This decision nullifies the frustrated efforts of relatives of the Katyn victims to have Russian authorities clarify the crimes against humanity perpetrated by Soviet special forces. After the signing of the Molotov-Ribbentrop Pact of August 1939 by the USSR and Nazi Germany, the Soviet Union occupied eastern Poland and arrested local the intelligentsia, government officials and the military. Thereafter the Communist Party bureau decided to kill over 20,000 of the prisoners.
Thousands of Polish and police officials were shot twenty kilometers from Smolensk in the forest of Katyn. In addition many more were killed in the cellars of the NKVD (precursor of the KGB) throughout Ukraine and Belarus.
After the retreat of Soviet forces from Poland the massacre at Katyn became a propagandistic issue. Nazi Germany's military had uncovered the Katyn mass graves and identified the NKVD as perpetrators. Moscow however blamed Nazi Germany. At the end of WWII, the "official version" was the USSR's. Poland knew the truth, but any public reference to it was forbidden by the communists in power.
The Soviet Union accepted blame on April 13, 1990, when Mihhail Gorbachov said that Joseph Stalin with the leading members of the communist party and government had given the NKVD the go-ahead to commit the atrocity. However it was not declared to be a crime against humanity in that only certain individuals of the time were directly culpable.
Russian military prosecutors had investigated the killings but ended the process in 2004 because the Katyn massacre had not been recognized as a crime against humanity or a war crime.
Earlier the Russian court did not satisfy the petitions of relatives applying for rehabilitation of the victims, explaining that the crime had expired and that such applications can be presented only by those whose human rights had been violated.