Pirate Bay co-founder Gottfrid Svartholm Warg’s detainment in Denmark has been extended by four weeks by the Court of Fredriksberg, a court spokeswoman said Thursday.

Svartholm Warg, a 20-year-old Danish man and several other currently unknown perpetrators are suspected of hacking the mainframe of IT service provider CSC in Denmark, Judge Kari Sørensen of the Fredriksberg court said in an email. The mainframe contained sensitive and confidential information belonging to private and public institutions, she said.

The 20 year old is in custody, but his name has been withheld by local media for privacy reasons. (The IDG News Service has decided to adhere to local custom and withhold the name.)

The men are suspected of copying and downloading a “great number of files” containing, among other things, information from the Danish police, Sørensen said.

Because the court’s hearing took place behind closed doors, Sørensen said she couldn’t elaborate on what else was discussed. The court, however, has found that there is reasonable suspicion that he is guilty and will leave the country if not held in custody, she said.

Svartholm Warg was extradited from Sweden to Denmark in November last year, where he was serving a one-year sentence for hacking the mainframe of IT consulting firm Logica, which provided tax services to the Swedish government. When he was extradited, there was still one month remaining on his sentence, which can be dealt with later if necessary, the Swedish prosecution has said.

Since then, he has been held in Denmark, where his detainment was extended on Dec. 18 and again on Wednesday when the court ordered him detained until Feb. 5. Police have detained Svartholm Warg on basis of their suspicions, but have not indicted him yet and are still gathering evidence, Sørensen said.

Before he was tried in Sweden and extradited to Denmark, Svartholm Warg was arrested in Cambodia in 2012 and subsequently extradited to Sweden to face hacking charges.

Svartholm Warg’s Danish lawyer, Luise Høj, did not immediately respond to a request for comment.