At 10 PM on June 25, 1996, a gigantic explosion struck the Khobar Towers housing compound for the U.S. Air Force in Dhahran, Saudi Arabia . A tanker truck filled with several tons of TNT detonated on a nearby parking lot, killing 19 U.S. soldiers and injuring more than 200 people . The attack, the largest on a U.S. target since the 1983 Marine barracks bombing in Lebanon, prompted three official inquiries in the United States, as well as the relocation of most U.S. military personnel in Saudi Arabia from the Eastern Province to Prince Sultan Airbase outside Riyadh.
Despite its scale and repercussions, the Khobar bombing continues to be the subject of considerable speculation, not least concerning the identities of the perpetrators. In 2001, a U.S. court formally indicted a group of Saudi Shi`a allegedly linked to a militant group called Saudi Hizb Allah . In 2007, William Perry, secretary of defense at the time of the bombing, stated that he believed al-Qa`ida was responsible . The then FBI director, Louis Freeh, claimed on the other hand that Iran had ordered the attack . Perhaps reflecting its bipartisan mandate, the 9/11 Report assigned blame to all of the above, by stating that “the operation was carried out principally, perhaps exclusively, by Saudi Hezbollah, an organization that had received support from the government of Iran. While the evidence of Iranian involvement is strong, there are also signs that al-Qaida played some role, as yet unknown” .
The issue of Iranian involvement is shrouded in so much secrecy and high level politics that any assessment based on open sources remains impossible. The question of al-Qa`ida’s involvement, on the other hand, can now be addressed because vast amounts of new information about both al-Qa`ida and Saudi jihadism in the 1990s have emerged in the past few years. This article will examine the hypothesis that al-Qa`ida alone was behind Khobar as well as the theory that Usama bin Ladin collaborated with Tehran.
Assessing al-Qa`ida’s Role
The principal reason to suspect al-Qa`ida’s involvement is the fact that Usama bin Ladin had a motive to attack. Since late 1990, Bin Ladin had expressed deep dissatisfaction with the U.S. military presence in his native Saudi Arabia, a presence he considered a violation of the sanctity of the “Land of the Two Holy Places.” In August 1996, he declared war on U.S. troops in the Arabian Peninsula. Although this declaration postdates the Khobar bombing, Bin Ladin had declared his readiness to attack U.S. troops several years earlier in informal settings . Moreover, Bin Ladin applauded the Khobar operation in a number of statements and interviews after the attack .
Many would also argue that Bin Ladin also had the operational capability. Al-Qa`ida-linked militants undertook several military operations overseas in the early 1990s, from an alleged assassination attempt on the former king of Afghanistan in Rome in November 1991, to the hotel bombings in the Yemeni port of Aden in December 1992, to guerrilla warfare in Somalia in 1993. There is also evidence that Bin Ladin sought to operate in Saudi Arabia from approximately 1994 onward. In mid-1994, Saudi authorities allegedly intercepted a shipment of explosives sent by al-Qa`ida from Sudan to Saudi Arabia . According to a declassified Iraqi document, Bin Ladin met with an Iraqi government representative in Khartoum in early 1995 and discussed “carrying out joint operations against foreign forces” in Saudi Arabia . The Yemeni jihadist Nasir al-Bahri has also said that Bin Ladin “opened branches of the al-Qa`ida organization in Saudi Arabia” in 1996 .
The third reason to suspect al-Qa`ida involvement is that prior to the Khobar bombing Saudi Arabia experienced two violent attacks by Saudi Arab Afghans . The first was the so-called al-Hudhayf incident in November 1994, in which Abdallah al-Hudhayf threw acid in the face of a police officer to avenge the arrest of the leaders of the moderate Islamist opposition two months earlier . The second attack was the November 1995 car bombing of the U.S. training mission to the Saudi National Guard in central Riyadh, in which five Americans and two Indians were killed . In their televised April 1995 confessions, the four alleged perpetrators, three of whom were Arab Afghans, said they were influenced by Usama bin Ladin, Abu Muhammad al-Maqdisi and Saad al-Faqih . Although the Riyadh attack was initiated “from below” and not orchestrated by Bin Ladin himself, it showed that Sunni militants were able and willing to use car bombings against U.S. targets in Saudi Arabia .
Finally, a specific piece of intelligence would seem to link Bin Ladin to Khobar. A retired CIA official has said that two days after the bombing, the National Security Agency intercepted phone calls from al-Qa`ida second-in-command Ayman al-Zawahiri and Ashra Hadi (head of Palestinian Islamic Jihad) allegedly congratulating Bin Ladin on the Khobar attack .
