One of the earliest–and certainly the most infamous–mass shootings of prisoners of war during World War II did not occur in the heat of battle but was a cold-blooded act of political murder. The victims were Polish officers, soldiers, and civilians captured by the Red Army after it invaded eastern Poland in September 1939. Strictly speaking, even the Polish servicemen were not POWs. The USSR had not declared war, and the Polish commander in chief had ordered his troops not to engage Soviet forces. But there was little the Poles could do. On 28 September, the USSR and Nazi Germany, allied since August, partitioned and then dissolved the Polish state. They then began implementing parallel policies of suppressing all resistance and destroying the Polish elite in their respective areas. The NKVD and the Gestapo coordinated their actions on many issues, including prisoner exchanges. At Brest Litovsk, Soviet and German commanders held a joint victory parade before German forces withdrew westward behind a new demarcation line.
Official records, opened in 1990 when glasnost was still in vogue, show that Stalin had every intention of treating the Poles as political prisoners. Just two days after the invasion began on 17 September, the NKVD created a Directorate of Prisoners of War. It took custody of Polish prisoners from the Army and began organizing a network of reception centers and transfer camps and arranging rail transport to the western USSR. Once there, the Poles were placed in “special” (concentration) camps, where, from October to February, they were subjected to lengthy interrogations and constant political agitation. The camps were at Kozelsk, Starobelsk, and Ostashkov, all three located on the grounds of former Orthodox monasteries converted into prisons. The NKVD dispatched one of its rising stars, Maj. Vassili Zarubin, to Kozelsk, where most of the officers were kept, to conduct interviews. Zarubin presented himself to the Poles as a charming, sympathetic, and cultured Soviet official, which led many prisoners into sharing confidences that would cost them their lives.