The U.S. secret detention and rendition operations in the War on Terror turned suspicion into a chain of cross-border custody, moving Mohamedou Ould Slahi from Mauritania to Jordan, Bagram Air Base, and Guantánamo without a criminal trial. His case reveals how an initial investigation into the Millennium Plot became prolonged detention, how interrogation policy hardened, and how the government’s changing explanations were contested in court and in public.

Policy and the First Detentions

In September 2001, Congress authorized the President to use force against those responsible for the September 11 attacks and those who harbored them. Mohamedou Ould Slahi’s retrospective account places the secret operation that followed within that political moment: he describes it as a program to seize, detain, torture, or kill terrorism suspects, and argues that it lacked a legal basis. That judgment is his own account of the operation, not a judicial finding about the entire program.

His first encounters with detention predated the September 11 attacks. In January 2000, after twelve years abroad, primarily in Germany and briefly in Canada, he was returning to Mauritania when Senegalese police and then Mauritanian authorities detained him at the behest of the United States. FBI agents questioned him about the Millennium Plot to bomb Los Angeles International Airport. Authorities concluded there was no basis to believe he was involved and released him on February 19. He then lived with his family and worked as an electrical engineer in Nouakchott.

On September 29, 2001, Mauritanian authorities detained him for two weeks and FBI agents again questioned him about the Millennium Plot. He was released, and Mauritanian authorities publicly affirmed his innocence. On November 20, police asked him to accompany them for further questioning; he complied voluntarily and drove his own car to the station. Eight days later, a CIA rendition plane took him from Mauritania to a prison in Amman, where Jordanian intelligence services interrogated him for seven and a half months. The move from questioning in his home country to secret imprisonment abroad marked a decisive change in the scale and visibility of his detention.

Transfers and the Expansion of Interrogation

On July 19, 2002, another CIA plane retrieved Mohamedou Ould Slahi from Amman and transferred him to Bagram Air Base. After two weeks of interrogation there, he was flown to Guantánamo with thirty-four other prisoners; the group arrived on August 5. At the time, available reporting did not identify him as a major figure. A Los Angeles Times report described the nearly six hundred detainees then held at Guantánamo as not high enough in al-Qaeda’s command structure to help unravel its organization. The commander of detention operations also questioned whether detainees should be called enemy combatants rather than prisoners of war entitled to Geneva Convention protections. The Pentagon replaced him and increased intelligence operations at the camp.

Interrogation policy was also changing. In September and October 2002, military interrogators established a Special Projects Team and developed a plan for the Saudi prisoner Mohammed al-Qahtani, despite strong objections from FBI and Criminal Investigation Task Force agents. The plan incorporated techniques used by the CIA and, after Defense Secretary Donald Rumsfeld signed its authorization, was applied in a fifty-day round-the-clock interrogation beginning in November. The reported methods included extreme sleep deprivation, loud noise, cold conditions, stress positions, threats, and physical and sexual humiliation. This episode shows the broader institutional conflict over interrogation methods; it is distinct from the later special interrogation plan used against Mohamedou Ould Slahi.

In 2003–2004, Rumsfeld personally approved that special plan for Mohamedou Ould Slahi. His account describes months of extreme isolation, physical, psychological, and sexual humiliation, threats against him and his family, and a simulated kidnapping and rendition. A declassified passage from a 2004 CIA inspector general investigation adds a revealing institutional dimension: the agency had a particular interest in the disposition of detainees who, if not kept isolated, might disclose the circumstances of their detention. The passage does not establish that this rationale alone determined Slahi’s treatment, but it shows that secrecy and control of information were explicit concerns within the detention system.

Allegations, Evidence, and Legal Reversal

A link to the September 11 attacks surfaced after Ramzi bin al-Shibh was captured on September 11, 2002. In his 2005 hearing, Mohamedou Ould Slahi recalled that bin al-Shibh had stayed at his home in Germany in October 1999 and later identified him as someone who had advised him to go to Afghanistan for training. The connection changed how Slahi’s past associations could be interpreted, though an allegation arising from interrogation was not the same as proof that he had planned or aided the attacks.

The government’s position in court was narrower than some public descriptions suggested. When Slahi’s habeas petition came before a federal court in 2009, the government did not argue that he was a major al-Qaeda figure or that he had taken part in al-Qaeda plans or attacks. It argued that he had belonged to al-Qaeda because he had sworn allegiance, associated with members, hosted leaders, and referred aspiring jihadists to an operative. Judge James Robertson granted the petition and ordered his release. The government later abandoned its initial argument that Slahi was detainable because he had aided the September 11 attacks, acknowledging that he probably did not know about them.

The public argument did not immediately reflect those distinctions. A 2010 New York Daily News editorial described Slahi as a leading recruiter for the attacks and urged the administration to appeal the release order, despite the editorial board’s lack of access to the court order and proceedings. The declassified, redacted order disclosed the government’s abandoned theory and its acknowledgment about Slahi’s likely lack of knowledge. The contrast exposes how a powerful accusation could circulate publicly even as the legal record became more qualified.

The government did appeal. In the wider Guantánamo habeas litigation, it had persuaded the D.C. Circuit to adopt a looser standard for deciding whether a detainee was part of al-Qaeda. On appeal, the court reversed Robertson’s order and remanded Slahi’s case for rehearing under that standard. It emphasized that the government had not criminally indicted him for material support of terrorism and was not seeking to detain him on the basis that he aided the September 11 attacks. The remaining dispute centered on whether his earlier oath and sporadic connections meant he was still part of al-Qaeda when captured.

Secrecy, Accountability, and the Record

The operation depended not only on movement between detention sites but also on keeping that movement and its consequences from view. In early 2002, even Mohamedou Ould Slahi’s family did not know he was in Jordan. The account describes Mauritania as a cooperating but politically vulnerable partner: the country’s president faced international criticism over human rights and domestic criticism over cooperation with United States counterterrorism policy. A return to Mauritania after secret transfer to Jordan, Slahi argues, could have exposed the absence of extradition proceedings and the months of interrogation abroad.

The memoir also places limits on what can be known from a censored record. Its editor describes the annotations as an effort to interpret blacked-out passages through context and public information, not to reconstruct the original text or reveal classified material. That distinction matters to the history of the operation: the record documents transfers, interrogation policies, court arguments, and official acknowledgments, while some details remain obscured. Slahi’s case thus shows both the reach of secret detention and the difficulty of establishing a complete account when the institutions responsible for the operation also control access to its evidence.