People's Police
After World War II, in 1947, Riedel joined the "Volkspolizei" (People's Police) of German Democratic Republic (East Germany), initially serving as head of the division of the police in Saxony-Anhalt (). In 1949, he became head of the "Volkspolizei-Bereitschaft" (Police Company). He then served in the "Kasernierte Volkspolizei" (KVP—Barracked People's Police), the military units of the "Volkspolizei" (police). On 1 June 1952, he commanded the KVP-"Bereitschaft" in Prenzlau. Riedel then commanded the (6th Motorized Rifle Division) of the Nationale Volksarmee (NVA—National People's Army) from 30 October 1956 to 31 December 1957.