Stasi's spies helped a lot, as told in Macrackis' book on the East German intelligence service: https://books.google.com/books?id=LLZJk4FrqwwC https://books.goo

Stasi's spies helped a lot, as told in Macrackis' book on the East German intelligence service: https://books.google.com/books?id=LLZJk4FrqwwC https://books.google.com/books?id=LLZJk4FrqwwC