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New details have emerged about a CIA prison in Poland that was allegedly at the center of the United States’ controversial policy of extraordinary rendition in the years after the September 11 attacks. A lengthy report in The Washington Post Thursday has resurrected a five-year-old investigation into the collusion of Polish officials with the interrogations of al Qaeda suspects, which, if true, could lead to prosecutions there.

The Washington Post alleges that CIA officials paid Polish intelligence $15 million—handed over in cardboard boxes—in exchange for access to a villa tucked away in the Polish lake district, where operatives ran a secret prison and employed interrogation techniques that many in the international community, included President Barack Obama, have labeled torture.

The alleged site, codenamed “Quartz,” operated from late 2002 to September 2003, after which the detainees housed there were transferred to prisons in Romania, Morocco, and Lithuania before being eventually deposited at the U.S. military prison at Guantanamo Bay, Cuba. Former CIA officials cited in the report described “dramatic positive results” yielded through the CIA’s harsh interrogation techniques. Khalid Sheik Mohammed, who masterminded the attacks of Sep. 11, 2001, was among the detainees, and was waterboarded 183 times at the facility.

Polish prosecutors said Friday that the Washington Post report may contain new evidence to be used into their investigation into what role Polish officials played in creating or operating the facility. The European Court of Human Rights is expected to issue a decision this year on whether or not Poland violated international law by allowing an American torture facility to operate on its soil. Polish officials have denied the existence of a secret CIA prison in the country.

The debate over controversial interrogations practices employed by the United States after September 11, 2001, is set to be reopened, the Post reports, as the Senate Intelligence Committee prepares to release portions of a classified 6,000-page report on the program.

The CIA declined to comment to The Washington Post on the report, as did Polish officials.

[The Washington Post]