[a fool in paradise]

KTLA said one of his 4 felony charges from this arrest is “the sale and transportation of a destructive device”

Were they already investigating him before the traffic stop?

[crusher2013]

Must have been. The Police don’t pull you over and search without some reason/suspicion.

[Paladin2]

Were the FIB funding him?

[Cementjungle]

Were they already investigating him before the traffic stop?

The FBI probably knew about him for 3 years. Dumb luck that he got nailed in a routine traffic stop.