Kelly Manning, aka Ann Wilson (Debra Sandlund) was a hidden villainess from "The Black Widow," episode 3.10 of Matlock (airdate February 14, 1989).
She was the wife of Ken Wilson, but seven years prior to the episode's events, she colluded with her brother to fake her murder and run off with her $1 million insurance. As a result of her villainous plan, Ken ended up serving seven years in prison for the "murder" of his wife.
Meanwhile, the evil Ann changed her name to Kelly Manning and began working in a real estate office, serving as part owner, while making off with her ill-gotten money. After his release, Ken found out about Kelly sending checks and went to the office to meet her, only to recognize her as Ann. Ken realized his wife's evil deeds when he found the necklace he gave her as a wedding gift, and when he confronted her, Kelly denied ever knowing him, claiming that Ken had made a mistake. Later on, Kelly was stabbed to death in her home by Bob King.