Because Mr. Krebs was doing so with good effect and as a private individual he did not face the legal firewalls in place to prevent LEOs taking such actions for

Because Mr. Krebs was doing so with good effect and as a private individual he did not face the legal firewalls in place to prevent LEOs taking such actions for corrupt or ill intent or blow investigations. I would be interested in what legal firewalls in particular exist - anyone have references? My own guess would be that "don't blow the investigation" would be the catch-all phrase used to explain this situation (even if there is not investigation at time X). It seems as if the institutional mandate of law enforcement is 99% catch criminals, 1% stop crimes without catching criminals. So no one wants to be tasked in efforts to merely stop a theft and not catch a thief. This seems much in line with the push to "get tools to catch bad guys" by weakening encryption, even if said weakening would result in many more crimes.