The Vinnytsia massacre was the mass execution of between 9,000 and 11,000 people in the Ukrainian town of Vinnytsia by the Soviet secret police NKVD during the Great Purge in 1937–1938, which Nazi Germany discovered during its occupation of Ukraine in 1943. The investigation of the site first conducted by the international Katyn Commission coincided with the discovery of a similar mass murder site of Polish prisoners of war in Katyn. Nazi propaganda invoked mention of the massacre to illustrate communist terror by the Soviet Union.