Stella Kaine, aka Reaper32 (Kelly Osbourne), is the main villainess from "The Walking Dead," episode 2.13 of CSI: Cyber (airdate February 14, 2013).
Stella originally appeared as a woman in distress, as she was saved by Andrew Michaels (Avery Ryan's ex-husband) from being attacked by a mugger. As it turned out, however, Stella was a sinister hacker and a "digital killer," and the attack was used as a ploy to hack into Andrew's laptop and "kill" him. Avery received the news about Andrew's "death," only to see him alive and well, leading to the realization that he was hacked and digitally killed.
Stella was found at a nightclub and arrested by Elijah Mundo and Daniel Krumitz. After making a deal for immunity, Stella helped the squad track down her partner in her online crimes, who was known as Reaper32, and described by Stella as someone who goes after anyone and everyone, with Stella claiming that she draws the line at children and law enforcement. After Stella left the headquarters as part of her deal, her information led to Mundo taking down and handcuffing a man believed to be Reaper, but Daniel realized that Stella was lying all along and she was Reaper.
The man who Mundo handcuffed was the "mugger" aligned with Stella during her hack on Andrew, a hack that a man named Daniel Booker (the ex-husband of Andrew's fiancée) paid her to do. It was revealed that Stella was the one who digitally killed a pair of witnesses testifying against Rafael Pintero, which allowed Pintero to easily kill them himself. The villainous hacker was on her way out of the country when Avery and Daniel appeared, with the latter handcuffing Stella. During the arrest, the evil Stella arrogantly boasted that she would only get two years and be out for good behavior, only for Avery to inform her that her hack resulted in two murders, and she would be facing 25 years to life.