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Al Qaeda 9/11 Conspiracy Essay

The 9/11 Truth Movement: The Top Conspiracy Theory, a Decade Later


Dave Thomas

Skeptical Inquirer Volume 35.4, July/August 2011

After ten years, the pesky 9/11 Truth movement has refined its arguments but still hasn’t proved the attacks were an inside job. Their key claims are refuted on multiple grounds.

The conspiracy theories started flying just days after the September 11, 2001, terrorist attacks on New York and Washington, DC. Over the decade since, several technically elaborate claims have been refined by the “9/11 Truth” movement. Do these intricate arguments—including the rapid collapses of the towers, alleged evidence of thermite usage at Ground Zero, and the collapse of World Trade Center (WTC) 7 (a forty-seven-story building damaged by the fall of WTC 1) “into its own footprint at freefall acceleration”—disprove the mainstream consensus that the September 11, 2001, attacks were the work of al-Qaeda terrorists using hijacked airplanes? In a word: No.

The Players

Dylan Avery and Jason Bermas, the creators of the low-budget documentary film Loose Change, did much to give the 9/11 Truth movement significant momentum in 2005 and in following years. The film, which has undergone several revisions, has been shown on many television stations but is primarily an Internet and DVD phenomenon. Its basic claims are that Flight 77 could not have accounted for the damage at the Pentagon, that the Twin Tower fires were insufficient to cause their collapse, and that cell phone calls from the hijacked airplanes would have been impossible at the time (Avery 2009).

David Ray Griffin is a theologian whose voluminous writings on 9/11 are frequently cited by other 9/11 theorists. NASA scientist Ryan Mackey has written a very thorough critique of Griffin’s claims (Mackey 2008).

Once known as Fleischmann and Pons’s competitor for “cold fusion” research in Utah, Steven Jones has written several 9/11 Truth articles. His work with others (including chemist Niels Harrit of Denmark) on detecting nanothermite in WTC dust is frequently cited as “peer-reviewed research” that proves “inside job” claims.

Physics teacher David Chandler has produced several papers and Internet videos contending that high school physics easily shows that the tower collapses could not have happened from gravity alone. He claims this proves that explosives must have been used.

In the past few years, architect Richard Gage’s group, Architects and Engineers for 9/11 Truth (AE911 Truth), has provided “Truthers” with the ability to claim that thousands of engineering and architecture professionals demand a new investigation into the cause of the attacks. Gage travels the world giving presentations, and his group puts on news conferences and mock debates several times a year (but most often around September 11, the anniversary of the attack) (Thomas 2009; Thomas 2010c).

Hollywood stars who have publicly supported 9/11 Truth claims include Rosie O’Donnell, Charlie Sheen, and Ed Asner. Sheen often talks 9/11 with radio host Alex Jones ( These celebrities frequently cite (and sometimes mangle) claims made by Truther proponents like Griffin and Gage. Former wrestler and Minnesota governor Jesse Ventura has done two 9/11 conspiracy shows on his TruTV series Conspiracy Theory (see “Dave Thomas vs. Jesse Ventura: The Skeptical Smackdown”).

The Claims

As with any well-developed pseudoscience, literally thousands of individual arguments can be advanced in support of the proposition that the United States secretly carried out the September 11 attacks. This report will examine the most enduring and oft cited of these claims: “free fall” of the towers, reports of thermite and molten steel, and WTC 7’s curious collapse. Some of the factions that have developed (such as the “no-planers”) will also be described briefly.

Claim One:
“The Twin Towers collapsed at free-fall accelerations through the path of greatest resistance.”

Perhaps the most bizarre aspect of September 11 was the rapid destruction of both 110-story Twin Towers: after the collapses began due to cascading structural failures at the airplane impact locations, each tower fell completely in just fifteen to twenty seconds. Mainstream scientific analyses, including years of work by the National Institute of Standards and Technology (NIST), generally looked at the cause of each collapse: the intense fires (started by jet fuel and fed by office contents and high winds) eventually caused floor trusses to sag, pulling the perimeter walls inward until they finally snapped. At this instant, the entire upper section of each tower fell the height of one floor, initiating an inevitable, progressive, and utterly catastrophic collapse of each of the structures.

While the mainstream explanation (dismissed as the “official story” by 9/11 Truthers) usually ends with the initiation of these unstoppable collapses, the 9/11 Truth movement’s attacks begin there. Gage of AE911 Truth says on that group’s website, “Destruction [of the Twin Towers] proceeds through the path of greatest resistance at nearly free-fall acceleration” (Gage 2011; emphasis added). Many 9/11 Truther pundits drop the “nearly” and say simply that the collapses were at free fall. Truthers then insist that free fall acceleration indicates a complete lack of resistance, proving that the structures were demolished with explosives. We are also told that the sheer mass of the towers, “80,000 tons of structural steel,” would simply resist collapse.

How could the buildings fall so quickly? It’s been explained very well in the technical literature by Northwestern’s Zdenek Bazant, PhD, and others (see, for example, Bazant 2008). I’ve developed a simpler physics model of the progressive collapses that agrees quite well with the main points of Bazant’s more rigorous results (Thomas 2010b). Here are some of my findings:

