Playpen was "the largest remaining known child pornography hidden service in the world," according to the FBI. Roughly 137 people have been charged in the sting so far, Motherboard says. On Wednesday, a lawyer for one of the defendants won the right to view all of the code that the FBI used during the Playpen operation, apparently including the exploit that bypassed the Tor Browser's security features.

Some civil liberties groups are concerned about the FBI's methods in this case because the bureau used one warrant to infiltrate more than 1,000 computers around the world. Plus, the defense has argued that the FBI effectively distributed child pornography when it kept the site running in order to send out the hacking tool. A judge ruled in January that the FBI did not engage in "outrageous conduct" when it ran Playpen out of its own servers, Motherboard reports.

We've asked the FBI for comment on this week's order and will update as we hear back.