http://www.lewrockwell.com/lewrockwell-show/2012/02/07/253-secret-police-murder-and-cover-up/
If you haven't listened to this podcast, do yourself a favor and listen to it. Its pretty amazing. Confirmed that the FBI actually knew about the bombing prior and possibly had undercover agents involved.
The FBI took the surviellence tapes and has never released them even after a judge ording them to do so.
Completely amazing that the FBI was able to get away with this.