[edwest2]

If I may add a side note. Depending on whether they were friendly or otherwise, certain buildings were looted and certain documents were confiscated. All sides did what they could in this regard. It is easy to think of sovereign countries in Europe during the war, but the fact is that occupiers used records or hid records for the purpose of "legal" maneuvering. And "political" enemies could end up in prison.


As far as intelligence, foreign embassies in Europe were sources of intercepted intelligence. Of course, buildings were bombed by accident but there are documented cases where some targets were not bombed due to their post-war value.


The mystery of what Allen Dulles was doing in Bern, Switzerland may never be fully explained. He was an attorney, nothing more. His duties with the OSS, or Office of Strategic Services, seem to be far beyond the knowledge of a civilian. After all, most of what they did was classified. According to their operational head, William Donovan, "We killed people and blew up things." Yes, that and more. But I have not seen a single in-depth account of OSS operations.


Before the end of the war, the US did hide sensitive information that included more than secrets. It was clear that the Russians were going to keep as much land as possible in Europe and keeping them in the dark regarding what was known by the Allies was a requirement. As far as German records, I have read an account where some documents that were among those to be returned to Germany were found in another location, separate from the rest.


In Germany, "private collections" are known as well. A book has been written about German negotiations with the US to get captured documents returned. These negotiations occurred over decades.