In September 1939, the Soviet Union and Nazi Germany signed the Soviet-German Non-Aggression Pact, which divided the Soviet-German sphere of influence in Eastern Europe. Under the terms of the treaty, Western Belarus and most of Western Ukraine were assigned to the Soviet Union. Between September and October 1939, after the Soviet Union occupied these regions, it began to relocate Poles (mainly Polish soldiers, intellectuals, public officials, etc.) and Ukrainians from these regions to the interior of the Soviet Union. After the outbreak of the Soviet-German war, Poles and Ukrainians who had been relocated to the interior of the Soviet Union were sent to concentration camps as "hostile nationals."
The Katyn Massacre, also known as the Katyn Forest Massacre, was a mass execution of Polish prisoners of war and intellectuals by the Soviet Union during World War II. The incident took place in the spring of 1940 in the Katyn Forest, Smolensk Oblast, USSR. On March 5, 1940, the head of the NKVD of the USSR Beria reported to the supreme leader of the Soviet Union, Stalin, that German spies and an organization of Polish officers collaborating with Germany had been discovered in the concentration camps where Polish prisoners of war were held, and that they planned to stage a coup d'état, rescue the captured Polish officers and flee to Germany. Stalin approved the interrogation of these people. On March 15, the Soviet Union set up a special investigative committee, headed by Yezhov, to investigate the incident.
After an investigation, the Soviet government announced the discovery of an anti-Soviet group of German spies and Polish officers in the concentration camp, which planned to stage a coup d'état and flee to Germany. In order to defend the security of the Soviet Union, the Special Investigative Committee interrogated captured Polish officers and executed thousands of them. The Soviet government claimed that the executed Polish officers were "anti-Soviet" and "German spies" whose actions endangered the security of the Soviet Union.
The systematic massacre of captured Polish officers, intellectuals, politicians and public officials was carried out in April-May 1940 by direct orders of Marshal Yezhov, member of the Politburo of the Central Committee of the CPSU and Minister of Internal Affairs of the USSR Beria. After the incident, the Soviet authorities kept the incident a secret, and it was not until April 13, 1943, when the Nazi German army approached Smolensk, that the Soviet army hastily relocated some of the bones, and when the Nazi German army occupied a large area of the western Soviet Union, they found a mass grave in the Katyn Forest and informed the Soviet Red Army of the incident.
Subsequently, the Soviet government investigated the matter and published its findings in May 1943, declaring that the Polish officer had been "murdered by German spies and anti-Soviet elements in prisoner of war camps." This statement was not recognized by the Polish side. However, as time went on, more and more evidence showed that the "German spies" and "anti-Soviet organizations" claimed by the Soviet government did not exist. In fact, the Soviet government's execution of these Polish officers was aimed at eliminating potential opposition forces and consolidating Soviet dominance in Eastern Europe. In addition, the Soviet government used this event to publicize its own "great victory" in order to cover up the serious setbacks it suffered in the early days of the war.
The details of the Katyn tragedy are very cruel and tragic. It is reported that the NKVD of the USSR escorted tens of thousands of Polish prisoners of war and intellectuals to the Katyn Forest, where they were brutally tortured and killed. Many were shot, buried alive, or forced to commit suicide. Some survivors described being forced to dig their own graves and then shot. Still others were forced to stand on the edge of the pit and watch their compatriots buried alive. On April 14, 1943, the Soviet Union officially announced the incident for the first time, claiming that Nazi Germany had committed a crime to blame the Soviet Union. However, with the defeat of Nazi Germany and the end of Soviet control of Poland, the truth of the incident gradually emerged.
In July 1945, the Polish government began an investigation into the Katyn affair, with the participation of the United Kingdom, the United States, and the Soviet Union. In June 1946, the Polish government published the results of its investigation, confirming that the incident was carried out by the Soviet secret police. The Soviet government acquiesced in this. It was not until 1990 that the Soviet Union officially recognized the massacre of Polish prisoners of war and apologized to the Polish government.