NCIS: Season 7, Episode 5

7 - 5: Code of Conduct

On Halloween night the team investigates what looks to be the unfortunate suicide of Lance Corporal James Korby who is found dead in his car. However, they soon discover that Korby was murdered as his organs were frozen with liquid nitrogen and that when he attempted to breathe, the nitrogen entered his lungs, suffocating him. However it's also discovered that Korby has scar-tissue from a previous poisoning and Gibbs suspect that the entire squad, fed up of Korby's jokes attempted to kill him. Someone got Korby to drink the nitrogen and staged his death to look it like a suicide. Tony can