Photo Dr. Franz Josef Messner.  Private archiv Volker Sartorti, Elmshorn, Germany. Wikipedia. Online, {https://commons.wikimedia.org/wiki/File:Dr._Franz_Josef_Messner.jpg}, (Stand 10.12.2025).

Murdered in the gas chamber of the Mauthausen concentration camp. Franz Josef Messner's resistance activities and fate
Franz Josef Messner took over the management of the Semperit Works in Vienna in 1937. Following the annexation of Austria in 1938, he established close connections with the resistance group centered around the chaplain Heinrich Maier and Walter Caldonazzi.
Starting in 1942, he used his business-related trips abroad to pass on information about German arms factories to the US intelligence service (OSS).
Messner was arrested on March 29, 1944, and on October 27/28, 1944, was sentenced to death by the People's Court for high treason, among other charges. However, the execution of the sentence was initially postponed due to his Brazilian citizenship.
Instead, he was transferred to the Mauthausen concentration camp, where the camp commandant Franz Ziereis (1905 - 1945) ultimately ordered his killing. Franz Josef Messner was murdered there on April 23, 1945.