Jamie Silberhartz

The BAU team investigates a mass murder at an Internet security company in Charlottesville, Va., but clues reveal it is not a typical serial killer at work. Also, Prentiss must complete recertification training under Morgan's watchful eye.

Melinda helps the ghost of a little girl who has been missing for 12 years and blames her brother.

Cooper must decide whether or not to punish Mason after he is caught stealing; Pete and Violet struggle to split time with Lucas; Addison prepares for a new baby.

When a young woman, Katie Duncan (ALEKSA PALLADINO), goes missing after a priest performs an exorcism on her, her brother asks Martin for help. Katie had spoken fondly of Martin because she interned at the FBI when Martin was still working on white-collar crimes. Martin and the team soon discover that the priest, who also vanished, was suspected of murder a year ago when a man died during his exorcism. They also learn that Katie scheduled the exorcism because her mental illness, which she had managed with medications for many years, began making her feel like she was possessed by something "dark." Meanwhile, Jack and Anne (recurring guest star MARY ELIZABETH MASTRANTONIO) forge ahead with their plans to buy an apartment together as they prepare for their baby's birth. DEE WALLACE ("E.T. the Extra-Terrestrial") guest stars as Lara Duncan, Katie's mother.

The team searches for a teenage girl who disappeared after trying to dodge the advances of an aggressive boy. After the guy sent her a shockingly lewd note, she was last seen leaving an Internet café with him following her. Meanwhile, Samantha's estranged sister, Emily Reynolds (recurring guest star MOLLY PRICE - "Third Watch"), attempts to reconnect with her.