Another falsification ( confirmed the Russian State Duma ) concerned the 24 January 1944 communiqué about the Katyn massacre ( 1940 ) , published under the title " The Truth about Katyn " . This lengthy document purported that the mass shootings of the Polish prisoners had been done by the Germans . In fact , the crime was committed by the Soviets on Joseph Stalin 's orders . The truth was first revealed by the international Katyn Commission but confirmed by Soviet documents only after they had been declassified and made public by the Government of the Soviet Union in 1990 during the last days of the USSR . They proved conclusively that 21,857 Polish internees and prisoners of war were executed by the Soviet Union after 3 April 1940 including 14,552 prisoners from three largest Soviet POW camps at this time . Of the total number of victims , 4,421 officers were shot one by one at the Kozelsk Optina Monastery , 3,820 at the Starobelsk POW camp , and 6,311 at the Ostashkov facility , in addition to 7,305 Poles secretly eliminated in the Byelorussian and Ukrainian SSRs ' political prisons . The head of the NKVD department , Maj. General P. K. Soprunenko , organized " selections " of Polish officers to be massacred at Katyn and elsewhere
Katyn massacre
Katyn massacre
Extraordinary State Commission