NCIS: Season 5, Episode 13

5 - 13: Dog Tags

When the NCIS team investigates a fatal dog mauling of a suspected drug smuggler within the K-9, Abby risks her career in hopes of proving the victim dog's innocence to save him from being put down. The team struggles with the case, with the director threatening to end their case, when they find a new victim and finally manage to track down the drug trafficker. The trafficker was one of the K-9 trainers, who secretly replaced her drug sniffing dog with an attack dog in order to smuggle drugs. Meanwhile, Abby befriends the "killer" dog, names him "Jethro", and works to keep him from being put down as she attempts to prove the dog is not guilty. However, her landlord doesn't allow pets, so she instead forces McGee to adopt him which he grudgingly agrees to do despite the fact that the dog attacked him at the beginning of the episode.