  • Each floor of the towers contained over two million kilograms of mass. The gravitational potential energy of a standing tower with twelve-foot floors extending upward 110 stories can be calculated straightforwardly; it comes to over 420 billion joules of energy, or the equivalent of 100 tons of TNT per tower. This energy, which was released completely during the collapses, is more than the energy of some of the smaller nuclear weapons in the U.S. arsenal, such as the W-48 (72 tons TNT) (Sublette 2006). This is where the energy required to break columns, pulverize concrete, and expel debris through windows came from. (Truthers often compare such expulsions of air and debris, visible several floors below the collapse fronts, to “squibs,” explosive devices often used in demolitions. However, they are readily explained by pressure changes as the towers, acting like a gigantic bicycle pump being compressed, collapsed.)
  • The Twin Towers used a “tube within a tube” architectural design, which provided considerable open office space in the interiors of the Towers. Much of the structural support was provided by a dense grouping of thick central core columns in the interior and the perimeter walls on the outside. When the towers began to collapse, large parts of the inner cores (called “the Spires” in 9/11 Truth circles) were actually left standing, briefly, before they, too, toppled over. The perimeter walls were largely forced to peel outward in large sections, producing the iconic images of Ground Zero with which we’re all familiar. Between the outer perimeter and the inner core, the weight of the upper sections plowed through one floor after another, breaking the floor connection brackets and support columns, pulverizing concrete decks, and gaining momentum and mass with each additional floor failure. Had the buildings been constructed differently (the Port Authority was allowed to circumvent some existing New York buildings requirements for the Towers), the collapses might not have even happened (Young 2007).
  • Even the 9/11 Truth movement’s most eminent physicists are confused about the basic principle of the difference between static and dynamic forces. A piece of paper, taped across a jar’s opening, will support a heavy coin such as a quarter indefinitely (static load). However, if the coin is dropped from just a few inches up, it will tear right through the paper (dynamic load). Given the information at hand—for example, the mass of the upper section of the north tower (fifty-eight million kilograms), the distance it fell (3.8 meters, about twelve feet), and the stiffness/rigidity of the lower structure itself, the dynamic force imparted on the lower section can be estimated as some thirty times the upper portion’s weight. This is many times the lower structure’s safety margin, which explains why it was quickly overwhelmed.
  • Once progressive collapse began, there were decreasing time intervals of free fall (between floors), punctuated by very brief, incredibly violent collisions—decelerations—of the upper mass, for each floor in turn. There was resistance at every step of the collapse, as the upper section collided with and incorporated each floor below. Conservation of momentum shows that the reductions in falling speed were slight as each floor was impacted, going as the ratio of floors before to floors after (e.g. 14/15, or about 94 percent, for the first impact). Accordingly, the upper section fell from rest to about 19 mph, was slowed down to 18 mph by the first impact, continued to fall until a speed of 26 mph was reached, was then slowed down to 24 mph by another impact, and so on. While the first plunge lasted about nine-tenths of a second, the upper section took only four-tenths of a second to fall through the next floor, three-tenths of a second for the next one, and so on until the bottom floors, which were crushed at a rate of just seven-hundredths of a second each, at speeds of over 100 mph. Yes, there was resistance at every step, as many tons of structural steel was demolished; yet the entire process, like an avalanche, lasted only fifteen to twenty seconds, about 50 to 100 percent longer than true “free fall” would have lasted.
  • Physics teacher David Chandler’s measurements of the first seconds of the collapse of the North Tower (WTC 1) showed that it fell with increasing speed but at only two-thirds of gravitational acceleration (g) (Chandler 2010). Chandler argues that this means the bottom section exerted a constant upward force of one-third of the upper section’s weight upon its mass, and he declares that this force should have been much larger, indicating that “some sort of controlled demolition was at work.”
  • Second, Chandler argues that being a Newtonian action/reaction pair, the impact force of the upper section on the lower section was only a third of the upper part’s weight. However, I’ve found that his estimate of the downward impact force was too low by a factor of one hundred. In addition, I found that the actual process—a series of twelve-foot free falls punctuated by violent and brief collisions with each floor—would have resulted in an average acceleration of precisely what Chandler measured for the start of the collapse of WTC 1, namely 2/3 g. (By the end of the collapse, my calculations indicate an average acceleration of only 1/3 g, but this can’t be measured in dust-obscured videos.)

Claim Two:
“Nano-thermite and military-grade explosives were found in dust from the towers. Tons of melted steel were found in tower debris.”

The thermite reaction is very hot, but it is also very slow compared to high explosives.

Real controlled demolitions commonly use explosives to topple large buildings. However, the hallmarks of actual demolitions (the characteristic “boom-boom-boom-boom” sounds and the flashes of high explosives) were completely absent in Manhattan on the morning of September 11, 2001. Many 9/11 Truth advocates, including architect Richard Gage, insist that high explosives must have been used to bring down the Twin Towers, as they say this is the only process that can possibly explain the “ejection of debris hundreds of feet from the towers.” However, they simultaneously insist that thermite or a derivative (thermate, nanothermite, etc.) was used instead, so as to topple the towers quietly. (This is but one of many instances in which 9/11 Truth claims flatly contradict each other.) Thermite itself fails as an explanation for the destruction of the Towers on many levels:

