In July 1945, the Red Army units, assisted by Polish Army forces and officers of the Security Office (Urząd Bezpieczeństwa, UB) and its agents, conducted a major pacification operation in the area of the Augustów Forest (Puszcza Augustowska), referred to as the Augustów Roundup (Obława Augustowska). On the Soviet side, the operation involved the units of the 50th Army of the 3rd Belarusian Front, the NKVD Internal Troops and officers of the military counterintelligence service SMERSH. Polish officers of the Office of Public Security (Urząd Bezpieczeństwa Publicznego, UBP), the Citizens’ Militia (Milicja Obywatelska, MO) and local informers supported the Soviets as guides and interpreters; they also assisted during interrogations.
The Soviet forces combed the forests and villages to arrest people suspected of contacts with the Polish national resistance movement. The exact dates of the operation proved impossible to establish: it is most frequently placed between 12 and 28 July. In total, several thousand people were detained in the course of the operation; some of them were arrested and tortured during investigation. About six hundred have never been heard of again. Most likely, all of them lost their lives as a result of one Soviet-planned action and should be treated as victims of the Augustów Roundup.
Poland has long made efforts to discover the fate of those who went missing in the operation. They might have been executed and buried in Navumavichi (Naumowicze) near Grodno or transported further east. What is certain is that they were murdered with the approval of top Soviet political authorities.