The intelligence services penetrated the Bremen SPD during 1934. In November 1934 Hermine Berthold and Anna Stiegler, along with a large number of party comrades were betrayed to the authorities and arrested. The charge was the usual one of "preparing to commit high treason" ("Vorbereitung zum Hochverrat"), and the sentence was a four year jail term. By the time of her trial and sentencing Berthold had already been held in "investigatory detention" at Bremen's "Ostertorwache" (as the establishment was then known). The next three years she spent at the women's prison at Lübeck-Lauerhof. Here she became friendly with the only communist from Bremen being held in Lübeck, Käthe Popall. After 1945, throughout West Germany, the relationship between the SPD and the Communist Party, became ever frostier, but in Bremen Hermine Berthold and Käthe Popall would remain the firmest of friends over the decades that followed. In 1938, her sentence expunged, Hermine Berthold was released. A year later, on 1 September 1939, as German and Soviet troops invaded Poland from opposite sides, Berthold was re-arrested because she had failed to comply with conditions imposed by the authorities. In defiance of Gestapo threats, she had continued to make contact with (politically inclined) friends from the pre-Nazi years. Three months after the re-arrest, to her surprise, she was released again. This seems to have been because, directly before her fre-arrest, her husband had suffered a fatal accident in the port, where he had evidently still been employed.