US intelligence hears of a bin Laden plot involving aircraft in the New York and Washington areas. [US Congress, 9/18/2002; New York Times, 9/18/2002] In December it will learn that al-Qaeda plans to hijack US aircraft are proceeding well and that two individuals have successfully evaded checkpoints in a dry run at a New York airport. [US Congress, 7/24/2003]
September 1998: Memo Outlines Al-Qaeda’s US Infrastructure
US intelligence authors a memorandum detailing al-Qaeda’s infrastructure in the US. This memo, which includes information regarding al-Qaeda’s use of fronts for terrorist activities [US Congress, 9/18/2002] , is provided to senior US officials. [US Congress, 7/24/2003, pp. 51 
]
Shortly After September 16, 1998: Captured Al-Qaeda Leader Is Linked to Al-Qaeda Hamburg Cell Member Zammar
The arrest of al-Qaeda leader Mamdouh Mahmud Salim (a.k.a. Abu Hajer) points US and German investigators to Mohammed Haydar Zammar, a member of the al-Qaeda cell in Hamburg, Germany, with a few of the future 9/11 hijackers. Salim is arrested on September 16, 1998, in Munich, Germany (see September 16, 1998). He is believed to be al-Qaeda’s financial chief, and is one of al-Qaeda’s founding members (see August 11-20, 1988). After Salim’s arrest, both German and US intelligence investigate his contacts in Germany and discover a link to Zammar. Zammar is already being investigated and monitored by the Office for the Protection of the Constitution (BfV), Germany’s domestic intelligence service (see March 1997-Early 2000). [Der Spiegel (Hamburg), 12/12/2005] Presumably, the link between Zammar and Salim should increase the urgency of the German investigation. It is unknown when US intelligence begins monitoring Zammar, but the US will discover important links between Zammar and al-Qaeda in the summer of 1999 (see Summer 1999). US and German investigators also discover a link between Salim and Mamoun Darkazanli, a Hamburg associate of Zammar’s, and they monitor him as well (see Late 1998).
Late 1998: Moles within Al-Qaeda Lead to Arrests of 20 of Bin Laden’s Closest Associates
Journalist Simon Reeve will write in the 1999 book The New Jackals that shortly after the African embassy bombings, “With the help of one, possibly two, medium-level moles within [al-Qaeda], Americans arrested and questioned 20 of bin Laden’s closest associates and began inquiries in 28 countries.” Reeve does not say how he knows this, but his book is heavily sourced by interviews with US intelligence officials. The notion that the US had moles within al-Qaeda runs counter to the usual official US position after 9/11 that al-Qaeda was nearly impenetrable. [Reeve, 1999, pp. 204] Top bin Laden associates arrested during this time include: 
Mamdouh Mahmud Salim (see September 16, 1998); Khalid al-Fawwaz, Ibrahim Eidarous, and Adel Abdel Bary (see Early 1994-September 23, 1998); Ihab Saqr, Essam Marzouk, and Ahmad Salama Mabruk (see Late August 1998); Ali Mohamed (see September 10, 1998); and Wadih El-Hage (see September 15, 1998).
Summer 1999: US Intelligence Links Hamber Cell Member Zammar to Senior Bin Laden Operatives, Fails to Share Information with Germany
Around this time, US intelligence notes that a man in Hamburg, Germany, named Mohammed Haydar Zammar is in direct contact with one of bin Laden’s senior operational coordinators. Zammar is an al-Qaeda recruiter with links to 9/11 hijacker Mohamed Atta and the rest of the Hamburg terror cell. The US had noted Zammar’s terror links on “numerous occasions” before 9/11. [US Congress, 7/24/2003 ] However, apparently the US does not share their information on Zammar with German intelligence. Instead, the Germans are given evidence from Turkey that Zammar is running a travel agency as a terror front in Hamburg. In 1998, they got information from Italy confirming he is an Islamic militant (see October 2, 1998). However, his behavior is so suspicious that they have already started monitoring him closely (see 1996). [US Congress, 7/24/2003 ; Stern, 8/13/2003] Ironically, also in 1999, German intelligence gives its information on Zammar to the CIA (see 1999).
