In August, 1937, her husband was appointed commandant of Buchenwald. She went with him and became a SS-Aufseherin (overseer) at the camp.
Known as the "Bitch of Buchenwald" she liked to ride through the camp where she selected prisoners who displeased her to be whipped by Schutz Staffeinel (SS) guards. She also collected lampshades and gloves made from tattooed skins of specially murdered concentration camp inmates.
At the end of the war Koch was arrested and charged with "participating in a common criminal plan for encouraging, aiding, abetting and participating in the atrocities at Buchenwald." In 1947 Koch was found guilty and was sentenced to life-imprisonment.
After serving only two years General Lucius D. Clay, the military governor of the American zone in Germany, ordered her release. As a result of the international condemnation this decision received, Koch was re-arrested and in January 1951, was again sentenced to life-imprisonment. Isle Koch committed suicide in Aibach Prison on 1st September, 1967.