I think axo's line of thinking is something along the lines of.

If the suspect wasnt fbi/cia/atf who the heck ever. They would release the footage. But if it shows a government agent. We will never see it.

Considering the past with most of these departments, its not a far stretch to assume they wanted to detonate it, they just couldnt find a easy patsy to blame it on. Or the patsy backed out last second or was even arrested for waltzing in the building after the doors opened. Many variables here lol.