Just a quibble, but I think Trump is looking for law-and-order types, as opposed to "Trump supporters" for the purportedly non-political positions in the DOJ and FBI. AG/DAG is a political position, and FBI director is semi-political. The actual front line management in both is supposed to be apolitical, IMO.
Right now, the whole hierarchy seems infested with political animals left over from the Obama administration.
Well President Trump is doing house cleaning.