Either this investigation is legitimate, or it is a magician’s hat.
Sapere Aude

If you’re familiar with how a Grand Jury actually works, their job is to decide if there’s enuff evidence to warrant an indictment against a defendant. Of course according to your “logic”, no one, not even a Grand Jury, chosen at random, can be “trusted”! 
So for that matter, how do we know we can trust you?!!;-p

Federal Grand Juries indict 99.99 percent of the time