Complex sentence: Until March 1946 he was held in Butyrka then in Unzha camp (station Sukhobezvodnaya Gorky Railway), from 25 May 1949-at the MVD Ozerlag (LakeLabourCamp) Special Camp № 7, Tayshet, Irkutsk Region.
Split into simpler sentences: Until March 1946 he was held in Butyrka then in Unzha camp (nearest station Sukhobezvodnaya on the Gorky Railway). From 25 May 1949 he was at the MVD Ozerlag (Lake Labour Camp) Special Camp No.7, Tayshet, Irkutsk Region.