Controversy preceded General David Petraeus' first day behind the director's desk at the Central Intelligence Agency.
Speaking on Monday, the Council of Europe's Human Rights Commissioner Thomas Hammarberg urged continental governments to reveal the locations of CIA black sites.
These U.S.-operated facilities are used for enhanced interrogation -- often considered to be torture -- of terror suspects.
According to Hammarberg, the CIA has interrogation sites in Poland, Romania and Lithuania, among other places, where governments have allowed the U.S. to break humanitarian laws.
Darkness still enshrouds those who authorized and ran the black sites on European territories, he said, CNN reports. The full truth must now be established and guarantees given that such forms of co-operation will never be repeated.
Gen. Petraeus assumes the role of CIA director on Tuesday, taking over from acting head Michael Morell, who succeeded Leon Panetta in July. Under Panetta, the office admitted to having the off-shore interrogation centers, but denied any illegal activity.
Khalid Sheikh Mohammed, often called the mastermind of the Sept. 11 terror attacks, was purportedly kept in a Polish black site between 2002 and 2003.
On Thursday, court documents revealed that the U.S. government contracted a luxury jet company to fly high-level suspects to international interrogation centers. According to the filings, jets brought alleged terrorists to black sites in Kabul, Afghanistan; Bangkok, Thailand and Bucharest, Romania, and also handed over suspects to local interrogators in Cairo, Egypt; Damascus, Syria; Amman, Jordan; and Rabat, Morocco.
Through rendition, the CIA captured individual suspects on foreign territories, often with the assistance of the local security services, and flew them to some specific third countries to be interrogated, Hammarberg said on Thursday.
This technique kept the suspects outside the reach of any justice system and rendered them vulnerable to ill-treatment.
Panetta said in 2009 that all black sites had been closed, but the secrecy and opacity surrounding the program is still troublesome. For Hammarberg, the U.S., as well as the foreign governments involved, can only clear their consciences once a full record is disclosed.
Even a small level of accountability will take steps to assure that no government is allowed to operate a secret prison, either domestically or abroad.