Fritz Klein was born in Feketehalom, Austria-Hungary (now Codlea in central Romania), on 24 November 1888.
Klein was considered a Volksdeutscher, or ethnic German. He studied medicine at the University of Budapest and completed his military service in Romania, finishing his studies in Budapest after World War I. He lived as a doctor in Siebenbürgen
In 1939, as a Romanian citizen he was drafted into the Romanian army, where after the outbreak of the war with the Soviet Union in 1941 he served as paramedic on the eastern front. In May 1943, Romanian dictator Marshal Antonescu, on a demand from Hitler to release ethnic Germans in the Romanian Army, drafted them into the German army. Hence Klein became a soldier in the Waffen-SS, was listed in the SS-Personalhauptamt, and was posted to Yugoslavia.
On 15 December 1943, he arrived in Auschwitz concentration camp, where at first he served as a camp doctor in the women’s camp in Birkenau. Subsequently, he worked as a camp doctor in the Gypsy camp. He also participated in numerous selections (“Selektionen”) on the ramp. In December 1944 he was transferred to Neuengamme concentration camp, from where he was sent to Bergen-Belsen concentration camp in January 1945. He remained at the camp with commandant Josef Kramer and assisted in handing it over to British troops. Klein was imprisoned and required to help bury all unburdened corpses in mass graves. The British Army Film and Photographic Unit Number 5 Unit photographed Klein standing in a mass grave in a well-known 1945 photo.
When asked how he reconciled his actions with his ethical obligations as a physician, Klein famously stated:
“My Hippocratic oath tells me to cut a gangrenous appendix out of the human body. The Jews are the gangrenous appendix of mankind. That’s why I cut them out.”
Klein and 44 other camp staff were tried in the Belsen Trial by a British military court at Lüneburg. The trial lasted several weeks from September to November 1945. During the trial Anita Lasker testified that he took part in selections for the gas chamber.
Dr. Fritz Klein was sentenced to death and hanged, age 57, at Hamelin prison by Albert Pierrepoint on 13 December 1945