  • The thermite reaction, which takes place between iron oxide (rust) and powdered aluminum, is practical for welding train tracks in the field and for destroying engines of vehicles that must be left behind during combat operations. The self-sustaining reaction, once initiated with heat, produces significant volumes of molten iron, which can melt and cut iron structures beneath it. For thermite to melt through a normally vertical steel beam, however, special high-temperature containment must be added to prevent the molten iron from simply dropping straight down uselessly. The thermite reaction is very hot, but it is also very slow compared to high explosives. Thermite is simply not practical for carrying out a controlled demolition, and there is no documentation of it ever having been used for that purpose.
  • Jesse Ventura hired New Mexico Tech to show how nanothermite can slice through a large steel beam. The experiment was a total failure—even in the optimum (horizontal) configuration, the layer of nanothermite produced lots of flame and smoke but no actual damage to the massive I-beam tested. However, Ventura’s TruTV Conspiracy Theory show slyly passed it off as a rousing success (Thomas 2010a).
  • Niels Harrit and Steven Jones, along with several coauthors, published the “peer-reviewed” paper “Active Thermitic Material Discovered in Dust from the 9/11 World Trade Center Catastrophe” in the Bentham Open Chemical Physics Journal (Harrit 2009). This article does not make the case for thermite use on 9/11. The paper examined “distinctive red/gray chips” found in WTC dust (unfortunately, with no chain of custody for the dust), and these were claimed to be thermitic because of their composition (iron oxides and pure aluminum) and other chemical properties. However, the presence of rust and aluminum does not prove the use of thermite, because iron oxide and aluminum are found in many common items that existed in the towers. Furthermore, the authors admit that their “differential scanning calorimeter” measurements of the supposed thermitic material showed results at about 450 degrees C below the temperature at which normal thermite reacts (Fana 2006). Finally, the scan of the red side of the “thermitic material” of Harrit/Jones is a dead-on match to material Jones himself identified as “WTC Steel Primer Paint” in his Hard Evidence Down Under Tour in November of 2009 (“Sunstealer” 2011).
  • Harrit’s article describes the red portion of the chips as “unreacted thermitic material.” But while thermite may be slow, it does not stop its reaction once it has begun. Because thermite supplies its own oxygen (via iron oxides), it can even burn underwater. Suggesting that the samples show partially reacted thermite is preposterous. Claiming that thermite would explain molten pools of steel weeks and months after the attack is equally preposterous.
  • The article’s publication process was so politicized and bizarre that the editor-in-chief of the Bentham journal that featured Jones’s article, Marie-Paule Pileni, resigned in protest (Hoffman 2009).
  • Thermitic demolition should have created copious pools of melted steel at Ground Zero, but nothing remotely like this was ever found. Truthers say iron microspheres found in the rubble indicate thermite; since hot fires and spot-welding do produce very tiny spheres of iron, though, these “microspheres” are not unexpected. Pictures of cranes holding red-hot materials in the rubble are said to show molten steel. Had this been the case, however, the crane rigs would have immediately seized up (Blanchard 2006). No reports of “molten steel” in the tower basements have ever been credibly verified (Roberts 2008). Some Truthers claim that a few pieces of sulfidized “eutectic” steel found in the towers proves thermate (thermite with sulfur) usage, but this occurred because sulfur, released from burned drywall, corroded the steel as it stewed in the pile for weeks (Roberts 2008).

Claim Three:
“Tower 7, which wasn’t hit by a plane, collapsed neatly into its own footprint.”

Courtesy of the Prints and Photographs Division, Library of Congress

The enigma of WTC 7 is becoming increasingly popular in Truther circles. We’re told that it wasn’t hit by a plane and was subjected to just a few “small office fires.” Yet it collapsed anyway, late in the afternoon of September 11, “falling neatly into its own footprint at freefall acceleration, just like a normal controlled demolition.” In particular, Truthers point to a brief period of freefall (2.25 seconds) that was confirmed by NIST in its WTC 7 final report (Sunder 2008; NIST 2010) as proving that the building was purposely imploded. However, WTC 7, too, fails to prove 9/11 was an “inside job”:

  • What is often conveniently left out of the story are actual reports from NYFD firefighters at the scene, which describe huge, raging, unfought fires on many floors at once and visible deformations and creaking of the building prior to its collapse (Roberts 2008). Tower 7 was not hit by an airplane; however, it was struck by a 110-story flaming skyscraper, the North Tower. The fires raged for hours, and they eventually caused a critical column (#79) to fail because of thermal expansion; NIST determined that this column was crucial to the building and could even be considered a design flaw. Its failure would have collapsed the building even without the other structural damage from WTC 1’s collapse and the fires.
  • WTC 7’s brief 2.25 seconds of free fall is now the Truthers’ best “smoking gun.” The claim usually goes like this: “The fifty-eight perimeter columns would have resisted and slowed the collapse to much less than freefall. The ‘freefall’ of WTC 7, admitted to by NIST, proves it was controlled demolition.” The problem is that this is a straw man argument. NIST found the collapse occurred in three stages. The first stage, which lasted 1.75 seconds, is when the fifty-eight perimeter columns were buckled; during this interval, the rooftop actually fell only about seven feet. This is because the breaking of columns saps speed, indeed making the collapse slower than free fall. In the second stage, which lasted 2.25 seconds, the already-buckled columns provided negligible support, and the north face of the structure free-fell about eight stories. (Try taking a plastic drinking straw and buckling it by folding it over and then pushing down on the bent straw with your hand. The crimped straw provides almost no resistance to vertical forces, and neither did the buckled columns of WTC 7.) The third stage described by NIST, which lasted 1.4 seconds, was again less-than-free fall, as the structure fell another 130 feet as it impacted more non-buckled structures toward the bottom of the building (NIST 2010).
  • The other half of the equation is that WTC 7 resembles a “classic controlled demolition” because it supposedly “imploded, collapsing completely, and landed in its own footprint” (Gage 2011). In actuality, it twisted and tilted over to one side as it fell, and parts of the building severely damaged two neighboring buildings (the Verizon and Fiterman Hall structures). When challenged with the obvious fact that Tower 7 spilled far outside its footprint, however, Truthers will often change their tune and start saying that any resemblance to a natural collapse is part of the cover-up.

Factions within 9/11 Truth

Early on, it was mainly MIHOP (“Made it happen on purpose”) versus LIHOP (“Let it happen on purpose”). Nowadays most serious Truthers down-pedal the “no-planers,” who say no plane hit the Pentagon or even the Towers. There is considerable friction between some groups, with certain 9/11 Truth groups attacking others as “disinformation agents.” However, 9/11 Truth is mostly a big tent. Many “serious” groups such as AE911 Truth quietly champion “no-planers” such as former pilot Dwain Deets, engineer Anders Bjorkman, and Craig Ranke of Citizen Investigation Team (CIT) (Gage 2011). Gage formally withdrew his support of CIT in February 2011, even as his website touted 9/11 articles in Foreign Policy Journal, an online publication notorious for its frequent forays into Holocaust denial.


As Ted Goertzel pointed out in his recent Skeptical Inquirer article “The Conspiracy Meme: Why Conspiracy Theories Appeal and Persist,” “When an alleged fact is debunked, the conspiracy meme often just replaces it with another fact” (Goertzel 2011). In another ten years, will the 9/11 Truth movement have developed new arguments, or will it stick with the polished claims discussed here? Either way, it appears this American conspiracy theory classic is here to stay.


Avery, Dylan. 2009. Loose Change 9/11: An American Coup. Distributed by Microcinema International. Released September 22.

