I’m not buying much, if any, of this story. The FBI has been known to groom potential ‘terrorists’, catch them before they can act, and then toot their own horns for a job well done. And by groom, I mean nudging unstable people towards extremism and providing them weapons, vehicles, dates, etc. to carry out an attack.
Knowing that the FBI does the things I mentioned also leads to a disturbing question: how many successful mass attacks in the US were the result of FBI involvement? Is it a nonzero number?