This work explores the profile of the perpetrators of Nazi genocide as reflected in post-war German trial sentences. It investigates their social background, their ""route to crime"", and their role in the Nazi extermination apparatus. In addition, it studies the post-war prosecution of these genocidal criminals in West Germany. It describes and analyzes the obstacles, ""bottlenecks"", and omissions in the prosecuting policies and presents their statistical record. It examines the way in which post-war German courts dealt with these criminals by an in-depth study of the trial sentences against two specific groups of genocidal perpetrators: the ""Euthanasia"" and ""Aktion Reinhard"" killers. Through a scrutiny of the argumentation of the various courts' sentences in these cases, it presents a detailed picture of the grounds for acquittal, conviction and punishment. It discusses the controversial differentiation of ""murder"" and ""complicity in murder"" with regard to these genocidal perpetrators and highlights the ways in which the courts handled complicated questions, such as acting under superior orders, duress and coercion.