A/HRC/13/42* page 53 there being any discernible “fingerprints” of a United States Government operation, as well as the filing of “dummy” flight plans. The experts were made aware of the role of the CIA chief aviation contractor through sources in the United States. The modus operandi was to charter private aircraft from among a wide variety of companies across the United States, on short-term leases to match the specific needs of the CIA Air Branch. Through retrieval and analysis of aeronautical data, including data strings, it is possible to connect the aircraft N63MU with three named American corporations, each of which provided cover in a different set of aviation records for the operation of December 2002. The aircraft’s owner was and remains “International Group LLC”; its registered operator for the period in question was “First Flight Management”; and its registered user in the records of the Eurocontrol Central Route Charges Office, which handles the payment of bills, was “Universal Weather”. Nowhere in the aviation records generated by this aircraft is there any explicit recognition that it carried out a mission associated with the CIA. Research for the present study also made clear that the aviation services provider Universal Trip Support Services filed multiple dummy flight plans for the N63MU in the period from 3 to 6 December 2002. In a report, the CIA Inspector General discussed the interrogations of Abu Zubaydah and Abd al-Rahim al-Nashiri. Two United States sources with knowledge of the high-value detainees programme informed the experts that a passage revealing that “enhanced interrogation of al-Nashiri continued through 4 December 2002” and another, partially redacted, which stated that: However, after being moved, al-Nashiri was thought to have been withholding information”, indicate that it was at this time that he was rendered to Poland. The passages are partially redacted because they explicitly state the facts of al-Nashiri’s rendition details which remain classified as “Top Secret”.202 117. Using a similar analysis of complex aeronautical data, including data strings, research was also able to demonstrate that a Boeing 737 aircraft, registered with the Federal Aviation Administration as N313P, flew to Romania in September 2003. The aircraft took off from Dulles Airport in Washington, D.C. on Saturday 20 September 2003, and undertook a four-day flight “circuit”, during which it landed in and departed from six different foreign territories - the Czech Republic, Uzbekistan, Afghanistan, Poland, Romania and Morocco - as well as Guantanamo Bay, Cuba. Focus was also placed on a flight between the two listed European “black site” locations - namely from Szymany (Poland) to Bucharest - on the night of 22 September 2003, although it was conceivable that as many as five consecutive individual routes on this circuit beginning in Tashkent, concluding in Guantanamo - may have involved transfers of detainees in the custody of the CIA. The experts were not able to identify any definitive evidence of a detainee transfer into Romania taking place prior to the flight circuit. 118. In its response to the questionnaire sent by the experts, Poland stated that: On 11 March 2008, the district Prosecutor’s Office in Warsaw instituted proceedings on the alleged existence of so-called secret CIA detention facilities in Poland as well as the illegal transport and detention of persons suspected of terrorism. On 1 April 2009, as result of the reorganization of the Public Prosecutor’s Office, the investigation was referred to the 202 CIA Inspector General, Special Review, op. cit, paras. 76 and 224.