Trama

Detectives Benson and Lake get the help of an FBI agent as they search for a serial killer who brutally attacks young women. However, there are signs that the agent may not be able to handle the mental and emotional weight of the case.

An FBI agent with the Behavioral Analysis Unit joins Det. Benson in trying to track down a serial killer known as "The Woodsman". The Parks Department receives an e-mail telling of a dead dog in Central Park. The two volunteers who show up to dispose of the dog find someting else: the dead bodies of Kate Barrow and a "John Doe". She was killed by a serial killer known as "The Woodsman" who's into torture--hanging, burning, maiming, raping and dry drowning. He was killed by a bullet to the head. Olivia Benson is on the case without Stabler, but has a partner in Lauren Cooper, an immature but determined FBI agent who's haunted by the memory of the suicide of her mentor, Dr. Carl Tillman, who shot himself. We learn that Kate was victim number 22 for "The Woodsman" and that he likes to kidnap two girls at once, so one victim can listen to another being tortured. A CSI DNA match of the "John Doe" reveals that he is really Larry Moore--"The Woodsman". Moore was a park ranger who worked in the same states where the 21 victims were found. Olivia and Lauren's search of Moore's apartment results in the discovery of a key, which it is assumed belongs to the torture chamber Moore used to kill his victims. The detectives' search for the second victim leads them to a warehouse owned by a cruise line where they find the torture chamber and a hidden drawer containing Amy Dogue, bound with duct tape over her mouth, but still alive. The e-mail is traced to an internet cafe, and nearby security cameras catch Lauren leaving the cafe just after the e-mail was sent. Olivia tries to interrogate Lauren but gets nothing from her. Detectives searching Lauren's apartment come across the shell casing she took from the scene of the shooting. Casey, the D.A., has a hard time getting her to court for second degree murder--she did, after all, kill a man, but a man who murdered 22 women. The tally rises to 23 when Amy dies in the hospital from a mixture of cuts, contusions, electrical burns and septic shock. Widening her investigation, Olivia visits the widow of Dr. Tillman, who tells Olivia that she gave the gun her husband used to shoot himself to Lauren. A ballistic match shows that Dr. Tillman and Larry Moore were killed by the same gun. Olivia goes to Lauren's apartment to arrest her, and Lauren tells her that "Those who fight monsters should make damn sure they don't become one." These turn out to be Lauren's final words--she shoots herself.