The 9/11 Commission will later call Mohamedou Ould Slahi “a significant al-Qaeda operative who, even [in late 1999], was well known to US and German intelligence, though neither government apparently knew he was operating in Germany.” [9/11 Commission, 7/24/2004, pp. 165]
Thinks He Was Monitored – However, while in US custody after 9/11, Slahi will allege that a phone call he received in January 1999 from his cousin Mahfouz Walad Al-Walid, a top al-Qaeda leader living in Afghanistan, was monitored. Slahi will say, “I later learned that my cousin was using Osama bin Laden’s satellite phone that was intercepted.” Another mutual cousin was arrested that month and Slahi says, “I wasn’t captured, but I am sure I was followed by the German police [and/or] German intelligence.” He claims the imam at his mosque told him that German officials had come to ask questions about him and was told Slahi had ties with terrorists. [US Department of Defense, 4/20/2006, pp. 184-216] In 2000, the New York Times will report that German authorities became interested in Slahi “shortly after the bombings of American Embassies in East Africa in 1998. The German authorities learned that [he] might have ties to Islamic extremists in Europe.” [New York Times, 1/29/2000]
Links to 9/11 Hijackers – After Hamburg al-Qaeda cell member Ramzi bin al-Shibh is captured in 2002, he will allegedly claim that Slahi was the one who originally recruited 9/11 hijackers Marwan Alshehhi and Ziad Jarrah. [Agence France-Presse, 10/26/2002] After 9/11, another prisoner in US custody will say that Slahi and bin al-Shibh met in Frankfurt in 1999 through an acquaintance. This acquaintance will go further and will claim Slahi knew bin al-Shibh and Jarrah since at least 1998 and that Slahi later lived with them in Hamburg. [9/11 Commission, 7/24/2004, pp. 496] In October 1999, bin al-Shibh and Alshehhi call Slahi, and he invites them to come to where he lives in Duisburg, Germany. Bin al-Shibh, Alshehhi, and Ziad Jarrah soon go visit him there. Karim Mehdi, an apparent leader of the al-Qaeda Ruhr Valley cell who will later be sentenced to nine years in prison for a post-9/11 plot, is also at this meeting. Bin al-Shibh, Alsehhi, and Jarrah follow Slahi’s advice to go to Afghanistan instead of Chechnya, and he gives them instructions on how to meet up with al-Qaeda operatives there. [9/11 Commission, 7/24/2004, pp. 165; Deutsche Presse-Agentur (Hamburg), 8/3/2005; Associated Press, 10/26/2006] US investigators later believe Slahi worked closely on al-Qaeda matters with bin al-Shibh and instructed another militant to go to the US and to take part in the 9/11 plot. Additionally, he is believed to have a key role in Ahmed Ressam’s millennium plot (see December 15-31, 1999). [Los Angeles Times, 4/24/2006]
No Action – German authorities are monitoring and wiretapping the phones at bin al-Shibh’s apartment throughout 1999 (see November 1, 1998-February 2001 and 2000), but they apparently do not connect Slahi to the Hamburg militants or do not act on that connection. The Germans will apparently miss another chance to learn of his ties to the Hamburg cell in April 2000, when Slahi is arrested for three weeks in Germany and then let go (see January-April 2000). [US Department of Defense, 4/20/2006, pp. 184-216] Note that the testimonies of detainees such as Slahi and bin al-Shibh are suspect due to widespread allegations that they were tortured into confessions (for instance, see September 27, 2001).
December 15-31, 1999: US Intelligence Launches Worldwide Effort to Thwart Millennium Attack Plots
In the wake of the arrest of Ahmed Ressam (see December 14, 1999), FBI investigators work frantically to uncover more millennium plots before the end of the year. US authorities also make a number of arrests. 
