Maybe this is an easy questions to answer. My grandfather was captured by the Russian Army around September 1939 in Janowa (Kostopol District, Wolyn County) and was deported to Russia in 1941. On the basis of the Sikorski-Maisky agreement, he was released on the purpose of joining the Polish Armed Forces in 1941.
I am trying to find out what had happened to him during his imprisonment in Poland and Russia and where he was held. He had told me that the Russians torched him badly and wanted him to renounce his religion, nationality and join the Red Army.
In his Polish/British military records, it states that there is no information about where he was held.
Sorry if it sounds naive but would Russia hold any records of their POWs and would it be worth a try in contacting them?