An amateur rocket group, the VfR, co-founded by Max Valier, included Wernher von Braun, who eventually became the head of the army research station that designed the V-2 rocket weapon for the Nazis. When private rocket-engineering became forbidden in Germany, Sander was arrested by Gestapo in 1935, convicted of treason, sentenced to 5 years in prison, and forced to sell his company. He died in 1938.
