The question about the fate of the Polish prisoners was raised soon after Operation Barbarossa began in June 1941. The Polish government-in-exile and the Soviet government signed the Sikorski–Mayski agreement, which announced the willingness of both to fight together against Nazi Germany and for a Polish army to be formed on Soviet territory. The Polish general Władysław Anders began organizing this army, and soon he requested information about the missing Polish officers. During a personal meeting, Stalin assured him and Władysław Sikorski, the Polish Prime Minister, all the Poles were freed, and not all could be accounted because the Soviets "lost track" of them in Manchuria. Józef Czapski investigated the fate of Polish officers between 1941 and 1942.