<P> Debra is characterized as smart and capable, yet unsure of herself, and so she relies upon Dexter's seemingly limitless expertise on murderers to solve difficult cases . Initially assigned to Vice, she is desperate to be transferred to Homicide . After Matthews promotes her, she starts to grow self - confident, relying less on Dexter's abilities and more on her own . </P> <P> Newly promoted to the homicide department, Debra's first case is a series of murders committed by "The Ice Truck Killer", who preys on prostitutes and leaves their dismembered bodies in refrigerated trucks . She works hard on the case, but her progress is hampered by her own insecurity and her antagonistic relationship with Lieutenant Maria LaGuerta (Lauren Vélez). </P> <P> She starts dating, and eventually falls in love with, Rudy Cooper (Christian Camargo); unbeknownst to her, he is actually the Ice Truck Killer, and is only dating her in order to get close to Dexter . At the end of the season, Rudy proposes to her and she accepts . Rudy--who is actually Brian Moser, Dexter's biological brother--then kidnaps her to reveal himself to Dexter . He binds her to a table in the same manner that Dexter kills his victims, while Dexter and Brian discuss her fate . Dexter ultimately saves her life, and reluctantly kills Brian to keep her safe . </P> <P> Debra is frail at the start of season two, still recovering from her ordeal with the Ice Truck Killer; she feels that she is not a good detective because she didn't spot that her fiancé was a serial killer . However, FBI agent Frank Lundy (Keith Carradine) reassures her otherwise and they, mid-season, develop a romantic relationship, which ends when he is called away from Miami . She stays in Dexter's house while she deals with the trauma . </P>

When does debra find out about dexter's brother