Continuity mistake: While Jessica and Mike are at the bar to get information about the second victim, when she grabs the bartender and shows him both photos, the way she holds them changes between shots depending on the angle. (00:46:20)
Continuity mistake: While Dr. Frank is explaining to Jessica that their session is standard procedure for any cop who's been through a traumatic experience, he's holding both his pen and eyeglasses in his left hand, but in the closeup the pen is suddenly lying on the writing pad by his right hand. (00:15:00)
Continuity mistake: When Jessica finds the gift box of roses outside her apartment, there's a closeup of the card signed "Ray", then a few shots later in the next closeup of the card the signature "Ray" is entirely different. (00:56:00)
Answer: He killed the parents because the mother was sleeping around and it was driving the father insane. He began killing Ashley Judd's lovers because he could see she was becoming like her mother.