The career of the German physicist Walther Gerlach (1889–1979) spanned two world wars and the changing political systems in Germany in the twentieth century. As a physicist involved in the rapid development of atomic physics and the management of scientific research in Germany during World War II as well as in post-war West Germany, several attempts have been made in the past by historians of science to write his full biography. These projects have, among other foci, asked about Gerlach's role (...) and his position with respect to National Socialism. However, based on his extensive papers preserved in the Deutsches Museum Archive in Munich, none of these projects has so far been conclusive. In this article, we identify evidence for the selective deletion of personal files relating to his first wife and daughter. We argue that reconstructing this lacuna sheds new light on the influence of National Socialist ideology on Gerlach's personal life, making him both a profiteer and a victim of eugenics jurisdiction. (shrink)