Some times I have seen communist leaning people attributing the Katyn massacre to the Nazis and claim that any connection to the Soviets was fabricated propaganda.
Consequently anyone citing it to show the Soviet Union wasnt all sunshine is labelled a Nazi apologist by them.
1) Is there any merit at all to those claims ?
2) Did the Nazis, even if they werent the perpetrators, use it as propaganda initially ?
Although only focused specifically on Katyn for a small portion, this will likely be of interest for you.