On closer inspection, however, these four arguments do not hold scrutiny. First, Bin Ladin’s statements on Khobar amount to endorsements, not claims of responsibility. It is entirely natural that Bin Ladin, when prompted by a journalist, would speak positively about an attack on a U.S. military target in Saudi Arabia. Second, the operational capacity of Bin Ladin’s network in Saudi Arabia in the mid-1990s was not as high as is often assumed. Bin Ladin’s exile in Sudan and association with revolutionary-minded Egyptian militants had weakened his links to the Saudi Islamist scene, and many of his potential collaborators were imprisoned after the 1995 Riyadh bombing . Third, the Khobar attack differed considerably from any operation undertaken by Sunni Islamists in Saudi Arabia both before and after 1996. The Khobar bomb contained between 20 and 100 times more explosives than the November 1995 Riyadh bomb. The expertise for such an operation does not seem to have existed in the Saudi jihadist community in the 1990s. Fourth, the report of the alleged congratulatory calls, apart from being uncorroborated by other sources, does not constitute evidence of direct responsibility. Bin Ladin himself did not initiate the calls, and presumably he did not explicitly admit responsibility in his response, as this would also have been reported.
More importantly, anyone arguing in favor of the al-Qa`ida hypothesis would have to explain two spectacular gaps in the record of evidence on Khobar. The first gap is the absence of any forensic or other direct evidence linking al-Qa`ida to the operation. This absence is all the more glaring when compared to the wealth of publicly available evidence on other al-Qa`ida operations and on other violent incidents, large and small, involving Sunni militants in the Saudi kingdom. Although secret evidence may exist, it is doubtful that it would be in large quantities. A former U.S. intelligence official has noted that in the course of reviewing the bulk of the evidence on the Khobar attack during 1996-1997, he never saw any reliable evidence of al-Qa`ida involvement .
The second gap is the silence on Khobar in the jihadist literature. The Saudi jihadist literature treats Khobar quite differently from other incidents in the kingdom in the 1990s, such as the Riyadh bombing, the al-Hudhayf affair or the 1998 Hijaz missile plot. While Abdallah al-Hudhayf and the Riyadh bombers are hailed as martyrs and the Hijaz missile plotters proudly named, no reference has ever been made to the identities of the Khobar bombers . Moreover, while several al-Qa`ida in the Arabian Peninsula militants have highlighted their links to the Riyadh bombers, no one has claimed a connection to the Khobar attackers. On the contrary, al-Qa`ida representative Yusuf al-`Uyayri later blasted Saudi authorities for innocently arresting and torturing him in the wake of the Khobar attack before “God allowed for the real perpetrator to be discovered” . Al-`Uyayri’s assessment is particularly important and credible because he grew up in Dammam and knew the jihadist community in the Eastern Province well.
In other words, it seems unlikely that Bin Ladin orchestrated the Khobar bombing. Did al-Qa`ida play an indirect and low-profile role in the attack?
Another hypothesis that enjoys support in certain U.S. government and intelligence circles is that al-Qa`ida secretly collaborated with Shi`a militants in an Iran-sponsored attack on Khobar. The 9/11 Commission, for example, noted that “we have seen strong but indirect evidence that his organization did in fact play some as yet unknown role in the Khobar attack” . This hypothesis is part of a broader theory about a secret alliance between Iran and al-Qa`ida dating back to the early 1990s and facilitated by the legendary Hizb Allah operative Imad Mughniyyeh .
The nature and full scale of the alleged evidence for this theory is difficult to assess because it has remained classified to this day. The principal open source information pointing to the existence of an Iran-al-Qa`ida alliance is the testimony of former al-Qa`ida member Jamal al-Fadl in the so-called Embassy Bombings Trial in 2001. Al-Fadl said that around 1993 Abu Hajir al-Iraqi, a prominent al-Qa`ida ideologue, advocated cooperation between Sunnis and Shi`a in the fight against the United States . Al-Fadl also allegedly witnessed a meeting between al-Qa`ida leaders and an Iranian representative in Khartoum . Al-Fadl further said that a group of al-Qa`ida members, including top al-Qa`ida operative Sayf al-Adl, went to south Lebanon in the early 1990s to train with Hizb Allah . Some have interpreted Iran’s post-9/11 refusal to extradite top al-Qa`ida leaders (among whom Sayf al-Adl) as an indication of Tehran’s fear of revealing its long-standing connections with al-Qa`ida .
From an outside vantage point, it is not difficult to challenge this hypothesis. As interesting as al-Fadl’s account may be, it is not corroborated by any other publicly available sources and thus hinges on one testimony alone. Moreover, there may be many reasons behind Iran’s refusal to extradite al-Qa`ida leaders post-9/11. Needless to say, a number of al-Qa`ida associates have categorically denied the existence of a link between al-Qa`ida and Iran . Finally, this hypothesis still does not answer the question of the nature of al-Qa`ida’s alleged contribution to the Khobar operation. Until significant new evidence to the contrary is made public, this must be considered a conspiracy theory.
