Irish authorities will not prosecute Eric Eoin Marques, who is wanted on four charges of distributing child pornography. His extradition to the U.S. is sought by the FBI, but it is unclear whether Ireland will hand him over.

Marques has been called the “largest facilitator of child porn on the planet” through hosting sites on the “dark” internet.

Marques is accused of running Freedom Hosting, which uses anonymizing tool Tor, to create dark internet sites. Forums hosted by Freedom Hosting allowed users to anonymously share child pornography.

In November, the 28-year-old dual U.S.-Irish national said he would plead guilty to a series of charges under Irish law. Ireland’s Director of Public Prosecutions (DPP), Claire Loftus, has said that she will not bring proceedings against him in Ireland. She has not explained her decision.

Marques, who has no criminal history, would have faced a maximum 14 year sentence, which would be significantly reduced by his early guilty plea, in Ireland. In contrast, he faces a total of 100 years if found guilty in the U.S., according to the FBI. The U.S. sentence is equivalent to four life sentences in Ireland.

In the U.S. each charge is punished by a sentence of between 20 and 30 years and the sentences run consecutively. In Ireland the sentences run concurrently.

Marques’ lawyers are expected to argue that the U.S. sentences for similar charges are too harsh in comparison with Ireland’s. In addition, the Justice Minister can refuse an extradition hearing where the DPP has decided not to bring proceedings against the accused.

The extradition hearing is expected to be held early next year. 

Marques was arrested at his Dublin home in August 2013 on four charges of distributing and promoting child pornography. He was denied bail and is considered a “flight risk” by the Irish police and the FBI. In November he appeared before the High Court, which heard that large payments had been transferred to accounts in Romania. His computer’s browser history revealed that he had searched for information on Russian visas.

His arrest coincided with the disappearance of many “hidden services” on the anonymous network Tor. Tor uses an ‘onion’ system to hide its members’ IP addresses from the police, which makes it almost impossible to identity the physical location of the culprit. Tor also protects its users from traffic analysis.