Name of a Thriller flick from early 80's??

Question

It was on or before 1983. It was about a serial killer, who killed women, but he would make them say "i love you" and stuff. and in the end he was in an Orgy type place, and he had a chick on a waterbed and made her say "i love you" over and over, and he didn't believe her, so he killed her and the water went everywhere..
Not that it was a good flick, but i remember seeing it A LONG time ago, and amc had it on a couple months ago, and i can't remember the name.

Answer 1

Try "Pieces"
imdb.com/title/tt0082748

Answer 2

I also saw that flick, but I can't remember the name so it can't have been that good!