Bazant, Dzenek, J. Le, F.R. Greening, and D.B. Benson. 2008. What did and did not cause collapse of World Trade Center Twin Towers in New York? Journal of Engineering Mechanics ASCE 13(10): 892–906. Available online at

Blanchard, Brent 2006. A critical analysis of the collapse of WTC Towers 1, 2, and 7 from an explosives and conventional demolitions viewpoint. Journal of Debunking 911 Conspiracy Theories 1(2). Available online at

Chandler, David. 2010. Destruction of the World Trade Center North Tower and fundamental physics. Journal of 9/11 Studies 28 (February). Available online at

Fana, Run-Hua, Hong-Liang Lü, Kang-Ning Sun, et al. 2006. Kinetics of thermite reaction in Al-Fe2O3 system. Thermochimica Acta 440(2) (January 15): 129–31.

Gage, Richard. 2011. Architects and Engineers for 9/11 Truth. Available online at

Goertzel, Ted. 2011. The conspiracy meme: Why conspiracy theories appeal and persist. Skeptical Inquirer 35(1) (January/February): 28–37.

Harrit, Niels H., Jeffrey Farrer, Steven E. Jones, et al. 2009. Active thermitic material discovered in dust from the 9/11 World Trade Center catastrophe. Bentham Open Chemical Physics Journal 2: 7–31. Available online at

Hoffman, Thomas. 2009. Bentham editor resigns over Steven Jones’ paper. Danish Science News Service (April 28). Available online at­_artikel_om_911. (Translation available online at

Mackey, Ryan. 2008. On debunking 9/11 debunking: Examining Dr. David Ray Griffin’s latest criticism of the NIST World Trade Center investigation. Journal of Debunking 911 Conspiracy Theories 1(4). Available online at

NIST. 2010. Questions and answers about the NIST WTC 7 investigation (updated September 17). Available online at

Roberts, Mark. 2008. World Trade Center building 7 and the lies of the ‘9/11 Truth movement.’ Available online at

Sublette, Carey. 2006. Complete list of all U.S. nuclear weapons. Nuclear Weapon Archive Organization. Available online at

Sunder, Shyam, Richard G. Gann, William L. Grosshandler, et al. 2008. NIST Final Report on the Collapse of World Trade Center Building 7. Available online at

“Sunstealer.” 2011. The sad case of Niels Harrit. JREF forum. Available online at

Thomas, Dave. 2009. How I debated a 9/11 Truther and survived. Skeptical Briefs 19(4) (December). Available online at

———. 2010a: The video Jesse Ventura doesn’t want the world to see! NM Skeptic Blog (March 24). Available online at

———. 2010b. Institute of Theoretical and Experimental 9/11 Physics 9-11 ‘Truth’ resources. New Mexicans for Science and Reason (August). Available online at

———. 2010c. 9/11 truth: The Coast-to-Coast AM debate. Skeptical Briefs 20(4) (December).

Young, Jeffrey R. 2007. A Berkeley engineer searches for the truth about the Twin Towers’ collapse. Civil and Structural Engineers on WTC Collapse. Available online at

9/11 Internet Resources

The James Randi Educational Foundation (JREF) Forum, 9/11 Conspiracy Theory area.
If you need every single 9/11 Truth claim sliced and diced a 
thousand ways, this is your site.

Mark Roberts (“Gravy”)

Screw Loose Change blog

AE911Truth.Info (Joseph Noble)
“Answering the questions of Architects and Engineers for 9/11 Truth”

9/11 Myths: Reading between the Lies

Dave Thomas

Dave Thomas, a physicist and mathematician, is president of New Mexicans for Science and Reason and a fellow of the Committee for Skeptical Inquiry. He is currently a scientist/programmer at IRIS/PASSCAL in Socorro, New Mexico, and also teaches classes in physics, psychology, and critical thinking at New Mexico Tech.

This article is about 9/11 conspiracy theories. For historical discussion, see September 11 intelligence prior to the attacks. For the mainstream account, see September 11 attacks.

The 9/11 advance-knowledge conspiracy theories center on arguments that certain institutions or individuals other than the perpetrators had foreknowledge of the September 11 attacks in the United States in 2001.

Some of the primary concerns include whether the Bush administration or the United States Armed Forces had awareness of the planned attack methods, the precise volume of intelligence that American agencies had regarding al-Qaeda activities inside the United States, whether the put options placed on United Airlines and American Airlines and other trades indicate foreknowledge, and why the identities of the traders have never been made public.

Additional facets of the conspiracy theories include debate as to whether warnings received from foreign agencies were specific enough to have warranted preventative action, whether domestic intelligence about planned al-Qaeda attacks was thorough enough to have mandated intervention, the extent to which the alleged hijackers were under surveillance prior to the attacks, and whether Mossad or the PakistaniInter-Services Intelligence were aware of an imminent attack.

Using planes as missiles[edit]

Immediately following the attacks, President George W. Bush stated that: "Nobody in our government at least, and I don't think the prior government, could envisage flying air planes into buildings" and National Security AdvisorCondoleezza Rice claimed: "no-one could have predicted that they would try to use an airplane as a missile". An Air Force general called the attack: "something we had never seen before, something we had never even thought of."[1] A few days after the attacks, FBI Director Robert Mueller announced: "There were no warning signs that I'm aware of that would indicate this type of operation in the country."[2] However, Mueller noted that an FBI agent in Minneapolis said Moussaoui might be "that type of person that could fly something into the World Trade Center."[3] Mueller said this warning should have been followed more vigorously.

Some mainstream media reports have conflicted with these statements, claiming that the FBI, CIA and Executive Branch[4] knew of the threat of planes being used as missiles as early as 1995, following the foiling of the Bojinka Plot. In September 2002, one year after the 9/11 attacks, The Chicago Sun-Times reported that:

"The FBI had advance indications of plans to hijack U.S. airliners and use them as weapons, but neither acted on them nor distributed the intelligence to local police agencies. From the moment of the September 11 attacks, all high-ranking federal officials insisted that the terrorists’ method of operation surprised them. Many continue to stick to that story. Actually, elements of the suicide hijacking plan were known to the FBI as early as 1995 and, if coupled with current information, might have uncovered the plot."

