During the war Dachau concentration camp became a place of mass murder. Beginning in October 1941, thousands of Soviet prisoners of war were brought to Dachau and shot. Also, others who the Gestapo, the Secret Police ordered to be executed, were transported to Dachau and killed.
A large number of prisoners were misused by SS doctors for medical experiments. There were high altitude experiments, cooling and freezing experiments, a series of malaria experiments and others. An unknown number of prisoners died excruciating deaths.
So-called invalid transports began in January 1942. More than 3000 prisoners were taken to the former sanatorium at Hartheim castle near Linz, and murdered there with Carbon monoxide.
There were 30,000 registered deaths in the Dachau concentration camp. Additional, thousands who were not registered were murdered in Dachau. The prisoners died of starvation, sickness, exhaustion, degradation, beating, and torture. They were shot, hanged and killed with injections.
In1942 a gas chamber was also built in the Dachau concentration camp, but inexplicably, it was not used. It was located within the new crematorium, a larger building whose construction with four ovens became necessary when the first crematorium, which had only one oven, proved inadequate.
With the victorious advances of the Allied troops, more and more concentration camps were evacuated by the SS. The prisoners were transported to camps in territory still under Nazi control. On these week-long transports, usually walking, thousands of prisoners lost their lives because of sickness, weakness, starvation or beating by the SS, or when they could no longer walk, they were shot by the SS guards.
The number of prisoners in Dachau concentration camp multiplied, and by December 1944 catastrophic conditions reigned. The barracks were hopelessly overcrowded, a typhus epidemic took thousands of lives.
At the end of April, the SS began to evacuate subsidiary camps. An unknown number of prisoners lost their lives during these evacuations. They were killed during airplane attacks on train transports or they were murdered by the SS before the evacuation.
On April 27, 1945, approximately 7,000 prisoners from the main camp in Dachau were sent on a march towards the Alps in the south.
On April 28, 1945 most of the SS abandoned the camp. One day later, on April 29, 1945, Dachau was liberated by units of the US Army.
A few days before the liberation there were more than 67,000 Dachau concentration camp prisoners. Half of them were in the main camp at Dachau, the remainder in the subsidiary camps and work detachments
(from the official Dachau web site)