Shortly Before December 29, 1999: NSA Monitors 9/11 Hijackers Talking to Each Other about Upcoming Al-Qaeda Summit
The NSA has been monitoring a telephone in an al-Qaeda communications hub in Yemen (see Late August 1998 and Late 1998-Early 2002). According to Vanity Fair, “Amid the storm of pre-millennial ‘chatter,’ the [NSA] intercepted communications among three Arabic men, each of whom bore some connection to the East Africa bombings (see 10:35-10:39 a.m., August 7, 1998) and to al-Qaeda.” The men are hijackers Khalid Almihdhar, Nawaf Alhazmi, and Salem Alhazmi. [Vanity Fair, 11/2004] Apparently, the NSA listens in on a phone call between al-Qaeda figure Khallad bin Attash and hijacker Khalid Almihdhar, who is staying at the hub. Attash mentions Almihdhar’s full name, as well as the first names of hijackers Nawaf Alhazmi and Salem Alhazmi. He says he wants the three of them to come to an important al-Qaeda summit in Malaysia in January 2000 (see January 5-8, 2000). The NSA has already heard the names of the three hijackers mentioned repeatedly in 1999 while monitoring the Yemen hub (see Early 1999). Apparently, US intelligence does not yet know bin Attash’s full name or role in al-Qaeda and won’t figure it out until late 2000 (see Early December 2000). [Wright, 2006, pp. 310] At the same time, US officials in Pakistan intercept Nawaf Alhazmi in Karachi calling Almihdhar at the Yemen hub. They learn Nawaf is planning a trip to Malaysia on January 4, 2000. The NSA is also monitoring Nawaf calling his brother Salem (the location of Salem at this time has not been revealed). [US Congress, 7/24/2003, pp. 143-144 ; Asia Times, 3/19/2004] The NSA will share details of these calls with the CIA and other agencies on December 29, 1999 (see December 29, 1999) and the CIA will eventually track Almihdhar to the Malaysia summit (see January 2-5, 2000).
January 30-31, 2000: UAE Wants to Arrest 9/11 Hijacker Jarrah; US Says No and Promises to Track Him
The UAE wants to arrest future 9/11 hijacker Ziad Jarrah, but US officials say they will track him instead, according to United Arab Emirates (UAE) officials. It is unknown if the US officials actually do so. On January 30, 2000, Jarrah is stopped and questioned as he is transiting through the airport in Dubai, UAE. Officials at the airport have agreed to help the CIA by monitoring or questioning suspicious militants passing through there (see 1999).
Conflicting Accounts – There will be some controversy about what happens next. According to a January 2002 FBI memo, “UAE authorities stopped Jarrah, apparently, because he had the Koran superimposed on part of his passport and he was carrying other religious materials.” [Chicago Tribune, 2/24/2004] But according to UAE officials, Jarrah is stopped because he is on a US watch list (see January 30, 2000).
Jarrah’s Admissions – Regardless of why he is stopped, Jarrah is questioned and he all but admits he has just been to training camps in Afghanistan. A UAE official will later say, “When we questioned him, he said he spent two months and five days in Pakistan, some part of it in Afghanistan.” Furthermore, Jarrah says that he is going to the US to preach Islam and learn to fly airplanes.
