Some 60,000 persons were deported to the Mittelbau camps between August 1943 and March 1945. The overall number of deaths cannot be precisely determined. About 12,000 were officially registered in the SS files. In addition, there were an unknown number of unregistered cases of inmates dying or being killed in the Mittelbau camps, over 5,000 dying persons sent on extermination transports to Lublin and Bergen-Belsen in early 1944 and March 1945, and an unknown number of inmates who did not survive the death marches following the vacation of the Mittelbau camps in April 1945. The names of approximately 1,300 concentration camp inmates whose bodies the American soldiers found in the Boelcke casern during the liberation in April 1945 are also not registered. Even on the basis of a conservative estimate, it can be assumed that at least 20,000 inmates did not survive deportation to Mittelbau-Dora Concentration Camp.