Chronology of Soviet secret police agencies to operate as well. Chronology of Soviet secret police agencies <br> There was a succession of Soviet secret police agencies over time. The first secret police after the October Revolution, created by Vladimir Lenin's decree on December 20, 1917, was called "Cheka" (ЧК). Officers were referred to as "chekists", a name that is still informally applied to people under the Federal Security Service of Russia, the KGB's successor in Russia after the dissolution of the Soviet Union. For most agencies listed here secret policing operations were only part of their function; for instance, the KGB was both the secret police
NKVD political prisoners in 1939–1941, including the Katyń massacre. NKVD units were also used to repress the prolonged partisan war in Ukraine and the Baltics, which lasted until the early 1950s. After the death of Stalin in 1953, the new Soviet leader Nikita Khrushchev halted the NKVD purges. From the 1950s to the 1980s, thousands of victims were legally "rehabilitated" (i.e., acquitted and had their rights restored). Many of the victims and their relatives refused to apply for rehabilitation out of fear or lack of documents. The rehabilitation was not complete: in most cases the formulation was "due to lack of