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A Guantanamo detainee who allegedly revealed valuable information about 9-11 mastermind Khalid Sheikh Mohamed is suing Poland in a European court.

Abu Zubaydah's lawyers say he was held in a CIA black site in Poland, which they say has withheld critical information needed to investigate his case. He was allegedly held in Poland between 2002 and 2003.

Abu Zubaydah has been held by U.S. authorities for more than a decade without being charged and is now in a secret location at the U.S. prison camp. His lawyers say he was repeatedly subject to water-boarding — simulated drowning — by U.S. interrogators.

The lawsuit against Poland was filed Monday by the London-based legal charity Reprieve at the European Court of Human Rights in the French city of Strasbourg.