Title: Dvazhdy nevidimyĭ front
Subjects: Intelligence service, Secret service, World War, 1939-1945, Intelligence officers, Soviet Union. Narodnyĭ komissariat vnutrennikh del, History, Soviet Union. Народный комиссариат внутренних дел, Soviet Union, Military intelligence
Places: Leningradskai͡a oblastʹ, Russia (Federation), Ленинградская область