The book The Terror Timeline includes numerous articles that are often cited to suggest that the method of flying planes into buildings was known by U.S. officials:[5]

  • In 1994, there were three examples of failed attempts to deliberately crash planes ito buildings, including one where a lone pilot crashed a small plane into the lawn of the White House.[6]
  • The Bojinka Plot was a foiled large-scale al-Qaeda terrorist attack to blow up eleven airliners and their passengers as they flew from Asia to America, due to take place in January 1995.
  • The 2000 edition of the FAA’s annual report on Criminal Acts Against Aviation said that although Osama bin Laden ‘is not known to have attacked civil aviation, he has both the motivation and the wherewithal to do so,’ adding, ‘Bin Laden’s anti-Western and anti-American attitudes make him and his followers a significant threat to civil aviation, particularly to U.S. civil aviation.’"
  • In April 2001, NORAD ran a war game in which the Pentagon was to become incapacitated; a NORAD planner proposed the simulated crash of a hijacked foreign commercial airliner into the Pentagon, but the Joints Chiefs of Staff rejected that scenario as "too unrealistic"[7][8]
  • In July 2001 at the G8 summit in Genoa, anti-aircraft missile batteries were installed following a report that terrorists would try to crash a plane to kill George Bush and other world leaders.[9]
  • On the morning of September 11, 2001, the National Reconnaissance Office, which is responsible for operating U.S. reconnaissance satellites, had scheduled an exercise simulating the crashing of an aircraft into their building, 4 miles (6 km) from Washington Dulles International Airport.[10]

A 2004 USA Today article, "NORAD had drills of jets as weapons," describes pre-9/11 NORAD drills that suggest they were prepared for such an attack as happened on 9/11:

"In the two years before the September 11 attacks, the North American Aerospace Defense Command conducted exercises simulating what the White House says was unimaginable at the time: hijacked airliners used as weapons to crash into targets and cause mass casualties. One of the imagined targets was the World Trade Center. In another exercise, jets performed a mock shootdown over the Atlantic Ocean of a jet supposedly laden with chemical poisons headed toward a target in the United States. In a third scenario, the target was the Pentagon — but that drill was not run after Defense officials said it was unrealistic."[7]

That NORAD was aware of the threat of terrorists hijacking commercial airliners within the United States, and using them as guided missiles, was flatly denied by the 9/11 Commission, which asserted several times in their report that "The threat of terrorists hijacking commercial airliners within the United States – and using them as guided missiles – was not recognized by NORAD before 9/11."

The Joint Inquiry of 2002 confirmed that the Intelligence Community had received at least twelve reports over a seven-year period suggesting that terrorists might use planes as weapons. After briefly discussing each of them, it says that "The CIA disseminated several of these reports to the FBI and to agencies responsible for preventive actions. They included the FAA... Despite these reports, the Intelligence Community did not produce any assessments of the likelihood that terrorists would use planes as weapons, and U.S. policymakers apparently remained unaware of this kind of potential threat."[11] Former National Security AdvisorSandy Berger testified to the Joint Inquiry:

"We heard of the idea of planes as weapons, but I don't recall being presented with any specific threat information about an attack of this nature, or highlighting this threat, or indicating it was more likely than any other"[12]


The Times reported on September 18 that investigations were under way into the unusually large numbers of shares in insurance companies and airlines sold off before the attack, in the UK, Italy, Germany, Japan, Switzerland, France and the US.[13][14] News accounts in the weeks that followed reported a notable pattern of trading in the options of United and American Airlines[15] as well as Morgan Stanley and other market activity.[16] An article published in The Journal of Business in 2006 provides statistical evidence of unusual put option market activity days before 9/11:

Examination of the option trading leading up to September 11 reveals that there was an unusually high level of put buying. This finding is consistent with informed investors having traded options before the attacks.[17]

In a statement to the 9/11 Commission in 2003, Mindy Kleinberg, of the 9/11 Family Steering Committee, said:

Never before on the Chicago Exchange were such large amounts of United and American Airlines options traded. These investors netted a profit of at least $5 million after the September 11 attacks. Interestingly, the names of the investors remain undisclosed and the $5 million remains unclaimed in the Chicago Exchange account.[18]

Regarding these trades, the 9/11 Commission found no malfeasance:

A single U.S.-based institutional investor with no conceivable ties to al-Qaeda purchased 95% of the UAL puts on September 6 as part of a trading strategy that also included buying 115,000 shares of American on September 10... much of the seemingly suspicious trading in American on September 10 was traced to a specific U.S.-based options trading newsletter, faxed to its subscribers on Sunday, September 9, that recommended these trades.[19]

WTC hard drive restoration operation[edit]

In December 2001 and early 2002, there was extensive media coverage of the efforts by the German data retrieval company Convar to reconstruct, using laser scanning technology, data from damaged hard drives recovered from the WTC as part of the investigation into a surge in financial transactions just before the two hijacked planes crashed into New York's World Trade Center.[20] The company's CEO, Peter Henschel, noting that the investigation was being conducted for a number of U.S. based clients cooperating with the FBI, said that there was suspicion that criminals had used inside knowledge about the attacks to make and authorize financial transactions during the chaos. According to Convar's data retrieval expert Richard Wagner, criminal transactions in excess of 100 million dollars could have been made in the hope that their trail would have disappeared as a result of the destruction of the WTC mainframe computers.[21][22] As reported by the Heute Journal, a news programme by the German ZDF TV channel, by March 2002 Convar had been able to restore several hundred hard drives from the WTC.[23]

However, the 9/11 Commission, in a memorandum entitled "FBI Briefing on Trading" dated October 18, 2003, said that when asked about the media coverage of the hard drive restoration operation, the "assembled [FBI] agents expressed no knowledge of the reported hard-drive recovery effort", further noting that one New York agent argued that it was "extremely unlikely that any hard-drives survived to the extent that they data [sic] be recovered."[24]

