Earlier in 2016, the FBI has started a war against pedophiles on the Tor network. One of the reasons that fueled the rage was when the FBI managed to seize Playpen's server in 2015, and allowed the site to run for a brief 12 days more to get pedophiles IP addresses, before finally shutting the site down.
It was claimed that up to 80 percent of Deep Web's "darknet" activity on Tor was related to child pornography.
Playpen was a site that hosted the largest collection of child porn. The agency used a "network investigative technique" (NIT) as a way to ensnare site users.
It was then revealed that Playpen wasn't the only one. According to a document obtained by the American Civil Liberties Union, the FBI has managed to seize and ran a lot more.
Sarah Jamie Lewis, a security researcher, said that "it's a pretty reasonable assumption" that the FBI was, at one point, running nearly half of all known child porn sites hosted on Tor-hidden services.
She ran OnionScan which is an analysis tool that uses bots to map out the dark web in order to look for vulnerabilities. From her research that went from April 2016 to August, she mapped many unique CP-related sites on Tor, and the FBI authorized to run a total of 23 of such websites.
Read: Freedom Hosting NIT Affidavit
"Doing the math, it's not zero sites, it's probably not all the sites, but we know that they're getting authorization for some of them," she said. "I think it's a reasonable assumption - I don't think the FBI would be doing their job if they weren’t."
Lewis is a former computer scientist at the British intelligence and security organization Government Communications Headquarters (GCHQ).