Ellen Huffner (Anne Kyle) was a villainess from "Delinquent", the penultimate episode of Law & Order: SVU's twelfth season (airdate May 11, 2011). She was the former babysitter of Hunter Mazelon (the episode's main antagonist), with Hunter having been her charge when he was seven.
The episode's climax also revealed Ellen to be a villainous molestor, as she was revealed to have sexually abused Hunter during her time as his babysitter, even forcing the young boy to perform sexual acts on her. Hunter's mother, Bree, eventually learned about the abuse months afterwards, but ultimately decided against pressing charges out of the belief that Hunter could forget about Ellen's abuse in time. Instead, however, the trauma from his molestation led Hunter to become a serial rapist/murderer, namely targetting women around the same age that Ellen was when she abused him.
The episode's events had Hunter being brought in by SVU after he was caught hiding in the closet of Annie Meyers, with the episode's progression revealing Hunter's history as a serial rapist/killer. Hunter's victim pattern led the SVU team to believe that Bree had molested Hunter, only for her to later reveal Ellen as Hunter's true abuser and how she hadn't reported her to the police out of a belief that she was protecting Hunter. After realizing that Hunter might have fled to her apartment after escaping police custody earlier, Elliot Stabler and Olivia Benson went to Ellen's apartment, only to find Ellen and Hunter lying on the floor in a puddle of blood, both appearing dead. But as the detectives entered the scene, Hunter awoke and revealed that he was remorseful for attacking his other victims and believed confronting Ellen would make him stop killing. But upon being confronted by her former victim, the evil Ellen refused to tell Hunter why she molested him, leading Hunter to kill his abuser by shooting her in the head.