Kelly McCracken

Marissa and Ryan begin dating. Summer tries to deny her feelings for Seth as he gets closer with Anna. Kirsten and Sandy continue to clash. Julie reveals a new relationship.

The BAU travels to Dallas to assist in the search for a murderer who scares his victims with "missing" flyers that display the soon-to-be victims' photos.

J.D.'s ne'er-do-well brother (Tom Cavanagh) hits it off with Elliot.

When Dr. Alicia Seberg, a government research scientist (guest star Amy Price-Francis), is exposed to a deadly toxin while at work and has only hours to live, she calls Patrick Jane and the CBI to find her murderer.

A young mother's life is threatened by her ex-husband as their relationship turns deadly. With the determination of one officer and the help of unlikely informants, they uncover a relentless murder plot only an undercover operation can stop.