Elizabeth "Liz" Grayson (Chad Morgan) is a villainess from "Obsession", episode 3.13 of CSI: NY (airdate January 17, 2007). She appeared as a suspect in the death of real estate agent Alex Martin, who was found stabbed to death in his home along with evidence suggesting to the CSI team that he had kidnapped a brunette woman and held her captive.
Evidence was discovered indicating that Alex forced his hostage into his trunk, and horse hairs in the trunk traced the hostage back to a horse stable where Liz owned a horse named Harley; the only horse taking the same medications found in traces on its' hairs. Liz was initially believed to have been kidnapped, but after Lindsay Monroe discovered traces of strawberries and champagne were found on the duct tape used to gag Liz, the team began to suspect Liz's "kidnapping" was actually part of a sex game between her and Alex.
This theory appeared to be debunked when Liz was later located after she checked herself into Sacred Cross ER, where she stated to Stella Bonasera as she examined her that she had been kidnapped from the stables and held captive by Alex, later telling Mac Taylor that Alex wanted money from her and that she eventually used his own knife to kill him in self-defense after he raped her, claiming she hadn't known he was dead afterwards and disposed of the knife in a trash can as she was running away. However, Mac confided in Stella that he believed Liz to be lying, as the forensic evidence poked multiple holes in her claims. Her rape kit also revealed that Liz had sex with a man after supposedly being raped by Alex, leading to the reveal of Alex's true killer: Terry Rockwell, Liz's ex-husband.
As Liz admitted when brought in for interrogation by Mac, she had been dating Alex for a year, meeting on a monthly basis to engage in sexual fantasies. For their latest tryst, Alex had planned a kidnapping scenario, revealing the team's theory that Liz's "abduction" was part of a sexual game was accurate. As revealed during his interrogation with Stella, Terry was still in love with his ex-wife, witnessing Liz and Alex's roleplay fantasy while following her. Enraged against Alex and wanting Liz to know he still loved her, Terry went into the house and blasted Liz for leaving him for Alex before stabbing Alex to death. Rather than being horrified by her ex-husband's actions, however, Liz turned heel after Terry cut her wrists free by kissing him, stating that she didn't know he was willing to kill for her. Afterwards, Liz sent Terry out before wiping off the knife, later making her claims of having been kidnapped by Alex and killed him in self-defense to cover for Terry. The episode ended with Terry being arrested after declaring killing Alex was worth knowing Liz loved him, with Liz presumably being arrested off-screen as a conspirator.