A telephone number found in Ressam’s pocket leads to Abdel Ghani Meskini, an Algerian living in New York City who had gone to Seattle to meet Ressam. Meskini is monitored and arrested in New York on December 30. One of Ressam’s credit cards leads to the arrest of Mokhtar Haouari, an Algerian living in Montreal, Canada. Meskini later cooperates with US investigators and is never charged, while Haouari will be sentenced to 24 years in prison. [Time, 2/7/2000; CNN, 1/16/2002; Wright, 2006, pp. 298] Another Algerian associate of Ressam’s, Abdelmajid Dahoumane, escapes to Afghanistan, but will eventually be caught by the Algerian government and convicted in Algeria. [PBS Frontline, 10/25/2001] Investigators believe that Mohamedou Ould Slahi, an al-Qaeda operative whose cousin is a top al-Qaeda leader, went to Canada to give the go-ahead for Ressam’s attack. Slahi is arrested several times overseas, but never charged (see January-April 2000). [CNN, 3/6/2002] Khalid Deek, a US citizen, is arrested around this time for masterminding another al-Qaeda millennnium plot (see December 11, 1999). But counterterrorism expert Rita Katz will later say Deek was a suspected mastermind of Ressam’s Los Angeles airport plot, too. [Orange County Register, 9/12/2005] Deek’s name and phone number is found in Ressam’s telephone book. Ressam knew Deek from bin Laden training camps in Afghanistan. Both of them, like most of Ressam’s group, have links to the GIA, an Algerian militant group associated with al-Qaeda. [Newsweek (International), 3/13/2000]
Others escape the US after hearing media reports of Ressam’s arrest. However, enough people are caught to stop additional millennium attacks. Counterterrorism “tsar” Richard Clarke later says, “I think a lot of the FBI leadership for the first time realized that… there probably were al-Qaeda people in the United States. They realized that only after they looked at the results of the investigation of the millennium bombing plot.” [PBS Frontline, 10/3/2002] Yet Clinton’s National Security Adviser Sandy Berger later claims that the FBI will still repeatedly assure the Clinton White House until Clinton leaves office that al-Qaeda lacks the ability to launch a domestic strike (see 2000).
Early 2000-September 2001: Al-Qaeda Recruiter Said to Run Radical Militants Communications Network
Mohamedou Ould Slahi, who helped recruit three of the 9/11 hijackers and has been known to German and US intelligence for some time (see 1999), returns home to Mauritania in early 2000 and starts working at a series of internet cafes that appear to be cover for a radical militant communication network. Slahi is also thought to be involved in the Millennium Plot, is arrested and released twice before 9/11, and is questioned by the FBI and others about his knowledge of the Millennium Plot (see January-April 2000). After 9/11, Slahi will be investigated by an independent Swiss researcher called Guido Rudolphi, who runs an internet monitoring service. Rudolphi will find that Slahi runs a group of seemingly innocuous websites, but behind them there are guest books where visitors can leave messages. According to Rudolphi, this is the perfect communication tool for extremists, “[I]f you want to hide the content of the communication, you can put a message in the guest book. The owner of the guest book receives an e-mail, within seconds can look at the message, edit it, so it looks pretty normal, although the real content, which he has seen already, has disappeared, and may be harmful.” A dramatic increase in such traffic begins in May 2001, but then drops to an all-time low shortly before September 2001. By analysing the traffic, Rudolphi will find that the trail leads back to Duisburg, Germany, where Slahi studied at university. After 9/11, western intelligence agencies will come to the conclusion that Rudolphi’s research is well-founded and indicate that al-Qaeda had an operations center in Duisburg. [CNN, 3/6/2002]
January-April 2000: US and Germany Fail to Discover Militant’s Links to 9/11 Plot Despite Arrests
