Movie about creepy neighbor with a hole in his stomach

Ok so this movie haunts my friend and I, it’s a horror/thriller about this couple who slowly realize their neighbor is a psycho. The neighbor is a white guy, he breaks into their house and poisons the food in their fridge… he also audio records the couple being intimate and literally gets down with himself via a literal HOLE WOUND IN HIS STOMACH… and at another point he unplugs the oxygen machine of an old person. Can anyone tell me what that movie is!!??