Watch NCIS: Los Angeles – Season 4 Episode 20: Purity
Cast: Chris O'Donnell , Daniela Ruah , Eric Christian Olsen , Medalion Rahimi , Caleb Castille , Gerald McRaney , LL Cool J
Directors: Shane Brennan
Watch NCIS: Los Angeles – S4E20
Episode Overview
When cyanide in a communal water jug lethally poisons a lieutenant and leaves a Navy pilot in serious condition, the NCIS: LA team investigates whether this is an isolated incident or an early test for large-scale water contamination.