The US and Germany miss an opportunity to uncover the 9/11 plot through the arrest of Mohamedou Ould Slahi, an al-Qaeda operative tied to millennium attacks and the Hamburg al-Qaeda cell. Slahi lived in Duisburg, Germany for most of the 1990s and apparently US and German intelligence began monitoring him there around the start of 1999 due to his communications with his cousin, al-Qaeda leader Mahfouz Walad Al-Walid. In 1999 he had repeated contact with members of the Hamburg al-Qaeda cell and helped some of the 9/11 hijackers travel to Afghanistan. US investigators will later allege he also advised one militant to “travel to the United States to take part in the planned [9/11] attacks” (see 1999). In November 1999, Slahi moves to Canada and is seen with associates of Ahmed Ressam, who is planning to bomb the Los Angeles airport. US officials will later believe that Slahi went to Canada to activate Ressam’s cell. [Los Angeles Times, 4/24/2006] After Ressam is arrested in mid-December 1999 (see December 14, 1999), Slahi is monitored closely. He is arrested in Senegal after flying there in mid-January 2000. Transfered to his home country of Mauritania, he is interrogated by FBI officials. [New York Times, 1/29/2000; Agence France-Presse, 2/20/2000; Los Angeles Times, 4/24/2006] In early February 2000, Newsweek will report, “The key link in the chain connecting bin Laden to Ahmed Ressam—and an alleged New Year’s bomb plot in the United States—may be Mohamedou Ould Slahi.” [Newsweek, 2/7/2000] However, despite these suspicions, he is released later in February. He moves back to Germany, and is arrested and held there in April 2000 for three weeks, and then released again. He quickly returns to Mauritania. He will be arrested again shortly after 9/11. [Agence France-Presse, 2/20/2000; US Department of Defense, 4/20/2006, pp. 184-216] Despite all this interest in Slahi, his connections to the 9/11 plot and some of the 9/11 hijackers in Hamburg are apparently not made until after 9/11. He will later be sent to Guantanamo where he is reportedly subjected to harsh interrogation (see September 27, 2001).
March 16, 2000: Report: Intelligence Agencies Are Not Acting to Stop Bin Laden’s Businesses and Charities
Intelligence Newsletter reports that a number of Osama bin Laden-owed businesses in Sudan are still operating and still controlled by bin Laden. The report specifically mentions Wadi al-Aqiq, El-Hijra Construction and Development, Taba Investment Company, and the Al-Shamal Islamic Bank. Bin Laden’s control of all these businesses were revealed in detail to US intelligence by al-Qaeda informant Jamal al-Fadl several years earlier (see December 1996-January 1997). The report notes that both Mahfouz Walad Al-Walid and his cousin-in-law Mohamedou Ould Slahi, both known al-Qaeda leaders, were reportedly employed in recent years by the El-Hijra company. The report further notes that money for bin Laden “pours into accounts at branch offices of Al Taqwa [Bank] in Malta,” Switzerland, and the Bahamas. Businesses and charities supporting bin Laden “are thriving around the world without any real curb on their operations” because “some US and European agencies hunting him seem to lack zeal” in stopping him. “To be sure, if journalists can track down bin Laden’s friends without too much trouble it can be imagined that law enforcement and intelligence agencies have long found the same connections. Recent anti-terrorism history has shown that when the authorities really want to crack down on an organization they cut off its financial and logistic roots. So why are bin Laden’s backers prospering when the world’s most powerful anti-terrorist organizations are chasing him?” [Intelligence Newsletter, 3/16/2000]
September 27, 2001: Al-Qaeda Operative Arrested, Tortured in Ultra-Secret Facility
Mohamedou Ould Slahi, a Mauritanian businessman and alleged liaison between Islamic radicals in Hamburg and Osama bin Laden with foreknowledge of the 9/11 plot (see 1999 and January-April 2000), is arrested in Mauritania by secret police, his family says. By December, he will be in US custody. He will later be housed at a secret CIA facility within Camp Echo at the Guantanamo Bay Naval Station. [Washington Post, 12/17/2004] In 2007, it will be reported that one of Slahi’s prosecutors, Lt. Col. Stuart Couch, has refused to continue to prosecute Slahi after learning details of Slahi’s tortures at Guantanamo. [Wall Street Journal, 3/31/2007] The Nation will later report, “Aside from the beatings, waterboarding, stress positions, and sexual degradation that have been the norm at Guantanamo, Slahi was taunted with details of his mother’s incarceration and rape in an elaborate hoax by an officer who claimed to be representing the White House.” While Couch believes Slahi is a high-level al-Qaeda operative, he also believes the much of the evidence against him is not credible because of the methods used to obtain it. [Nation, 4/4/2007]
