A man in Ireland believed to be behind Freedom Hosting, the biggest service provider for sites on the encrypted Tor network, is awaiting extradition on child pornography charges, reports The Independent. Denied bail until there is a ruling on the extradition request, Eric Eoin Marques has been described by an FBI special agent as “the largest facilitator of child porn on the planet,” and faces up to 30 years in prison if tried in the US.

The Tor (short for “the onion router”) network is designed to anonymize traffic, with a layered structure by which users re-route each other’s requests through a web of computers multiple times, obfuscating the identity of the sender and receiver. Numerous reports claim that Freedom Hosting users were targeted using a JavaScript exploit of vulnerabilities in the Tor Browser Bundle, a self-contained open source web browser built from Mozilla’s Firefox that makes it easy for ordinary users to access the Tor network. With a user’s browser compromised it would be possible to make the affected computer request a webpage outside of the Tor network, reporting its non-Tor IP address in what’s known as a “correlation attack” — in this case, sending requests to a Verizon IP address, according to The Daily Dot. It’s believed that by compromising Freedom Hosting, the attackers have knocked out half of Tor’s hidden services — websites and other services like email (Tormail) that are only accessible over the Tor network.

Freedom Hosting is the largest and best-known hidden service provider, hosting a number of prominent darknet destinations, including well-known child pornography sites as well as Silk Road, an online marketplace for drugs and other illegal merchandise. Its high profile as a safe haven for child porn earned it the ire of internet activist collective Anonymous, which used DDoS attacks to temporarily take it offline in 2011. Marques is scheduled to appear in Ireland’s High Court on Thursday, reports The Independent.