Later research[edit]

The papers of several finance researchers also suggest that some profited from foreknowledge of 9/11. In 2006, Allen Poteshman, a professor of Finance from the University of Illinois, published an analysis of the airline stock option trades preceding the attacks. This peer-reviewed study, published by the University of Chicago Press, came to the conclusion that an indicator of long put volume was "unusually high which is consistent with informed investors having traded in the option market in advance of the attacks".[25] In January 2010, a team of Swiss financial experts published evidence for at least thirteen informed trades in which the investors had apparent foreknowledge of the attacks.[26] Finally, in April 2010, an international team of experts showed that there was a significant abnormal increase in trading volume in the option market just before the 9/11 attacks in contrast to the absence of abnormal trading volume over periods long before the attacks, concluding that their findings were "consistent with insiders anticipating the 9-11 attacks".[27]

Intelligence warnings[edit]

The 9/11 Commission Report states that "the 9/11 attacks were a shock, but they should not have come as a surprise. Islamic extremists had given plenty of warnings that they meant to kill Americans indiscriminately and in large numbers."[28] The report continued:

During the spring and summer of 2001, U.S. intelligence agencies received a stream of warnings about an attack al-Qaeda planned, as one report puts it "something very, very, very big." Director of Central Intelligence George Tenet told us "the system was blinking red."[29]

The US administration, CIA and FBI received multiple prior warnings from foreign governments and intelligence services, including France, Germany, the UK, Israel, Jordan, Afghanistan, Egypt, Morocco and Russia.[5][30] The warnings varied in their level of detail, but all stated that they believed an al-Qaeda attack inside the United States was imminent. British Member of Parliament Michael Meacher cites these warnings, suggesting that some of them must have been deliberately ignored.[31] Some of these warnings include the following:

  • March 2001 – Italian intelligence warns of an al-Qaeda plot in the United States involving a massive strike involving aircraft, based on their wiretap of al-Qaeda cell in Milan.
  • July 2001 – Jordanian intelligence told US officials that al-Qaeda was planning an attack on American soil, and Egyptian intelligence warned the CIA that 20 al-Qaeda Jihadists were in the United States, and that four of them were receiving flight training.
  • August 2001 – The Israeli Mossad gives the CIA a list of 19 terrorists living in the US and says that they appear to be planning to carry out an attack in the near future.
  • August 2001 – The United Kingdom is warned three times of an imminent al-Qaeda attack in the United States, the third specifying multiple airplane hijackings. According to the Sunday Herald, the report is passed on to President Bush a short time later.
  • September 2001 – Egyptian intelligence warns American officials that al-Qaeda is in the advanced stages of executing a significant operation against an American target, probably within the US.

Able Danger[edit]

Main article: Able Danger

A classified military intelligence program known as "Able Danger" was created in October 1999 specifically targeting al-Qaeda. Lt. Col. Anthony Shaffer and Congressman Curt Weldon (R-PA) charged before the Senate Judiciary Committee that Able Danger had identified Mohamed Atta, and three of the other hijackers, prior to 9/11.

The existence of Able Danger, and its purported early identification of the 9/11 terrorists, was first disclosed publicly on June 19, 2005.[32] On June 27, 2005, Weldon stated to the House:

Mr. Speaker, I rise because information has come to my attention over the past several months that is very disturbing. I have learned that, in fact, one of our Federal agencies had, in fact, identified the major New York cell of Mohamed Atta prior to 9/11; and I have learned, Mr. Speaker, that in September 2000, that Federal agency actually was prepared to bring the FBI in and prepared to work with the FBI to take down the cell that Mohamed Atta was involved in in New York City, along with two of the other terrorists. I have also learned, Mr. Speaker, that when that recommendation was discussed within that Federal agency, the lawyers in the administration at that time said, you cannot pursue contact with the FBI against that cell. Mohamed Atta is in the U.S. on a green card, and we are fearful of the fallout from the Waco incident. So we did not allow that Federal agency to proceed.[33]

There is no mention of Able Danger in the 9/11 Commission Report. Two 9/11 Commission members, Timothy J. Roemer and John F. Lehman, both claimed not to have received any information on Able Danger.[34] Weldon alleged that intelligence concerning Able Danger was provided to the 9/11 Commission but was ignored.[35]

Following coverage in the national media of Weldon's claims in August 2005, Thomas Kean and Lee H. Hamilton, former Chair and Vice Chair of the 9/11 Commission, issued a statement[36] in which they stated the Commission had been aware of the Able Danger program, and requested and obtained information about it from the Department of Defense (DoD), but none of the information provided had indicated the program had identified Atta or other 9/11 hijackers.[37][38]

Curt Weldon issued a response to this statement clarifying the mission of Able Danger, expressing concern over the statements made by various members of the 9/11 Commission, and promising to push forward until it is understood why the DoD was unable to pass the information uncovered by Able Danger to the FBI, and why the 9/11 Commission failed to follow up on the information they were given on Able Danger.[39]

al-Qaeda investigations[edit]

See also: Responsibility for the September 11 attacks § Culpability

Numerous whistleblowers and officials have surfaced, claiming that there was a deliberate effort, from high-ranking officials, to prevent investigations into al-Qaeda.[citation needed]

In 2002, FBI agent Coleen Rowley wrote to FBI director Robert Mueller describing her experience working with Minneapolis FBI agents tracking suspected terrorist Zacarias Moussaoui prior to the attacks.[40] She describes how FBI HQ personnel in Washington, D.C. had mishandled and failed to take action on information provided by the Minneapolis Field Office, and had failed to issue a warrant to search Moussaui's computer despite having probable cause.[41][unreliable source?] Senator Chuck Grassley later wrote that “If the application for the FISA warrant had gone forward, agents would have found information in Moussaoui's belongings that linked him ... to a major financier of the hijacking plot". Rowley was credited as a whistleblower and jointly awarded the TIME Magazine "Person of the Year" for 2002. Her testimony to the 9/11 Commission was omitted from their final report.[citation needed]

