Out of 2,000 arrested by the Soviet forces , about 600 have disappeared . They are presumed to have been executed and buried in an unknown location in present-day Russia or Belarus . Polish Institute of National Remembrance has declared the 1945 Augustów roundup " the largest crime committed by the Soviets on Polish lands after World War II " . The crime has been called " second Katyn " , " small Katyn " , " little Katyn " or " Podlaski Katyn " in today 's Poland , in reference to the Katyn massacre that occurred in 1940
Katyn massacre
Katyn massacre
Augustów roundup