Siegfried Müller (26 October 1920 – 17 April 1983) often called Kongo-Müller was a former German Wehrmacht officer-candidate who fought as a mercenary under Major Mike Hoare in the Congo Crisis.
Siegfried Müller (mercenary) Wikipedia
Siegfried Müller was born in Crossen an der Oder, Germany (now Poland) in 1920. After Hitler Youth and Reich Labour Service, Müller joined the Wehrmacht in 1939, fighting in the campaigns in Poland, France, and on the Russian Front. He claimed to have held the rank of First lieutenant by the end of the war, but this cannot be verified. He was seriously wounded and captured by the Americans.
Released in 1947, he enlisted in the US Army Civilian Labor Group (CLG), an American Labor Service Unit of Germans; then became a Lieutenant in a CLG security unit. He was denied entry to the Bundeswehr in 1956, but found employment with British Petroleum, clearing mines planted by the Afrika Korps in the Sahara Desert during World War II.
Müller emigrated to the Republic of South Africa in 1962 and was recruited as a mercenary with the rank of Lieutenant for the Congo Crisis in 1964. At 44, Müller was the oldest of Mike Hoare's soldiers. He was promoted to Captain after a successful operation to seize Albertville (now Kalemie) and led 52 Commando, a sub unit of No 5 Commando comprising approximately 50 soldiers. He was later promoted to Major.