Daphne Valiquette is the main villainess from "18-5-4," a second season episode of The Mentalist.
She was played by Lucy Davis.
Daphne Valiquette is the wife of computer genius, Noah Valiquette, who invented the Code Breaker, a universal hacker that can gain access to any computer. She was unhappy in her marriage to Noah, due to lack of intimacy between the two, and the fact that Daphne herself was living on meager tips as a waitress, while Noah had no income. Daphne figured that the Code Breaker would bring in millions once Noah sold the device, but Noah refused to sell in fear that the device would end up in the wrong hands.
Noah's refusal to sell was the last straw for Daphne, as she planned to kill her husband. Knowing full well about Noah's fear of clowns, Daphne dressed up as a clown (after placing an ad about a clown convention) and pursued Noah at a park, where she shot and killed him. After killing Noah, the crazed villainess cut off Noah's index finger, planning to use his fingerprint to open a safe that she believed the device was in. It was actually at the home of Tolman Bunting, and it was while testing the device that Daphne was revealed as the killer. The test showed that the device wasn't working, but Daphne flipped a switch which activated it--only for the words "My wife killed me" to be shown repeatedly. After confessing to the murder, Daphne was arrested.