Josef Skála, former deputy leader of the Communist Party of Bohemia and Moravia, and two other men were convicted for comments over the 1940 killings in the Katyn forest in western Russia.

The defendants received an eight-month suspended sentence for disputing during an online debate in 2020 that the massacre was carried out by the Soviets.

The court ruled that unequivocally proven historical truth cannot be questioned or debated.

During the online debate, Skála referred to the exhumation of thousands of bodies from mass graves as “alleged.”

The defendants invoked freedom of speech in their complaint to the court, but the judges said such freedom is not absolute.

“The plaintiffs, completely in the spirit of communist propaganda doctrine, subordinated the truth to ideological goals,” said the court.

As a result, the judges added, the men endorsed a view similar to the one that “the Earth is flat.”

In 1940, the NKVD – the Soviet secret police – executed over 22,000 Polish prisoners of war. These were mostly army officers, policemen and intellectuals who had been captured by the Soviet Union after its invasion of Poland in 1939. The massacre was named after the Katyn forest in western Russia, where some of the mass graves were first discovered by German Nazi forces.

The Soviet Union initially blamed the massacre on the Nazis, and generations of Russian propagandists repeated this version until 1990, when the country’s government officially admitted that the NKVD had been responsible for the killings.