Of course, conspiracies do occur, and nothing is impossible in the murky world of terrorism and espionage. Nevertheless, in the case of the Khobar bombing, the straightforward explanation is both more plausible and supported by more evidence.
Both the U.S. and the Saudi investigations concluded that the operation was carried out by a cell affiliated with the radical Shi`a group Hizb Allah al-Hijaz (or Saudi Hizb Allah) . The pro-Khomeini Hizb Allah al-Hijaz had never accepted the deal struck in 1993 between the pro-Shirazi Shi`a opposition and the Saudi regime . No less anti-American than their Sunni Islamist counterparts, the radical Shi`a splinter group may have seen the Khobar attack as a way to demonstrate strength, protest against the 1993 peace deal and embarrass the Saudi regime. They may also have speculated that an attack on a U.S. target would not spark the same draconian retaliation as would an attack on a Saudi government target. The scale and professional execution of the attack was due to the instruction and logistical assistance provided by the Lebanese Hizb Allah. Whether or not there was official Iranian support is another issue which cannot be assessed in academia.
Al-Qaida’s involvement in the 1996 Khobar bombing, however, can be ruled out until substantial new evidence to the contrary emerges. Bin Ladin welcomed the operation, but he was probably not responsible. In fact, his strongest link to the bombing may have been the involvement of his family’s construction company, the Saudi Bin Ladin Group, in the rebuilding of the Khobar Towers site .
Dr. Thomas Hegghammer is a Postdoctoral Research Associate at Princeton University and a Research Fellow at the Norwegian Defense Research Establishment (FFI). He is the author of Jihad in Arabia (Cambridge University Press, forthcoming) and the co-author of Al-Qaida dans le texte (Paris: PUF, 2005). Dr. Hegghammer has published widely on militant Islamism and has conducted extensive fieldwork in Saudi Arabia and elsewhere. His current research focuses on jihadism in Saudi Arabia, radical Islamist ideology and the history of the Arab Afghans. Dr. Hegghammer is currently writing a book about the life and ideology of Abdullah Azzam.
 For detailed accounts of the Khobar bombing, see the three official inquiries: The Khobar Towers Bombing Incident (Washington, D.C.: House National Security Committee, August 14, 1996); Report to the President and Congress on the Protection of U.S. Forces Deployed Abroad (Washington, D.C.: U.S. Department of Defense, September 15, 1996) (the so-called “Downing Report”); and Independent Review of the Khobar Towers Bombing (Washington, D.C.: U.S. Air Force, October 31, 1996). See also Joshua Teitelbaum, Holier Than Thou (Washington, D.C.: WINEP, 2000), pp. 83-98; Anthony Cordesman, Islamic Extremism in Saudi Arabia and the Attack on al-Khobar (Washington, D.C.: CSIS, June 2001); and Ed Blanche, “Security and Stability in the Middle East–The Al-Khobar Factor,” Jane’s Intelligence Review 13:6 (2001).
 Estimates of the quantity of explosives used vary from ”3,000-8,000 pounds” (Downing Report) to ”20,000 pounds” (Air Force Report).
 U.S.A. v. Ahmed al-Mughassil et al., Eastern District of Virginia, 2001.
 “Perry: U.S. Eyed Iran Attack after Bombing,” UPI, June 6, 2007. On December 22, 2006, a U.S. federal court ruled that Iran was responsible for the bombing and ordered that the Iranian government pay $254 million to the families of the 19 U.S. citizens killed. See Carol D. Leonnig, “Iran Held Liable In Khobar Attack,” Washington Post, December 23, 2006.
 Louis Freeh, “Khobar Towers,” Wall Street Journal, June 23, 2006.
 The 9/11 Commission Report (New York: W. W. Norton & Co., 2004), p. 60.
 In a speech recorded in Saudi Arabia around 1991 and posted on the internet in 2006, Bin Ladin can be heard advocating resistance to the U.S. presence. See Muzaffir al-Ansari, “Bin ladin shaban…an’am wa akram,” Muntada al-Hisba, May 14, 2006. According to Jamal al-Fadl, Bin Ladin, Abu Hajir al-Iraqi and Saad al-Sharif declared in internal al-Qa`ida meetings around 1993 that it was necessary and legitimate to use force against U.S. troops in the Gulf and in Somalia. See U.S.A. v. UBL, Southern District of New York, 2001, p. 266ff.
