Arkady Kolcheck is a friend of G. Callen and the liaison for Operation Cossack.
He is now a retired KGB officer who lives in Los Angeles.
He was thought to be the traitor who was responsible for Callen's teammates being killed during Operation Cossack in Russia.
He eventually left the KGB sometime afterwards and now runs a private security firm based in Los Angeles. He is also currently some kind of Confidential Informant to Callen and a source of information to NCIS.
- Vyto Ruginis previously appeared in the JAG Season 8 episode, Meltdown (episode) which also served as a backdoor pilot for the main NCIS series.