhouse, nestled deep in the countryside. What should be a happy reunion is quickly disrupted by the arrival of an unexpected guest: a mystery killer who photographs their unsuspecting victims before murdering them in a variety of brutal ways. As her family and friends are picked off one by one, Janet is forced to fend off the mysterious maniac, all the while uncovering unsettling secrets surrounding her family’s violent and perverse past…