The Dachau camp was the first concentration camp set up by the Nazi regime. It was created on the site of a former munitions factory 17 km northwest of Munich1. Its opening was announced by Heinrich Himmler on March 21, 1933, and prisoners were brought in the very next day. The camp remained in operation until the arrival of American soldiers in April 1945. When the Americans approached the camp at the time of the Liberation, the German General Staff gave the retaliatory order to kill all the prisoners. But Communist politician Oskar Müller, then head of the camp's resistance committee, decided to secretly free a few prisoners on behalf of the International Red Cross, in order to warn the American soldiers of the camp's exact location and the urgent need to intervene. On April 29, 1945, the 45th Infantry Division of the U.S. Seventh Army liberated the camp. When the American soldiers entered the camp, they were confronted with scenes of horror: prisoners in an appalling state of emaciation, mass graves piled high with shredded bodies. Some American soldiers were so disgusted that they fired point-blank at the officers in charge of the camp (Dachau Massacre). The photos and films taken by the American soldiers and transmitted by General Patton were archived in the report of the VIIth US Army.
René Lévesque (1922-1987), who later became Premier of Quebec, was the "American" war correspondent who accompanied the first patrol discovering the camp. Wikipedia source.