As early as September 19, the People's Commissar for Internal Affairs and First Rank Commissar of State Security, Lavrentiy Beria, ordered the NKVD to create the Administration for Affairs of Prisoners of War and Internees to manage Polish prisoners. The NKVD took custody of Polish prisoners from the Red Army, and proceeded to organise a network of reception centers and transit camps and arrange rail transport to prisoner-of-war camps in the western USSR. The camps were at Jukhnovo (Babynino rail station), Yuzhe (Talitsy), Kozelsk, Kozelshchyna, Oranki, Ostashkov (Stolbnyi Island on Seliger Lake near Ostashkov), Tyotkino rail station (56 mi/90 km from Putyvl), Starobielsk, Vologda (Zaenikevo rail station) and Gryazovets.
Kozelsk and Starobielsk were used mainly for military officers, while Ostashkov was used mainly for Boy Scouts, gendarmes, police officers and prison officers. Prisoners at these camps were not exclusively military officers or members of the other groups mentioned but also included Polish intelligentsia. The approximate distribution of men throughout the camps was as follows: Kozelsk, 5,000; Ostashkov, 6,570; and Starobelsk, 4,000. They totaled 15,570 men.
Once at the camps, from October 1939 to February 1940, the Poles were subjected to lengthy interrogations and constant political agitation by NKVD officers such as Vasily Zarubin. The Poles were encouraged to believe they would be released, but the interviews were in effect a selection process to determine who would live and who would die. According to NKVD reports, if the prisoners could not be induced to adopt a pro-Soviet attitude,They were declared "hardened and uncompromising enemies of Soviet authority."
According to data in the possession of the Polish government-in-exile, in early 1940 the Soviet Union held as many as 15,000 Polish prisoners of war, of whom 8,300 were officers. Taken prisoner by the Red Army in the second half of September 1939, they were interned in three camps: Kozelsk, Starobelsk, and Ostaszkow. Late that year, there were reports that the three camps had been disbanded. In 1941 and 1942, the Polish government-in-exile repeatedly asked the Soviet Union for information on the prisoners’ fate, but to no avail.