I am trying to help my mother-in-law find out information about her fathers birth father, her Grandmother passed away taking the secret with her. Her father's name is Joachim Sauck. His mother's name is Elsie Kruger. We do not know what his last name was on his birth certificate when he was born. Elsie married Condrad Sauck and he adopted Joachim in the summer of 1935 and change his name to Sauck.
Joachim was born November 14, 1934, in Landsberg an der Warthe, possibly Lubuskie (Poland at the time). The street he grew up on was Landsburger Str. The province was Brandenberg. Somehow, part of this info has been changed because of the war and borders changing between Poland and Germany. The Province is now called Munich.
Elsie Kurger was born in Russia bordering Poland and Germany. Condrad Sauck was born in Germany, and he had a brother that was high up in the Gestapo.
This is all the information my mother-in-law has been able to get from her father since he does not know much, cause his mother would not tell him anything about his real father.