 Blumenfeld's Zionistische Vereinigung für Deutschland (Zionist Federation of Germany) persuaded her to use this access to obtain evidence of the extent of antisemitism, for a planned speech to the Zionist Congress in Prague.This research was illegal at the time.Her actions led to her being denounced by a librarian for anti-state propaganda, resulting in the arrest of both Arendt and her mother by the "Gestapo".