She was played by Talia Balsam.
Tonya Gilpin is the head of a dating service company known as Perfect Couples, but she is also an evil murderess looking to cash in on a life insurance policy from her ex-husband, Ralph Trager. She was to receive a million dollars in the event of Ralph's death, but a clause stated that if Ralph committed suicide within two years of the policy, the insurance policy wouldn't have to pay Tonya. Exactly a year and 11 months after that, Ralph hung himself, just to keep Tonya from receiving the benefits. To get what she felt was hers, Tonya resorted to committing murders, killing two victims in the same manner as Ralph's suicide, planning to have his death ruled as a homicide so she could collect.
In the episode's climax, the evil Tonya attacked Amanda Bentley and planned to kill her as well, doing so after Amanda found Ralph's suicide note and showed it to Tonya at her home. Tonya tore up the note and tied up Amanda, and later produced a gun with intent to shoot her and make it look like a suicide. At that moment, Tonya's evil plan is thwarted by Steve Sloan, who entered the home and arrested the villainess for the murders, as well as attempting to kill Amanda.