who?
Well, the first one will be the lawyer who specified in writing (with signature attesting to the truthfulness) that there were no more classified documents on premises. Ouch. That is a career limiting mistake.

My guess is that he will be flipping like a flap-jack if he wasn't already the source of the inside intel to begin with. Squeeze him hard. He'll cave.
It wasn't racketeering and murder that they got Al Capone on. Eventually they just got him on tax evasion. Whatever works. As long as he spends the final years of his pathetic life in a 8x10 cell. However you need to do it.