Doubt S3 E1

At an all-girls school in Flagstaff, Arizona, three women were already murdered when the BAU arrived. All the victims arms were crossed, which is a sign of remorse, and that the murderer wants the victim to rest in peace. The night the BAU arrives on campus, another girl is murdered. Her corpse shows no signs of fighting back, yet she was holding a mace. This indicates that the victim knew and trusted her killer, and that he is most likely part of the campus. The director of the college wants to evacuate the school for the protection of the students, and the BAU fears that this will only encourage the killer’s murdering spree. They are increasing the amount of security and surveillance in order to lower the chances of another murder. 

Profile: The un-sub is someone with high access to the college and community. He was able to kill and be unseen even in a highly trafficked and survived campus. He is a "spree-killer" because he has killed 4 women in three days (something has most likely set him off in the past few days). He has only killed white brunette women, so the stressor most likely involves a women in his life who fits the same description. (Wife, mother, girlfriend) The un-sub may feel emasculate, and rejection may be a common theme in his life. The un-sub displays a great amount of anger, and stabs his victims repeatedly, even after they're dead: seconds later he feels remorse. It is possible that he feels guilty because the victims trusted him.

 The BAU soon finds out that the un-sub is a member of the campus security, because markings on the dead women came from a Taser (the campus police are not allowed guns). Garcia, the computer analyst for the BAU, looks for any security guards who attempted to join the military, but failed. One campus officer Nathan Tubbs did, and was declined because he failed his psych evaluation. He was one of the only officers to show up to all the crime scenes, even when he was not on duty. Nathan Tubbs also recently lost custody of his daughter after a divorce with his wife. The police break into his apartment and find newspaper clippings of all the killings and knifes. Nathan isn’t on the schedule to work, yet is patrolling around and finds a student walking alone. He offers to drive her to her car because "it is his duty to keep her safe". The BAU solve that he is the killer, and find him and the girl in the car before he could harm her.

The police psych evaluation says he had border line, antisocial, and sociopathic tendencies. While in custody, another murder occurs, by someone posing to be the serial killer. It turns out to be a girl on campus, Anna, who died her hair brown for Nathan Tubbs. Once he was released (because they had no evidence), Anna takes Tubbs to a courtyard where they can be alone. The girl is a recluse, antisocial, and often talks about suicide. Anna says she wants Nathan to kill her like the other girls because she is too afraid to commit suicide herself. Nathan refuses so she stabs him in the stomach, then stabs herself. Both end up dying, and while the result was devastating, the BAU knew that Nathan Tubbs would no longer be able to harm any more girls.