National Committee for a Free Germany
At the time of his arrest, Heitz was the second-highest ranking German officer taken prisoner by the Allies, behind Paulus. In prison, he vehemently refused to cooperate with the anti-Nazi National Committee for a Free Germany that operated out of the Soviet Union, despite being pressured by the Soviets, who beat him and threatened his family. He died on 9 February 1944 while in Soviet captivity.