Comment by posterboy
technicly this is the only comment in this chain that is relevant to the featured article, but it's technicly so incomplete that it's almost wrong, I can tell from having read the thread and knowing next to nothing else about how TOR works.
They don't have plausible evidence to subpoena the guard node if a middle node only sees encrypted traffic. They would also need to control the exit nodes which communicate with the target's host or they simply control the host as a honeypot.
Because the victim was an onion server, they could make it generate new connections at will. They used timing correlation to determine their node was the middle node for their connection.