What’s the reason FBI so involved in this?
if you are a cabinet level officer and there’s some hankypanky going on around you a federal police agency (FBI, Tmen, ATF, Postal Inspection Service ) will be looking into it.
The FBI are looking to burnish the reputation of the BATFE and TSA.
There's certainly more effort being put into finding out about this stupid affair than there is for finding the truth about Benghazi.