On two occasions (2017 and 2024), the Bundesarchiv, the German federal archive, was consulted, and the same conclusion was reached: Gustav Winter was not affiliated with the NSDAP —the National Socialist German Workers' Party—.
The investigations conducted in the holdings of the Bundesarchiv in Berlin-Lichterfelde, including those of the "Archive relating to National Socialism of the Ministry for State Security of the German Democratic Republic (DDR)" and the "Berlin Document Centre", found no indication in either the central registry or the territorial district registry of the NSDAP.
The official German documentation is clear: there is no record whatsoever of Gustavo Winter's Nazi affiliation.
He indeed appeared on a list of 104 Germans residing in Spain presented by the Allies to the Spanish government. However, the investigations by Doctors Díaz Benítez and García Cabrera refute that he was a German agent responsible for supplying U-boats or that he was in charge of observation posts equipped with transmitters. He did not appear on subsequent lists.
