CBS

Season 5: Episode 4 - Reznikov, N.

Reznikov, N. : Callen follows the team to a crime scene where Callen’s father has apparently been kidnapped. Upon searching the house, the team finds a lifetime of surveillance photos of Callen. When facial recognition reveals the kidnapper is Vasile Comescu, Callen takes matters into his own hands. Callen takes down Vasile, but his "father” is shot and killed. Arkady reveals that the man was not his father but was watching Callen at his father’s request.