Over its twelve years as a concentration camp, the Dachau administration recorded the intake of 206,206 prisoners and 31,951 deaths. Crematoria were constructed to dispose of the deceased. These numbers do not tell the entire story, however. Although there is no evidence of mass murder within the camp — by methods other than poor sanitation, deprivation of medical care, withholding of nutrients, medical experiments, or beatings and shootings for infractions of the rules or at random — beginning in 1942 more than 3166 prisoners in weakened condition were transported to Hartheim Castle near Linz and there were executed by poison gas for reason of their unfitness. In 1941 and 1942 an unknown number of prisoners of war from the Soviet Union were executed by shooting at the camp's surrounding firing ranges, some for target practice and for sport.