There is no simple answer to this question, as the level of knowledge about the extermination camps among German citizens varied greatly. During the war, much of the information about the Nazi regime's atrocities, including mass deaths through extermination, were known only by Nazi officials directly responsible for these matters. However, as evidence regarding Nazi crimes began to circulate during later stages of the Second World War, many German citizens grew suspicious of such activities. After the defeat of Nazi Germany and through investigative inquiries, war trials, documentaries, etc., more evidence surfaced leading people to believe mass murders took place with knowledge from certain ranks or even directly authorized by Hitler and officials close to him.