The title was interesting as it reflects Polish government's later international legal effort to categorise Katyn as genocide which has no time limits for bringing to trial perpetrators for possible conviction. I think this was rejected by European Court of Human Rights and it is now classified as a war crime rather than genocide?
update------found the text of the 2012 judgement online.
"The court said on Monday, Apr. 16, it had concluded that the executions of Polish prisoners of war were a war crime, as the humane treatment of POWs and the ban on murders were a part of the conventional international law the Soviet authorities were compelled to observe."
"Although war crimes have no statute of limitations, no new evidence was found in the period since the ratification of the Human Rights Convention to compel the Russian authorities to reopen the case, the court said."