Paul Blobel (13 August 1894 – 7 June 1951) was a German Sicherheitsdienst (SD) commander and convicted war criminal who played a leading role in the Holocaust. He organised and executed the Babi Yar massacre, the largest massacre of the Second World War at Babi Yar ravine in September 1941, pioneered the use of the gas van, and, following re-assignment, developed the gas chambers for the extermination camps in occupied Poland. From late 1942 onwards, he led Sonderaktion 1005, wherein millions of bodies were exhumed at the massacre sites and extermination camps across Eastern Europe in an effort to erase all evidence of the Holocaust and specifically of Operation Reinhard. After the war, Blobel was tried at the Einsatzgruppen Trial and sentenced to death. He was executed in 1951. Early life Born in the city of Potsdam, Blobel fought in the First World War as an engineer as part of a pioneer battalion, in which by all accounts he served well, being decorated with the Iron Cross first class. After the war, Blobel studied architecture and practiced this profession from 1924 until 1931, when upon losing his job he joined the Nazi Party, the SA, and the SS (he had joined all of these by 1 December 1931). SS career In 1933 Blobel joined the police force in Düsseldorf. In June 1934 he was recruited into the SD Security Service. During World War II, following Operation Barbarossa, in June 1941 Blobel became the commanding officer of [[Sonderkommandos of Einsatzgruppen|Sonderkommando 4a]] of Einsatzgruppe C, active in Reichskommissariat Ukraine. Both, Einsatzgruppen and the Order Police battalions were responsible for massacres of Jews behind the Wehrmacht lines in the Soviet Union. The murder campaign included all political and racial undesirables. In August 1941 Blobel was put in charge of creating a Nazi ghetto in Zhytomyr to enclose around 3,000 Jews who were murdered a month later. On 10 or 11 August 1941, Friedrich Jeckeln ordered him, on behalf of Adolf Hitler, to exterminate the entire Jewish population. On 22 August 1941, the Sonderkommando murdered Jewish women and children at Bila Tserkva with the consent of Field Marshal Walther von Reichenau, commander of the 6th Army. SS-Obersturmführer August Häfner testified at his own trial in the 1960s: Blobel, in conjunction with Reichenau's and Friedrich Jeckeln's units, organised the Babi Yar massacre in late September 1941 in Kyiv, where 33,771 Jews were murdered. In November