Compulsioncriminal Minds : Season 1 Episode 2 -

Clara traps three classmates in a science building elevator on the third floor, dousing them with chemicals and preparing to set them ablaze.

The team originally misinterprets a distorted tip-line message as "I do this for Karen," but later realizes she is saying "Charon"—the ferryman of the dead in Greek mythology. The Unsub: Clara Hayes

The second episode of Criminal Minds , titled "," follows the Behavioral Analysis Unit (BAU) as they hunt an unconventional serial arsonist on a college campus in Tempe, Arizona. Unlike typical arsonists who watch their fires for pleasure, this "unsub" (unknown subject) kills victims in private, suggesting a different psychological driver. The Arsonist's Profile CompulsionCriminal Minds : Season 1 Episode 2

Agent Hotchner confronts Clara, attempting to talk her down to buy time. When she refuses to stop, Hotchner shoots her in the leg, allowing the team to save the students. Criminal Minds Season 1 Episode 2: "Compulsion" summary

The unsub is obsessed with the number three, believing it has divine significance. Clara traps three classmates in a science building

The investigation leads to , a chemistry student who survived a traumatic house fire as a child. She believes she is testing her victims' purity through fire.

The team struggles because the perpetrator doesn't fit the standard profile of a male arsonist motivated by power or revenge. Dr. Spencer Reid eventually identifies the motive as —a form of Obsessive-Compulsive Disorder (OCD) involving religious or moral obsession. Unlike typical arsonists who watch their fires for

Fires are set in patterns of three (e.g., the first on March 3rd at 3:00 PM), and the unsub performs ritualistic actions in threes, such as turning doorknobs or repeating words.