Answer: NKVD
The People's Commissariat for Internal Affairs (NKVD) was the interior ministry of the Soviet Union. This agency was part of the secret police force under Joseph Stalin. It was responsible for conducting police work and overseeing prisons and labor camps. After 1934, the Commissariat had a monopoly over law enforcement until the end of World War II. It was known for its role in political repression and it is usually associated with Stalin's purges.