Deborah Vandenhey (Deanna Dunagan) is the true main villainess from "Shaken," the antepenultimate episode of Proven Innocent (airdate April 26, 2019). She is the matriarch of the wealthy Vandenhey family; the mother of Clay Vandenhey and the grandmother of Declan (from Clay's first marriage) and Amelia Vandenhey (from Clay's second marriage).
Amelia died ten years prior to the events, with the original investigation determining that she had Shaken Baby Syndrome. After it was uncovered that Amelia's mother, Gabrielle Parcell (Clay's second wife), had postpartum depression, Gabrielle was arrested and convicted of killing her daughter--especially after it was uncovered that Gabrielle was distant towards Amelia. However, during her first interview with Madeline Scott and Ezekiel "Easy" Boudreau, Gabrielle stated that her illness made her overly cautious of what she could be capable of regarding Amelia, and she ardently took her medication.
In Deborah's first appearance, she lashed out at Madeline and Easy for their defense of Gabrielle, not only referring to her ex-daughter-in-law as a murderer, but referring to Gabrielle's sister, Kristen, and the rest of her family as "trash." An investigation into Amelia's death revealed abuse, and it was originally indicated that Clay was abusive towards his daughter, but it was Clay's first wife who revealed the true abuser as none other than Deborah. In addition, Deborah's abuse dated back decades, as she regularly beat Clay when he was a child, and even paid Clay's pediatrician to cover up the abuse. A more recent incident revealed that Deborah often punished Declan by twisting his arm and even breaking it, and she would cover that up by claiming that Declan broke his arm while horseback riding.
Deborah angrily confronted Madeline and Easy after they got the truth from Clay, accusing them of bullying her son and threatening to sue them. She was suspected of killing Amelia, but it was later revealed that the true (accidental) killer was Declan, who admitted to it when he was confronted by the pair. Declan testified that while he was watching a video, Amelia's crying annoyed him, leading to Declan pushing the high chair she was sitting on. As a result, Amelia's head struck the wall, killing her instantly, and when he asked his grandmother if he was responsible for what happened, the evil Deborah responded by manipulating her eight-year-old grandson and stating that Gabrielle was to blame, as she didn't want Amelia.
Deborah left in disgust after Gabrielle was exonerated, but she was stopped by Judge Greer, who reminded her that while she can't be prosecuted due to the statute of limitations, she would be judged harshly by the court of public opinion. Afterwards, Deborah was shown being bombarded by a barrage of interviewers; part of her humiliation after her past evil actions were uncovered.
- The cancellation of Proven Innocent after one season makes Deborah Vandenhey the series' final villainess.