Silk Road bust
I am willing to believe that The Man operates some of the TOR exit points, but that's likely not enough for pinpoint accuracy. If you look up some of the talks on how Silk Road was busted, you will see that his opsec is what really got him busted. I expect it's the same with this bust and the reason to seal the evidence is to make it look like The Feds have rooted TOR to scare people away from it. Staying anonymous when the Gov is gunning for you with lots of resources means you have to walk the rice paper without leaving a single trace. That's pretty tough.