Petrosian is seen in only two eps: "Rescue" in season 1, and "New Regime" in season 2. In the episode "Rescue" Petrosian is revealed to be a deep cover, level 9, operative of Section One for over 17 years as the head of the Russian Secret Police. When "brought in" in the same episode he shows a remarkable fascination with Nikita. He returns for an encore performance in "New Regime" in season 2 where he attempts to take over Section One and kill Operations. When the plan fails he is cancelled.