Human rights groups and historians believe up to 21,000 people were murdered in what became known as the Katyn Forest Massacre.
A Russian government investigation into the case has been ongoing since the early 1990s. However, the government closed the investigation on 11 March.
Boris Belenkin is a historian who works for Russia’s prominent human rights group Memorial. He says his organization today sent a letter to the Russian authorities asking for the Katyn investigation to be reopened:
“The reason behind this letter was the general military prosecutor’s announcement about the closure of the Katyn case and his claim that the death of 1,800 people had been confirmed with absolute certainty, when we know that at least 14,000 have died," Belenkin says.
Belenkin says the government has failed to provide any other official information as to why the investigation has been closed.
Russia has been reluctant to acknowledge that the killings constituted a war crime. It wasn't until 1990 that Soviet leader Mikhail Gorbachev admitted his country’s involvement in the massacre.
As a reconciliatory gesture, in 1992 the Russian government handed over to then-Polish President Lech Walesa previously secret documents testifying that Josef Stalin had ordered the killing.
Russia’s recent decision to close the investigation, however, could face criticism ahead of the grand ceremonies planned for 9 May to mark the 60th anniversary of the end of the Second World War.
Estonia and Lithuania have also dealt a blow to Russia by turning down its invitation to attend the May celebrations in Moscow, after saying their countries were oppressed by the Soviet regime. Latvian President Vaira Vike-Freiberga has accepted an invitation to attend the celebrations.
The Katyn issue could further erode relations between Russia and Poland. Polish lawmakers last month renewed calls for Russia to classify the massacre as genocide and bring the remaining perpetrators to justice.
Belenkin views Russia’s decision to close the investigation as a sign of the growing patriotic and nationalist trend under the government of President Vladimir Putin.
But Sergei Markov, director of the Institute for Political Studies in Moscow, says Moscow is mainly trying to protect its image:
“Moscow is trying to minimize the damage done to its image by talk about the Katyn case. Katyn is one of the tragedies of the Second World War -- a tragedy that was not admitted for a long time by the Soviet Union, which did not want to hurt relations with its ally, socialist Poland,” Markov says.
Markov also speculates that Russia could be trying to avoid a potential series of damaging and costly lawsuits from descendents of victims if it fully admits to all the killings that took place:
“One can isolate several concrete episodes in the Second World War, and if Russia admits its responsibility in every one of these cases it might be sued for all of them," says Markov. "There would be a lot of economic consequences. I think Russia doesn’t want to create the possibility of such lawsuits taking place.”
Russian-Polish relations have been particularly strained over the past months, with Poland announcing in March that it planned to name a square in Warsaw after the slain Chechen separatist leader Dzhokhar Dudayev.
Moscow responded by threatening to rename the street in which the Polish Embassy has its seat in Moscow after Mikhail Muravyov, a Russian army general nicknamed the “hangman” for his ruthless suppression of the Polish uprising of 1863.