UAE Officials Want to Arrest Him, but US Says No – While Jarrah is being held at the airport, UAE officials contact US officials and ask what they should do with him. (Note that there is some controversy about this as well, but FBI and German documents indicate the US is contacted while Jarrah is still being held (see January 30, 2000).) A UAE official will later say: “What happened was we called the Americans. We said: ‘We have this guy. What should we do with him?‘… [T]heir answer was, ‘Let him go, we’ll track him.’ We were going to make him stay. They told us to let him go. We weren’t feeling very happy in letting him go.” [Chicago Tribune, 2/24/2004; McDermott, 2005, pp. 186-187, 294-295] According to another account, UAE officials have a discussion with officials at the US embassy in Dubai on what to do with Jarrah. After some discussion, they conclude they do not actually have any charge to arrest him with, so it is decided to let him go. [Chicago Tribune, 9/28/2005]
UAE Officials Track Him to Hamburg; They Notify US Intelligence – After several hours of questioning, Jarrah is let go. He is allowed to board a flight for Amsterdam, Netherlands, but the flight does not leave until the next day, giving officials more time to prepare to track him if they want to. UAE officials are aware that after Jarrah arrives in Amsterdam, he changes planes for Hamburg, Germany. A UAE official will later say, “Where he went from there, we don’t know.” In fact, Jarrah lives in Hamburg and is part of the al-Qaeda cell there with fellow 9/11 hijacker Mohamed Atta and others. According to the FBI memo, this information about Jarrah’s detention and questioning “was reported to the US government.” UAE officials are cautious about mentioning which part of the US government is informed, but the implication is that it is the CIA. [Associated Press, 12/14/2001; Chicago Tribune, 2/24/2004; McDermott, 2005, pp. 186-187] However, it is unknown if US intelligence does track Jarrah.
Late Summer 2000: Informant Says Al-Qaeda to Attack US Warship
According to PBS, an Egyptian informant warns US intelligence that al-Qaeda will attack an American warship. [PBS, 10/3/2002] The FBI also notices increased telephone activity by al-Qaeda in Yemen around the same time (see August-Early October 2000). The USS Cole is attacked in the autumn of this year (see October 12, 2000).
Late 2000-September 10, 2001: US Intelligence Makes No Strategic Assessment about Islamic Militant Threat
The US intelligence community considers creating a strategic analysis about terrorism, but none is done before 9/11. The last National Intelligence Estimate (NIE) on terrorism was released in 1997 (see 1997). The 9/11 Commission will later say that assessments such as NIEs can “provoke widespread thought and debate [and ] have a major impact on their recipients, often in a wider circle of decision makers.” By late 2000, CIA Director George Tenet recognizes the lack of any recent strategic analysis about al-Qaeda or Islamic militancy in general. He appoints a senior manager, who briefs him in March 2001 about “creating a strategic assessment capability.” The CIA’s Counterterrorist Center (CTC) establishes a new strategic assessments branch in July 2001 and about ten analysts are slated to work for it. But it takes time to hire the new staff and the first head of this branch reports for work just one day before 9/11. [9/11 Commission, 7/24/2004, pp. 342-343] Not only is there no NIE or any other sweeping strategic assessment on al-Qaeda between 1997 and 9/11, but one still will not be completed five years after 9/11. Apparently the US military opposes such an assessment for fear it would reduce the military’s role in counterterrorism efforts (see September 12, 2006).
December 18, 2000: CIA Director Warns Clinton of Increased Risk that Al-Qaeda Could Attack in Coming Weeks
In a memo to President Clinton that is also widely distributed in the US intelligence community, CIA Director George Tenet warns: “The next several weeks will bring an increased risk of attacks on our country’s interests from one or more Middle Eastern terrorist groups… The volume of credible threat reporting has grown significantly in the past few months, particularly concerning plans by Osama bin Laden’s organization for new attacks in Europe and the Middle East.… Our most credible information on bin Laden activity suggests his organization is looking at US facilities in the Middle East, especially the Arabian peninsula, in Turkey and Western Europe. Bin Laden’s network is global however and capable of attacks in other regions, including the United States.” [Tenet, 2007, pp. 128-129] Just one day later, Clinton will brief incoming President Bush on the al-Qaeda threat (see December 19, 2000).
