If the documents are missing, how does the Honorable Lee Hamilton know which documents are missing?
My guess is that the National Archives updates their inventories on a timely basis. They also noticed Berger behaving suspiciously.
I've read or heard that Berger took an original document, not just copies.
The hour is late. Try googling Berger+national+archives tomorrow.
I think that is that a trick question and I'm not falling for it? LOL!