Really simple get one of the classified documents from the sender's sent box and compare it to the document on Hillary's private server. The FBI has the real emails now (not print outs) so the metadata should be interesting. .
I heard something the other day on Rush which makes total sense. The FBI is the premier law enforcement agency on the planet. Their integrity and credibility is above all over law enforcement agencies.
If they sell out and don’t bring Hillary’s crimes up, the perception will be they are a corrupted agency and no one in the FBI wants that.