|Minor Character: Las Vegas|
|Name||Catherine "Katy" Hill|
|Family|| Bo Mattison (father; deceased)|
Unnamed mother (deceased)
|Pathology|| Serial Killer (originally)|
Spree Killer (later)
|Portrayed By||Natalie Hall|
|First Appearance||Last Woman Standing|
"Last woman standing. How does it feel?!"
Catherine's father was Bo Mattison, a high-stakes poker player who by 1997 was almost broke. That year he took part in the Palermo Poker Classic and played against three other poker experts, Ed Ficelli, Trent Alridge and Peter Coe. What he didn't know was that his opponents, led by Ficelli, and the card dealer were all in collusion to help each other beat him. Peter Coe finished him off. A week after losing, Bo killed himself in a park. Catherine went on with her life until shortly after her mother died, when she found letters written by her father revealing that he figured out that he had been cheated. She planned to take revenge on the people behind the scam and took a job as an assistant for a stage magician named James Nefarro, a.k.a. "Dr. Jimmy", who had paid Peter Coe's entrance fee into the tournament. On December 19, 2012, she murdered Ed Ficelli with a heroin overdose in a pattern resembling the four of clubs.
Posing as an S&M dominatrix, Katy murdered Trent Alridge by stuffing seven chicken hearts down his throat with a funnel. That same night, she murdered Peter Coe by throwing an Ace of Spades (specifically taken from a deck created for the 1997 Palermo Poker Classic) into his throat. A few nights later, after doing a rehearsal with Dr Jimmy that is interrupted by the CSI, she murdered Ava Rendell by decapitating her with a medieval warhammerr Dr. Jimmy had ordered for his show.
Satisfied that her plan was in place, Katy abducted James Nefarro and stuffed him in an iron maiden with a spade-like dagger pointing at his throat. The CSI team arrive to find Dr. Jimmy, and she claimed that he had fled and pointed them to the ax. She then took his car to the playground where her father had hung herself, with a spade in the trunk to trick the police who soon arrived.
At the platyground, she encounters Morgan Brody, who has deduced her motive. Katy breifly rants to Morgan before agreeing to show her where James was buried. However, Morgan figures out that it's a distraction and gets Nick to save Dr. Jimmy from her real trap. Her plan ruined, Catherine tries to shoot Morgan but is shot dead in response.
"You want me to show you my cards?"
Katy targeted the people who had scammed her father. She killed them in widely-varying ways, each representing a card of the last five dealt cards on which her father lost.
- December 19, 2012: Ed Ficelli (the ringleader; killed with a heroin overdose spiked with trifolium clovers; represented "four of clubs")
- February 27:
- Trent Alridge (one of the players; asphyxiated by stuffing seven chicken hearts down his throat; represented "seven of hearts")
- Peter Coe (one of the players; slashed his throat by throwing a playing card at it; represented "ace of spades")
- Ava Rendell (born "Ava Heidbredder"; daughter of the dealer in the game; decapitated with a medieval warhammer; represented "king of diamonds")
- February 28:
- James "Dr. Jimmy" Nefarro (accomplice in the scam; attempted to kill with an iron maiden; represented "king of spades")
- Morgan Brody (attempted to shoot)
- February 27: