The Katyn massacre, carried out by the Soviet NKVD in 1940, was only one of many unspeakable crimes committed by Stalin's ruthless executioners over three decades. The mass murder of thousands of Polish officers was part of a relentless purge, … Cédric Tourbe, Dmitry Tokarev, Leon Trotsky, Lavrentiy Beria, Felix Dzerzhinsky, Vyacheslav Menzhinsky, Genrikh Yagoda Added on Amazon Prime 2020-12-21.