Eva Whitfield

Eva Whitfield (Brianna Brown) was the hidden (redeemed) secondary villainess of "I, Witness," episode 7.13 of Castle (airdate February 2, 2015). Born Eva Hendricks, she attended Faircroft Preparatory Academy alongside Richard Castle, where they had AP Chemistry together. Her introductory appearance had her reminding Richard of how she used to cheat off of his work.

Eva hired Richard in proving that her stockbroker husband Cole was cheating on her to see if "there's anything left in [their] marriage to fight for." Unbeknownst to Richard, she vented to the episode's true main antagonist about the deteriorating marriage while consulting with them, especially regarding a prenuptial agreement Cole insisted on—after which they convinced her to punish him.

The heel-turned Eva approached Robert James (a Whitfield and Galloway executive whose wife was one of Cole's two mistresses) and enlisted him to be part of the vengeful scheme against her husband. It also involved manipulating Richard into investigating Cole, with the former finding out about the latter's affair with Taylor McKinley (his other mistress). Richard's phone conversation with Eva regarding his infidelity saw her crying and mentioning she was packing up to leave him—along with asking him to stop by the Whitfield residence so she could receive pictures proving "her marriage [was] over."

It was at 7:45 PM when Robert "murdered" Eva as she "screamed" twice, dragged her "corpse" to his car, and drove away. The supposed "attack" was witnessed by Richard, who followed them into a nearby forest that they lured him to. After Robert punched him in his face (thus knocking him unconscious), the pair returned to the "scene of the crime" to clean up all implicating evidence. He then gave his co-conspirator a key to a corporate apartment before driving back to his house, and Eva left for the apartment once she left a note for Cole telling part of the truth. Later that night, Eva transferred the $7.4 million in her joint bank accounts with her husband into a bank account in Switzerland—where she was to fly to and reside.

Eva called Cole from next to Taylor's apartment building at 9:35 AM the next morning and told him to go screw himself while disclosing what she had done with the accounts' money. However, her redemption began when she felt regretful and stressed out about enacting a plan that wasn't her idea in the first place. She also had second thoughts about watching Cole get convicted, prompting her to call Robert and tell him everything about her apprehension.

Eva's redemption was cemented as she called her other co-conspirator from the apartment's landline—informing them she didn't want to go through with framing Cole and was going to come forward. With years of plotting their own revenge against Cole about to be ruined, the real mastermind behind Eva and Robert's plan confronted her there. In the ensuing struggle, they used an unknown blunt instrument to fatally bludgeon Eva before tossing her corpse into the Hudson River.

Her posthumous villainous reveal occurred when Richard figured out Cole was truthful about his second wife being alive (prior to Eva's actual death), and further revelations concerning the plan led to the mastermind's climactic reveal as well as their arrest.