FBI agent and al-Qaeda expert John P. O'Neill warned of an al-Qaeda threat to the United States in 2000. He retired from his position in mid-2001, citing repeated blocking of his investigations of al-Qaeda by FBI officials. After his retirement from the FBI, the World Trade Center hired him as its chief of security. He started work on August 23, 2001; 9/11 rescue workers found his body in a staircase inside the south tower rubble.[42]

Shortly after the attacks, David Schippers, the chief prosecutor for the impeachment of Bill Clinton, stated that the government had been warned in 1995 about a future attack on a government building and that later he was contacted by three FBI agents who mentioned uncovering a possible terrorist attack planned for lower Manhattan.[43] According to Schippers, as the agents informed their superiors, they were briefed not to pursue the issue and were threatened with prosecution. Schippers declared, "Five weeks before the September 11 tragedy, I did my best to get a hold of Attorney GeneralJohn Ashcroft with my concerns." According to Schippers, Ashcroft responded that the Justice Department does not start investigations at the top. Author William Norman Grigg agrees with Schippers in his article "Did We Know What Was Coming?" According to the article, three unnamed veteran federal law enforcement agents confirmed "the information provided to Schippers was widely known within the Bureau before September 11."[44]

According to Senator Bob Graham, who was chairman of the Senate Intelligence Committee from June 2001 through the buildup to the Iraq war, "Two of the September 11, 2001, hijackers had a support network in the United States that included agents of the Saudi government, and the Bush administration and FBI blocked a congressional investigation into that relationship," as reported by the Miami Herald. And in Graham's book, Intelligence Matters, he makes clear that some details of that financial support from Saudi Arabia were in the 27 pages of the congressional inquiry's final report that were blocked from release by the administration, despite the pleas of leaders of both parties on the House and Senate intelligence committees."[45] In March 2012 as part of a lawsuit by 9/11 victims families Graham and another former U.S. Senator Bob Kerrey said in affidavits that they were certain there were direct links between the Saudi government and the attacks.[46]

There have also been allegations that the hijackers' preparations may have been given assistance by U.S. intelligence. According to CBS News, "two of the Sept. 11 hijackers who lived in San Diego in 2000 rented a room from a man who reportedly worked as an undercover FBI informant... the FBI informant prayed with them and even helped one open a bank account."[47] Doubts have been raised about the speed with which the hijackers were identified, leading to suggestions that the FBI already had the names of the hijackers in advance. In his book Against All Enemies, Richard Clarke said that at 9:59 am on September 11, which is the time when WTC2 collapsed and 8 minutes before NORAD even knew Flight 93 had been hijacked, the FBI already had a list of the 19 alleged hijackers.[48] A former high-level intelligence official said that "Whatever trail was left was left deliberately—for the F.B.I. to chase."[49]

Foreign government foreknowledge[edit]

It has been suggested that some foreign governments and intelligence agencies may have had some foreknowledge of the attacks.


Sibel Edmonds, an FBI translator, was told by another translator that the FBI received information in April 2001, from a reliable Iranian intelligence asset, that Osama Bin Laden was planning attacks on 4–5 cities with planes, and that some of the plotters were already in the country and the attacks would happen in a few months. The translator described the interviewing agents' reaction that the warnings were not specific enough to act upon.[50][51]

In 2004 the 9/11 Commission "found no evidence that Iran or Hezbollah was aware of the planning for what later became the 9/11 attack." Just before their report was published the committee received evidence which caused to add to the report that the topic required further investigation.[52]

On December 22, 2010, a United States Federal Judge signed a default judgment holding Iran, the Taliban and al-Qaeda liable following an open court hearing in which the evidence was produced by the plaintiffs' attorneys which they said showed that Iran assisted the hijackers. 9/11 commission members and witnesses who claimed they were Iranian defectors and members of Ministry of Intelligence and National Security and the Iranian Revolutionary Guards also testified during the hearing. The suit Havlish, et al. v. bin Laden, et al was brought in 2001 by Fiona Havlish whose husband died in the North Tower. Abolghasem Mesbahi, who claimed he was a former Ministry of Intelligence operative in charge of Iran’s espionage operations in Western Europe testified that he was part of a task force that designed contingency plans for unconventional warfare against the United States code-named Shaitan dar Atash/Satan in Flames which included crashing hijacked passenger airliners into the World Trade Center, the Pentagon, and the White House, and that in the summer of 2001 he received three coded messages telling him to activate the plan. An Iranian government memorandum was presented as evidence that Iran's Supreme Leader Ayatollah Khamenei had pre knowledge of the attacks.[53][54] Several days after the ruling a spokesperson for Iran's Foreign ministry said charges that Iran “had a hand in planning the attacks and that one of al-Qaeda’s members was present inside the country is baseless” and said "With the repetition of such claims to back its political aims the U.S. is putting the peace and security of the world in jeopardy,”.[55]

In February 2012 President Obama's Director of National Intelligence James Clapper testified before the Senate Armed Services Committee that "Iran has harbored al-Qaida leaders, facilitators," and that they have been "under house arrest conditions. (Iran's rulers) have had this sort of standoff arrangement with al-Qaida, allowing (al-Qaida) to exist (inside Iran), but not to foment any operations directly from Iran, because they're very sensitive about, 'Hey, we might come after them there as well.'... So there has been this longstanding, as I say, kind of, shotgun marriage, or marriage of convenience."[52]


It was reported that the Mossad informed the Federal Bureau of Investigation (FBI) and Central Intelligence Agency (CIA) in August 2001 that as many as 200 terrorists were slipping into the United States and planning "a major assault on the United States." The Israeli intelligence agency allegedly cautioned the FBI that it had picked up indications of a "large-scale target" in the United States and that Americans would be "very vulnerable."[56]

