The site the men allegedly visited was a Tor hidden service, which supposedly would protect the identity of its users and server location. What made the case stand out was that the Federal Bureau of Investigation (FBI) had used a hacking tool to identify the IP addresses of the individuals.

The case received some media attention, and snippets of information about other, related arrests started to spring up as the year went on. But only now is the true extent of the FBI's bulk hacking campaign coming to light.

In order to fight what it has called one of the largest child pornography sites on the dark web, the FBI hacked over a thousand computers, according to court documents reviewed by Motherboard and interviews with legal parties involved.

"This kind of operation is simply unprecedented," Christopher Soghoian, principal technologist at the American Civil Liberties Union (ACLU), told Motherboard in a phone interview.