On September 4, 1942, Hans Max Haupt, along with Erna Emma Haupt, Walter Otto Froehling, Lucille Froehling, Otto Richard Wergin, and Kate Martha Wergin, were indicted by a grand jury in the U.S. District Court for the Northern District of Illinois for treason against the United States.

[2] He sentenced Erna Max Haupt (Hans' wife), Lucille Froehling, and Kate Martha Wergin to 25 years in prison and imposed a $10,000 fine.

On July 23 the court released its decision, written by Circuit Judge James E. Major, in which it reversed all of their convictions and ordered a second trial.

[3] A new trial commenced, and Haupt was once again found guilty of treason, to which Judge John P. Barnes sentenced him to life imprisonment and imposed a $10,000 fine.

The Supreme Court granted Haupt's petition, and held oral arguments on November 21 and 22, 1946, and released its opinion on March 31, 1947.