Friedrich Rehmer was the son of a metalworker, born in Berlin on June 2, 1921. Rehmer attended school until the age of 15, worked in a factory for two months, and then attended evening classes to complete his school education. He was drafted into the Wehrmacht in June 1941 and wounded on the Eastern Front in October 1941. Rehmer was admitted to the reserve military hospital in Berlin-Britz in January 1942. From there, he returned to the examination preparations interrupted by his drafting. Through his evening classes he met Ursula Götze, Otto Gollnow, Fritz Thiel, and Liane Berkowitz, who put him in contact to the circle around John Rittmeister and Harro Schulze-Boysen. Rehmer distributed illegal texts among the patients at the military hospital. In 1942 he became engaged to Liane Berkowitz, who was pregnant with his daughter. Friedrich Rehmer was arrested on November 29, 1942, sentenced to death by the 2nd Senate of the Reich Court Martial on January 18, 1943, and murdered in Berlin-Plötzensee on May 13, 1943.