Those Who Save Us by Jenna Blum; 2005. Softcover.

For fifty years, Anna Schlemmer has refused to talk about her life in Germany during World War II. Her daughter, Trudy, was only three when she and her mother were liberated by an American soldier and went to live with him in Minnesota. Trudy's sole evidence of the past is an old photograph: a family portrait showing Anna, Trudy, and a Nazi officer, the Obersturmfuhrer of Buchenwald.Driven by the guilt of her heritage, Trudy, now a professor of German history, begins investigating the past and finally unearths the dramatic and heartbreaking truth of her mother's life.