Ann Ostilow (Jennifer Van Dyck) is a hidden villainess from "Sick," episode 5.19 of Law & Order: SVU (airdate March 30, 2004). She is the wife of Jeremy Ostilow and the mother of siblings Jeremy Jr. (JJ for short) and Lisette.
Ann first appeared along with her husband when Detectives Elliot Stabler and Olivia Benson entered her house due to JJ posting online messages about raping and murdering a 5-year-old girl, along with threatening to kill any police officers who came to stop him. During a one-on-one confrontation with Benson, Ann claimed that JJ had no obsession with violence, and in response to questions about him harming Lisette, the villainess stated that her son loved his sister and he would say so if asked. However, it was revealed that JJ had a history of having violent thoughts and anger issues over anything and anyone plaguing him—including Lisette, who revealed that her brother mutilated the private parts of several of her dolls.
Stabler suspected that JJ had all the signs of a victim of sexual abuse, and after being committed to a psychiatric hospital, he was interviewed by Dr. George Huang. JJ revealed the truth to Huang: he was molested by a man he only referred to as "Billy," while his parents covered it up and were paid off. After that, "Billy" was revealed as William Tripley, the owner of Tripley Toys—where Jeremy once worked. The molestation took place three years prior to the episode's events when JJ was just nine, and afterwards, he informed his parents about what William had done to him. Shockingly, however, both Ann and Jeremy turned heel and accepted a $4 million payout from Tripley for their silence as well as their son's. The greedy couple covered up their callous deed for three years and also agreed that the only way they could keep their ill-gotten money was to make sure JJ never went public about being molested.
William was brought to trial afterwards, but later in the episode, JJ was shown on video recanting his statement, leading to Benson and Stabler confronting his villainous parents at their home. Upon seeing the pair, the evil Ann lashed out and told them to lower their voices regarding her and her husband's actions since people could hear what they were talking about. The confrontation ended with an angry Jeremy slamming the door in the detectives' faces, which was followed by him being arrested and jailed when he refused to reveal his son's whereabouts. Tripley ended up being acquitted in not only JJ's case, but a similar case involving April Hodges due to the fact that April herself was used by her grandmother as part of a monetary scam. Regarding Ann, however, her fate was never revealed.