Aubrey Haskins (Audrey Marie Anderson) is the main villainess of "I, Witness," episode 7.13 of Castle (airdate February 2, 2015). She was the general counsel of Whitfield and Galloway, a stockbroker company that was started up by Cole Whitfield.
Aubrey's brief backstory revealed that she was a sorority sister of Cole's first wife Mallory, who died by falling into a ravine in Angeles National Forest. Aubrey always believed and even told her friends that Cole got away with murder due to the suspicious circumstances of Mallory's alleged hiking accident, especially since he was the only witness to the event and had inherited several million dollars as a result. In the years that passed, Aubrey plotted revenge on Cole, and she joined his company as part of her scheme. After hearing his second wife Eva vent about their marriage and his adultery, Aubrey contacted her and (along with Robert James—the husband of one of Cole's two mistresses) cooked up a plan to ruin Cole's life.
The plan in question began with making it appear that Cole killed Eva at their house, which would send the former to jail and leave his fortune to be inherited by the latter while she started a new life in Switzerland. Initially, their machinations were successful, as the "murder" (which was "committed" by Robert) was witnessed by Richard Castle, a high school classmate of Eva's whom she had hired to supposedly find evidence of her husband's infidelity, leading to Cole becoming the prime suspect in his second wife's "death", similar to what happened after Mallory perished. Aubrey's appearances in the episode had her supposedly coming to the defense of Cole's other mistress, Taylor McKinley, as well as Cole himself at one point.
However, Eva had second thoughts about helping her husband get convicted and planned on coming forward about everything, which led to the vengeful mastermind killing her with an unknown blunt instrument in Eva's temporary studio apartment to keep her quiet. After tossing her former female accomplice's corpse into the Hudson River, the evil Aubrey killed Cole at the Whitfield residence by drugging him with high levels of sedatives in his alcohol and then hanging him from a balcony inside the house to make it look like a suicide. Her villainy was revealed when Castle and Kate Beckett confronted her with their knowledge of Eva's blood and DNA being found in the trunk of her car, along with detailing exactly what she had done, though Aubrey remained smug. After that, she was handcuffed and arrested for her crimes. A disappointed Beckett mused how Aubrey wanted justice for one murder, only to end up committing two herself.