Dexter (episode)
Dexter is contacted by his foster sister Debra (Jennifer Carpenter), a vice officer in the Miami Metro Police Department. Dexter, a blood spatter analyst for the department, assists Debra in investigating an apparent serial killer targeting prostitutes. Dexter examines the latest victim and is shocked to find no trace of blood on the dismembered corpse. At the police station, Dexter discusses another murder case being handled by James Doakes (Erik King), a detective who dislikes him. Later, Dexter watches Jamie Jaworski, a murderer who escaped justice due to a faulty warrant, and breaks into his home to find evidence. Once he confirms that Jaworski is guilty, Dexter meets with his girlfriend Rita Bennett (Julie Benz), a former victim of domestic abuse victim; Rita has two young children, Astor and Cody. While on a date with Rita, Dexter finds another murder scene with no traces of blood, this time with the victim's head missing. Dexter theorizes that the killer murders his victims in extreme cold, explaining the absence of blood, and might be using a stolen refrigerated truck. Dexter allows Debra to pitch the theory, but their superior officer, Lt. María LaGuerta (Lauren Vélez), dismisses it.
Debra Morgan
After consulting with forensics technician Vince Masuka (C. S. Lee), however, Debra deduces that Trinity could not have been the shooter. During a Thanksgiving dinner with Dexter's family, Debra remembers a conversation she had with reporter Christine Hill (Courtney Ford), and realizes Hill has knowledge of the shooting that no one outside the police department knew about, and concludes that she was the shooter. This is proven true in a later episode revealing that Hill is Trinity's daughter. Hill confesses to Debra that she killed Lundy, moments before she commits suicide. Debra then renews her search for Harry's mistress, and finds out about Laura Moser, and the fact that Dexter and the Ice Truck Killer are brothers. She tells Dexter the news (which he already knew), and then tells him that he is "the one consistently good thing" in her life.