 In early July 1996, Bin Ladin told the journalist Robert Fisk that “what happened in Riyadh and Khobar when 24 Americans were killed in two bombings is clear evidence of the huge anger of Saudi people against America. The Saudis now know their real enemy is America.” See Independent, July 10, 1996. Later that year, Bin Ladin expressed his “joy at the killing of the American Soldiers in Riyadh and Khobar,” which “are the sentiments of every Muslim.” See Nida’ul Islam no. 15, December 1996. In March 1997, Bin Ladin told CNN that he considered as “heroes” those men who “killed the American occupiers in Riyadh and al-Khobar.”
 “Overview of the Enemy—Staff Statement Number 15,” www.9-11commission.gov, April 16, 2004.
 Peter Bergen, “Enemy of Our Enemy,” New York Times, March 28, 2006.
 Al-Quds al-Arabi, March 20, 2005.
 According to the “Downing Report,” there had also been three minor isolated attacks on U.S. personnel during the Gulf War in 1991.
 “Statement 38,” Committee for the Defence of Legitimate Rights, 1995; Personal interview with Abdallah al-Utaybi, Riyadh, April 2004.
 Teitelbaum, Holier than Thou, pp. 73-82.
 “Four Saudis Held for Riyadh Blasts,” Arab News, April 23, 1996.
 The 9/11 Report concluded that “nothing proves that Bin Ladin ordered [the 1995 Riyadh] attack.” See 9/11 Report, p. 60. Saudi Interior Minister Prince Nayef ruled out al-Qa`ida involvement. See al-Siyasa, November 4, 1998. Bin Ladin’s former bodyguard Nasir al-Bahri denied such a connection. See al-Quds al-Arabi, March 31, 2005. Bin Ladin himself expressed regret at not having been involved. See his interview with CNN, March 1997.
 Simon Reeve, The New Jackals (London: A. Deutsch, 1999), p. 187; Lawrence Wright, “The Man behind Bin Laden,” New Yorker, September 16, 2002.
 Thomas Hegghammer, Violent Islamism in Saudi Arabia, 1979-2006: The Power and Perils of Pan-Islamic Nationalism, Ph.D. Thesis, Sciences-Po Paris, 2007, p. 343ff.
 Personal interview, Wayne White, February 2, 2008.
 See, for example, Abu Jandal al-Azdi, “Khuribat Amrika,” www.qa3edoon.com, 2003, p. 81.
 Sawt al-Jihad, no. 1 (2003), p. 17. In another text, al-`Uyayri criticized the government for its “premature” accusations against the people on the “list of 19” for the May 12, 2003 Riyadh bombings, saying “they did not issue verdicts against the rafida who blew up Khubar.” See “ghazwat al-hadi ‘ashar min rabi’ al-awwal: ‘amaliyyat sharq al-riyadh wa-harbuna ma’ amrika wa ‘umala’iha,” www.qa3edoon.com, September 3, 2003, p. 45.
 “Overview of the Enemy—Staff Statement Number 15,” 9/11 Commission, April 16, 2004.
 See, for example, Dan Eggen, “9/11 Panel Links Al Qaeda, Iran,” Washington Post, June 26, 2004; Al Venter, “Bin Laden’s Tripartite Pact,” Jane’s Intelligence Review 10:11 (1998).
 U.S.A. v. UBL, p. 287.
 Ibid., p. 289.
 Ibid., pp. 290-291. The group that went to Lebanon allegedly included Abu Talha al-Sudani, Sayf al-Islam al-Masri, Abu Ja‘far al-Masri, Abu Salim al-Masri and Sayf al-Adl.
 Peter Finn and Susan Schmidt, “Iran, al Qaeda and Iraq,” Washington Post, September 6, 2003.
 In a 1994 interview, Ayman al-Zawahiri responded fiercely to allegations of such cooperation. See Ayman al-Zawahiri, “mawqifna min iran – al-radd ‘ala tuhmat al-ta’awun bayna al-haraka al-jihadiyya al-salafiyya wa iran al-rafidiyya,” al-Ansar, no. 91 (1994). Another witness in the Embassy Bombings Trial, L’Houssaine Kherchtou, rejected the possibility of links between al-Qa`ida and the Iranians; U.S.A. v. UBL, p. 1385.
 For summaries of the available evidence, see references in footnote 1. Further classified evidence allegedly supports this conclusion; former intelligence officials with the U.S. State Department’s Bureau of Intelligence and Research who followed the Khobar investigation saw convincing independent evidence linking Saudi Hizb Allah to the bombing. Personal interview, Wayne White, February 2, 2008.
 Gerd Nonneman, Anoushiravan Ehteshami, and Iris Glosemeyer, Terrorism, Gulf Security and Palestine: Key Issues for an EU-GCC Dialogue (Florence: European University Institute, 2002), pp. 30-31.
 Jane Mayer, “The House of Bin Laden,” New Yorker, November 5, 2001.