The Forex cartel story is fascinating to me.

As you described the story, my first thought was “how did the authorities figure this out?” And it turns out you wondered the same thing. What methods did they use to get enough incriminating evidence for the charges?

If authorities used snooping, back doors, massive brute force decryption or other such techniques, I would guess that they’re not going to disclose it for fear of public backlash. It would be similar to the military’s fear of disclosing the existence of ENIGMA by preventing an attack they could only know about if they could read the enemy’s communications.

So, it would seem in the authority’s best interest to make sure the story had some element of easy explanation like one of the conspirators turned on the other, or external actions have them enough for a warrant for one of their computers or something like that.