Barry’s Gramps was found to have a huge 600 page FBI file that was almost entirely redacted when partially released before it was DESTROYED!
http://www.wnd.com/2010/04/139805/
The Feds have no trouble destroying evidence, especially when it comes to FOIAA.
I filed one once regarding the particulars of a government contract, they sent me a CD that was intentionally damaged and unreadable (I’m talking somebody took a key to it and scratched off 50% of the laminate).
It was accompanied by a letter from some apparatchik that said if I had any more questions I should give him a call.
I took the hint that calling him would not be a good idea.