In 1943, Nazi Germany announced the discovery of a mass grave site in the Katyn Forest. They announced that they discovered a ditch “28 meters long and 16 meters wide, in which the bodies of 3,000 Polish officers were piled up in 12 layers.” The Polish government, who were at the time exiled and residing in London, asked the International Red Cross to do an investigation. The Soviet Union denied involvement up until 1990, when Gorbachev admitted that the executions were ordered by Stalin and carried out by the NKVD, the Russian secret police, on March 5, 1940. The number of victims were tallied at 22,000 Polish officers.
The massacre, executed in 1940, was the result of the partitioning of Poland between Nazi Germany and the Soviet Union in September 1939. The Soviet Union claimed that it was liberating the Ukrainians and Belorussians from their oppressive Polish rulers. The Soviet Union arrested Polish landlords, officials, intellectuals, and officers, who were then sent to prison camps. The number of arrests ranged in the tens of thousands. Lavrentii Beria, head of the NKVD, considered it inconvenient to feed and safeguard such a high number of prisoners, and thus ordered the executions of some 22,000 of them.
In the memo that proposed the executions, it was stated that these imprisoned Polish officers were members of the Polish counter-revolutionary resistance groups, and that they possessed a hatred for the Soviet system. It also claimed that these Polish officers were carrying out counter-revolutionary acts in the prison camps. It was recommended that they were to be executed at gunpoint. In 1941 when the Polish general Wladyslaw Anders was organizing his army and requested information regarding the missing Polish officers, Stalin reassured them that all the Poles were freed, but not all could be accounted for because they “lost track” of them in Manchuria.
One historian, Gerhard Weinberg, believed that Stalin signed the executions because he wanted to make Poland weaker, since many of the officers also comprised Poland’s technical and intellectual elite. Stalin foresaw a potential future where a hostile Poland would border eastern Russia. Stalin endeavored to weaken Poland to discourage any hostilities.
In 1990 when it was reveal that the massacre was indeed carried out by the Soviet Union, it was also revealed that Katyn was only one of the sites where the Polish officers were buried. The other burial sites are Piatichatki, Bykivnia, and Mednoye. The Polish officers were massacred not only in Katyn, but in Kharkov, Kherson, Kiev, Minsk, and Tver.
Pic 1: http://soviethistory.macalester.edu/index.php?page=subject&show=images&SubjectID=1943katyn&Year=1943&navi=byYear