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
Polish Operation of the NKVD of the Polish diversionist and espionage groups and POW units"," was approved on August 9, 1937 by the Party's Central Committee Politburo, and was signed by Nikolai Yezhov on August 11, 1937. It was distributed to the local subdivisions of the NKVD simultaneously with Yezhov's thirty-page "secret letter," explaining what the "Polish operation" was all about. The letter from Yezhov was titled, ""On fascist-resurrectionist, spying, diversional, defeationist, and terrorist activity of Polish intelligence in the USSR"". Stalin demanded the NKVD to "keep on digging out and cleaning out this Polish filth." The "Order" adopted the simplified so-called "album procedure" (as