S4, E13: While searching for a missing middle school teacher, the team begins to suspect that she may be having an inappropriate relationship with a 14-year-old student who is also nowhere to be found. Claire Hunter goes missing after losing her temper and punching a man in the face at the gym after he flirted with her disinterested colleague, Angela. The team members initially wonder if the bloodied and humiliated man may be involved in Claire's disappearance, and they also question what motivated the never-married Claire to legally change her surname prior to moving to her current town and job. Additional theories abound onceher ex-boyfriend reveals that he recently showed up at her apartment and, despite Claire's insistence that it wasn't how it looked, saw that her young student had just showered there.