<P> After this trauma, Greenaway went on a four - month leave of absence in an attempt to heal and move on with her life . </P> <P> Despite having physically recovered from her injuries, she remained psychologically traumatized, as seen in the post-shooting changes in her personality--once open to others and full of laughter, Greenaway became distant, withdrawn, and hypervigilant . </P> <P> When she returned, a case involving a serial rapist affected her deeply, to the point that she panicked during an undercover operation, an action that prevented the team from obtaining probable cause to hold the assailant in custody . Upon seeing the suspect leaving the station Greenaway accused Unit Chief Aaron Hotchner of getting her shot . While her colleagues slept, Greenaway stalked the suspect . After over reacting to a comment she shot and murdered the alleged rapist in cold blood as he was walking away . Lying and claiming that he had drawn a gun on her first, Greenaway with the help of the local agent was ruled by local authorities to have acted in self - defense, although her BAU colleagues clearly thought otherwise . </P> <P> Reid, in particular, blamed himself for not having seen the signs of her impending breakdown and prevented the shooting, because on a previous night, he had dropped by her room to check on her and saw that she was drinking . </P>

Why did the character elle leave criminal minds