There is something I don't understand. From the contents of the "attachment A" it seems like the FBI (or whatever other US agency) "sat" on the code they indir

There is something I don't understand. From the contents of the "attachment A" it seems like the FBI (or whatever other US agency) "sat" on the code they indirectly purchased for 2-3 years (the UPAS) and for several months (the KRONOS), observing the behaviour of Hutchins and "Vinny" and collecting evidence against them. Shouldn't they have somehow acted to prevent the spreading of the malwares?