NCIS

Season 3, Episode 20

Episode Title: Untouchable

Air Date: 2006-04-18

Overview:

When a Pentagon cryptographer is found dead, the NCIS team has to discover whether the person was or wasn't a Pentagon mole, and if the person committed suicide. As the investigation continues, the team discovers that the person wasn't alone when she died, so someone must have murdered her. So, the team has to find the person, a mole, who murdered the cryptographer.