Wikipedia
SS-Totenkopfverbände (SS-TV), rendered (incorrectly) in English as Death's Head Units, was the SS organization responsible for administering the Nazi concentration camps for the Third Reich, among similar duties. While the Totenkopf (skull) was the universal cap badge of the SS, the SS-TV also wore the Death's Head insignia on the right collar when needed; to distinguish itself from other Nazi Schutzstaffel (SS) formations.
The SS-TV created originally in 1933 was an independent unit within the SS with its own ranks and command structure. It ran the camps throughout Germany and later, Nazi-occupied Europe. Camps in Germany included Dachau, Bergen-Belsen, and Buchenwald; camps elsewhere in Europe included Auschwitz- Birkenau in German occupied Poland and Mauthausen in Austria among the numerous other concentration camps, and death camps handled with the utmost of secrecy. The extermination camps' function was genocide; they included Treblinka, Bełżec, and Sobibór built specifically for Aktion Reinhard, as well as the original Chełmno extermination camp, and Majdanek which was fitted with mass killing facilities, along with Auschwitz. They were responsible for facilitating what the Nazis called the Final Solution, known since the war as the Holocaust; perpetrated by the SS within the command structure of the Reich Main Security Office subordinate to Heinrich Himmler, and the SS Economic and Administrative Main Office or WVHA.
Also, at the outbreak of World War II one of the first combat units of the Waffen-SS, the SS Division Totenkopf, was formed from SS-TV personnel. It soon developed a reputation for brutality and fanaticism, participating in war crimes such as the Le Paradis massacre in 1940 during the Fall of France. On the Eastern Front the mass shootings of Polish and Soviet civilians in Operation Barbarossa was the work of special task forces known as SS-Einsatzgruppen, which were organized by Heinrich Himmler and Reinhard Heydrich.