Human rights activists say a Saudi citizen was once held at an alleged secret CIA detention site in Lithuania and are urging the Baltic government to re-open an investigation.

The human rights organization Reprieve says Mustafa al-Hawsawi, who is currently being held in Guantanamo Bay, was secretly brought to Lithuania in March 2004 and held there until September 2006.

Reprieve lawyer Sarah Fulton says Lithuanian authorities should reopen their investigation into the country's involvement in the CIA black site that many believe was used to torture terrorist suspects and extract information.

Activists said Thursday the information came to light after studying new data on secret flights to and from Lithuania.

Lithuanian lawmakers have determined that the CIA could have established two prisons with the help of the country's security service.