In the late 1920s the buildings of the Soviet secret services were located in the Katyn Forest. This was evidenced, among others, by the following inscription: „Special GPU (Soviet Political Police) zone. Authorized personnel only”. In 1931 a certain section of the forest was surrounded by barbed wire. A large villa housed a resort for NKVD officials from Smolensk. In the 1930s, NKVD functionaries began to bury the bodies of the victims of Stalinist crimes in this region, and precisely at the „Kozie Góry” (Goat Hills) site.
In the spring of 1940, this place was the site of executions of about 4.400 Polish prisoners of war from the Kozelsk camp, carried out by the NKVD. (Initially the POWs were killed in the forest, then in the basement of the villa). The bodies of the murdered were then buried in mass death pits. In 1943, the Germans publicized the case of the discovered graves of Polish officers. Three commissions: a German, an international and a technical one of the Polish Red Cross carried out the exhumations. Thanks to this work, it was possible to establish the names of the murdered people and retrieve dozens of documents that the criminals had left in the pockets of the victims. These included ID cards, letters from the relatives, photographs and personal documents. Furthermore, identification tags and uniforms with epaulets were also left with the bodies of the victims. In 1944, the Soviets carried out a similar exhumation, albeit on a smaller scale. Importantly, they aimed at disavowing the German findings from 1943 which made the NKVD responsible for the crime. Therefore, the Soviet special services planted a dozen or so forged documents and letters in the Katyn graves. That was supposed to change the interpretation of the case and shift the responsibility for the crime on to the Germans.
Polish specialists conducted research in Katyn once again in the years 1995-2000. They retrieved 1.018 valuable artifacts (made of wood, fabric, ceramics, metal, glass, rubber, cork and plastic) from the grave pits. All items excavated at that time are currently stored in the Katyn Museum in Warsaw.
The Katyn Cemetery was opened in July 2000. The Katyn Memorial is exposed to extremely aggressive attacks by the Russian propaganda connected with the popular idea of anti-Katyn. One exemplification of this was the 2017 exhibition broadly advertised in the Russian media. The exhibition informed about the number of deaths among Soviet soldiers, mainly the result of an epidemic, in Polish captivity after the war of 1920. (Polish sources estimate the number of deaths at about 16 thousand whereas the Russian ones at 82 thousand). The exhibition met with a strong protest from Poland.