Europe's human rights court criticises Russia over Katyn massacre Soviet secret police murdered 22,000 Poles in Katyn, Russia, in 1940 Russia admitted in 1990 that it did commit atrocity but made no arrests Victims' families wanted ECHR to force Russia to publish 1990 probe But ECHR says it can't force Russia because it didn't exist in 1940 The European Court of Human Rights has criticised Russia for its investigation into the massacre of Polish war prisoners by Soviet troops but admitted it is powerless to do anything about it. Through April and May 1940, an estimated 22,000 Polish military officers and intellectuals were killed in Katyn, western Russia, many of them trucked in from prison camps, shot in the head from behind, and shoved into mass graves. After blaming Nazi Germany for the Katyn massacre for decades, the Soviet Union admitted in April 1990 that its forces were responsible. But none of the culprits has ever been identified and investigations have been shelved. But the ECHR today ruled it cannot judge whether Russia's 'secretive' investigation into the Katyn Massacre was adequate because it didn't exist when the atrocity was carried out. Horror: An estimated 22,000 Polish military officers and intellectuals were killed Katyn, western Russia, many of them trucked in from prison camps, shot in the head from behind, and shoved into mass graves It did, however, rule that Russia failed to comply with a human rights obligation to provide evidence by refusing to submit documents from the investigation and offered no substantive reason for keeping them secret. Relatives of those murdered by the Soviet secret police during World War II claimed that the 1990-2004 investigation by Russian authorities into the massacre was 'inadequate'. But the court said it lacked jurisdiction to judge on the matter because the Katyn massacre took place before the adoption of the European Convention on Human Rights in 1950. 'I can only say that we are rather disappointed by this verdict,' Deputy Foreign Minister Artur Nowak-Far said in a statement. Anger: After blaming Nazi Germany for the Katyn massacre for decades, the Soviet Union admitted in April 1990 that its forces were responsible. But none of the culprits has ever been identified (left is a memorial to the massacre in Kensington, London, and right is the one in Warsaw, Poland 'The ruling does not take into account all the arguments of the Polish side that have here a great moral and historic right,' he added. The Katyn killings have cast a shadow over relations between Poland and Russia for many years, with Warsaw especially disappointed that Moscow was not willing to transfer documents concerning the massacre for further analysis. Poland has repeatedly hit out at Moscow for not transferring documents concerning the massacre for further analysis (left: a document concerning the killings that bares Stalin's signature. Right: a film was made of the atrocity in 2007) Atrocity: A Polish soldier is pushed into a mass grave in a scene from teh 2007 film Katyn. On April 13, 1943, the Germans said they had found the mass graves of Polish officers in Katyn forest near Smolensk Germany invaded Poland from the west in 1939 and Soviet forces occupied the eastern half of Poland. As a result, tens of thousands of Polish military personnel fell into Soviet hands and were interned in prison camps inside the Soviet Union. On April 13, 1943, the Germans said they had found the mass graves of Polish officers in Katyn forest near Smolensk.