I am looking for a title of a movie where a stepmother and a stepdaughter have sex on top of a kitchen counter which knocks several pots and pans on the floor. The scene ends with them making love on the bed. After they make love, the step mother decides that the stepdaughter shouldn't have anyone else but her so she kills the best friend of the stepdaughter. The movie ends with a policeman killing the stepmother while she is trying to kill the boyfriend. Here is a picture of the stepdaughter.