Their bodies were discovered in a series of large mass graves in the forest near Smolensk in Russia following Operation Barbarossa.

[1] An international commission of experts in anatomy and forensic pathology were brought in from 11 countries in Europe, predominantly from Nazi Germany's allied or occupied states.

Consequently, the German government made extensive reference to the massacre in its own propaganda in an attempt to drive a political wedge between the Allies of World War II.

[8][9] Of the total number of victims, 4,421 officers were executed by shooting at the Kozelsk Optina Monastery, 3,820 at the Starobelsk POW camp, and 6,311 at the Ostashkov facility, in addition to 7,305 Poles who were secretly executed in Byelorussian SSR and Ukrainian SSR prisons.

[9] Among the victims were 14 Polish generals including Leon Billewicz, Bronisław Bohatyrewicz, Xawery Czernicki (admiral), Stanisław Haller, Aleksander Kowalewski, Henryk Minkiewicz, Kazimierz Orlik-Łukoski, Konstanty Plisowski, Rudolf Prich (murdered in Lviv), Franciszek Sikorski, Leonard Skierski, Piotr Skuratowicz, Mieczysław Smorawiński and Alojzy Wir-Konas (promoted posthumously).