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The Cheka, short for the All-Russian Extraordinary Commission, and its successor, the OGPU, United State Political Administration, were two Soviet secret police organizations led by Felix Dzerzhinsky. The Cheka, established in 1917, was responsible for combating counter-revolutionary activities and became notorious for its brutal methods. It was replaced by the OGPU in 1922, which operated until 1934 when it was merged into the NKVD, another secret police agency.