Cindy Garrett
Cindy Garrett is the main villainess from "Till Death Do Us Part," episode 6.03 of Diagnosis Murder.

She was played by Staci Keanan.

Cindy Garrett is the daughter of wealthy Wayde Garrett, and in the episode, Cindy and her soon-to-be husband, Philip Cobler, were planning to kill Wayde and frame his wife (and Cindy's stepmother), Denise, for the murder, which would result in Cindy inheriting Wayde's fortune. The episode begins with the villainous couple planning the murder and frame-up, and the first half shows everything going according to plan--in their mind. The plan included Philip planting a book about the effects of certain prescription drugs, as well as poisoning Wayde's wine with phenelzine, while Cindy plants the same drug in Denise's purse. During the wedding reception, Wayde begins succumbing to the effects and later collapses and dies while dancing with Cindy. Following the murder, the evidence against Denise is found by Steve and Mark Sloan, leading to Denise's arrest.

The second half showed the actual events, and the couple stumbling through their murderous plot. Philip's attempt to plant the book led to a number of them falling, and he spilled the poisoned wine, which the family dog lapped up. Cindy successfully planted the drugs in Denise's purse, but she was surprised to see Denise with a different purse at the reception. The couple had to make a second attempt to poison Wayde, and it was successful. After the murder, Denise ended up arrested due to the evidence being planted on her.

However, the family dog having the phenelzine in his system ended up being Cindy and Philip's undoing, and after Steve informed them about the wedding photographer taking a photo that could prove Denise's innocence, the couple attempted to take the photo and destroy it, only for Mark and Steve to catch them in the act. Cindy and Philip ended arrested, with the villainess chastising her husband over their plan's failure.