Operation Pacifier had the FBI go after a child porn TOR site by compromising the site and uploading a flash file embed, which due to an "accidental" bug in the flash plugin for the official Tor browser bundle, had Flash dialing home outside of TOR.
(Yes, this means that the US Government officially ran a Child Porn distribution service for around 2-3 weeks. They could not remove any content or it would let people know. They could not stop uploads or it would let people know. Instead, each page delivered a flash file that was dialing home the user, their real IP, and what they were doing on the site.)
That whole thing was particularly fucked up, because they got a Magistrate Traffic Court Judge to approve the warrant despite a bunch of district court judges being in the same office building because the warrant was literally "Please let us hack an unlimited number of people in an unlimited number of jurisdictions for an unlimited amount of time," which is a blatant 4th Amendment violation and the District Court judges would have told them to fuck off.
When judges started tossing the cases because of it, the FBI had the supreme court change the rules (via Rule 41) to state that if you use the internet, the fourth amendment doesn't apply to you, because
won't someone think of the children and you having privacy rights makes the FBI's jobs
hard. Among the other pants on head insane things this chase changed is the FBI can literally just fine some part time traffic court judge to get them to approve a wiretapping warrant for anyone, anywhere, anytime, jurisdiction be damned, because again,
the constitution just makes their jobs too hard.
Wanna spy on someone in California? Find some redneck judge in Alabama who wants to stick it to the commies. Wanna spy on someone in Alabama? Ask an friendly traffic judge in New York City to let you spy on the "evil alt-right militias."
In December 2014, the FBI received a tip from a foreign law enforcement agency that a Tor Hidden Service site called “Playpen” was hosting child pornography. That tip would ultimately lead to the largest known hacking operation in U.S. law enforcement history. The Playpen investigation—driven by...
www.eff.org
Edit: You should all be watching the Kiwi Farms website source for any new additions very, very fucking close.