<P> When Dexter is 18, Harry is diagnosed with cancer and hospitalized . There, Harry gives Dexter his "permission" to kill his first human victim, a nurse who is murdering her patients with overdoses of morphine . </P> <P> Throughout the novel, Dexter is involved in the investigation of the "Tamiami Butcher", a serial killer who dismembers his victims and puts the body parts in refrigerated trucks . The killer begins leaving taunting clues for Dexter to draw him in personally . The killer kidnaps Deborah and meets with Dexter in a storage container, and reveals their true connection: he is Brian, Dexter's biological brother . Brian tells Dexter that as children, they witnessed their mother's brutal murder at the hands of drug dealers, and were locked in a crate for two days, surrounded by dead bodies . Dexter persuades Brian to spare Deborah, and instead the two of them kill Lieutenant Migdia LaGuerta; a spiteful, manipulative woman skilled only in political gamesmanship and does not care about other people (this does not occur in the TV series, in which LaGuerta--whose first name is changed to "Maria"--is a recurring character until her death at the end of the seventh season). </P> <P> At the end of the novel, Deborah learns of Dexter's secret life after he saves her from Brian . She appears to accept it, but in subsequent books feels torn between her duties as a police officer and her loyalty to Dexter, whom she loves as her brother . </P> <P> Dexter's nemesis, Sergeant Doakes, suspects Dexter of being involved in LaGuerta's murder, and starts following him around . Doakes and Dexter are soon forced to work together to stop "Dr. Danco", a psychopathic surgeon who removes his victims' limbs and sensory organs, leaving them in a state of living death . </P>

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