Contrary to the historical consensus and as acknowledged by both the Soviet Union (in 1991) and the Russian Federation (in 2004), Furr denies Soviet complicity in the Katyn massacre, arguing in a 2013 article in the "Socialism and Democracy" academic journal that the Katyn massacre was committed by the Nazi "Schutzstaffel" rather than by the Soviet NKVD. In 2010, Furr stated to have believed the widely-accepted view until the discoveries in the mass graves at Volodymyr-Volynskyi, which he claims prove his thesis. According to Furr, some Poles were likely killed by the Soviets in retaliation for their treatment of Russian prisoners of war and other civilians, which is part of controversies of the Polish–Soviet War, while Nazis shot the others later.