In September 2001, The New York Times and Israeli newspaper Haaretz reported that four hours after the attack, the FBI arrested five Israelis who had been filming the smoking skyline from the roof of a white van in the parking lot of an apartment building, for "puzzling behavior". They were charged with illegally residing in the United States and working there without permits. The Israelis were said to have been videotaping the disaster with what was interpreted as cries of "joy and mockery".[57][58] Police found the van and a search revealed $4,700 in cash hidden, along with foreign passports and a boxcutter which aroused suspicions and led to the detention of the occupants. The men were held in detention for more than 2 months, during which time they were subjected to interrogation and lie detector tests, before being deported back to Israel; one of the men (Paul Kurzberg) refused to take the test for 10 weeks, and then failed it.[59]

The five men worked at the company Urban Moving Systems, owned and operated by Dominik Suter. After the men were arrested the FBI searched their offices and questioned Suter, however Suter fled to Israel before he could be questioned further. Eventually, Suter's name appeared on the May 2002 FBI Suspect List, along with the Sep 11 hijackers and other suspected extremists.[60]

According to a former CIA chief of operations for counterterrorism Vince Cannistraro, there was speculation that Urban Moving Systems may have been a front for an intelligence operation investigating fund-raising networks channeling money to Hamas and Islamic Jihad. On March 15, 2002, The Jewish Daily Forward claimed that the FBI had concluded that the van's driver, Paul Kurzberg, and his brother Sivan, were indeed Mossad operatives, who were in America "spying on local Arabs".[61] ABC news cited this report on June 21, 2002, adding that the FBI had concluded that the five Israelis had no foreknowledge of the attacks.[62]

In March 2001, the US Office of the National Counterintelligence Executive had issued a warning about people identifying themselves as "Israeli art students" attempting to bypass security and gain entry to federal buildings, and even to the private residences of senior federal officials. A French intelligence agency later noted "according to the FBI, Arab terrorists and suspected terror cells lived in Phoenix, Arizona, as well as in Miami and Hollywood, Florida, from December 2000 to April 2001 in direct proximity to the Israeli spy cells". The report contended that Mossad agents were spying on Mohammed Atta and Marwan al-Shehi, two of leaders of the 9/11 hijack teams.[63][64][65][66] In 2002 several officials dismissed reports of a spy ring and said the allegations were made by a Drug Enforcement Administration agent who was angry that his theories had been dismissed.[67]

Iranian PresidentMahmoud Ahmadinejad said in an August 2010 speech that no "Zionists" were killed in the attacks since, according to him, "one day earlier they were told not go to their workplace." He also remarked, "What was the story of September 11? During five to six days, and with the aid of the media, they created and prepared public opinion so that everyone considered an attack on Afghanistan and Iraq".[68] However, contrary to such conspiracy theories about Jews being warned not to go to work that day, the number of Jews who died in the attacks is variously estimated at between 270 and 400,[69][70][71] while a few Israelis died in the attack as well.[72]


On December 5, 2007, French authorities filed preliminary charges against Guillaume Dasquié, a reporter for the daily Le Monde, for publishing state secrets related to the 9/11 hijackings. Dasquié's April 16 article in Le Monde, titled "September 11: the French had long known" reported that the General Directorate of External Security (DGSE), had warned the U.S. of a possible terrorist plot that involved al-Qaeda hijacking planes and crashing them into buildings some eight months before 9/11. The article contained excerpts from a 328-page classified DGSE report on al-Qaeda activities which included maps, analyses, graphics, and satellite photos.[73]


Moderate elements of the Taliban are reported to have given the USA advance warning of the attacks.[74] The BBC reports that Wakil Ahmed Muttawakil, the Taliban's Foreign Minister, sent the USA an advance warning of the attack following a tip-off he received from Tohir Yo‘ldosh, the leader of the Islamic Movement of Uzbekistan. Like al-Qaeda, the Taliban allowed the Islamic Movement of Uzbekistan to place training camps in Afghanistan. Tohir Yo‘ldosh was reported to have been concerned that if al-Qaeda was not stopped prior to launching the attacks, the USA would retaliate against all of Afghanistan, which would have a negative effect on his movement's efforts.

Possible warnings given to individuals[edit]

There have been claims that some individuals received warnings in advance of the attacks.[75]

  • It is often alleged that San Francisco Mayor, Willie Lewis Brown, Jr. canceled his flight plans for September 11 after receiving a warning late on September 10 from what he described as his airport security.[76] In fact it was Brown who first called his security staff at the airport, to check on his flight for the following morning, and they then warned him that he should be cautious about flying. Brown says, "they always alert me when I ought to be careful," and he decided to fly anyway.[77] In September 2006, Willie Brown responded to these escalating conspiracy rumors by calling them an "ongoing myth."[78]
  • Odigo Messenger reported that two of their employees who were working in an Odigo office in Herzliya Pituah in Israel,[79] received a derogatory English electronic instant message, on the day of the attack, non-specifically threatening them that a terrorist attack would happen.[80] They did not mention this to their employer until after they heard reports of a terrorist attack in America on the news, after which they informed the company's management, who traced the IP and contacted the FBI.[81] However, the threatening message did not mention the location of an attack. The notes ended with an anti-Semitic slur.[82] Odigo Vice President of Sales and Marketing Alex Diamandis later said that the message did not identify the United States or the World Trade Center as to be involved in the event, and that "it could easily be coincidence."[83][84]
  • Silverstein Properties who, according to the New York Times, had planned to meet on September 11 on the 88th floor of one of the towers to "discuss what to do in the event of a terrorist attack," but canceled the meeting late on September 10 "because one participant could not attend."[85]
  • Susan Lindauer asserts that she and other intelligence colleagues were aware of the attacks in April 2001, and that Richard Carl Fuisz had advised in August 2001 against traveling to New York.[86]
  • Parke Godfrey, a professor of computer science at York University in Toronto, Ontario testified in United States v. Susan Lindauer that he had been warned by Lindauer on several occasions of a "massive" attack on southern Manhattan that would involve planes and the possibility of a thermonuclear weapon.[87]

Other related events[edit]

On September 6, 2001, a freshman from a class of Pakistani immigrants at New Utrecht High School in Bensonhurst, Brooklyn was overheard by his English teacher, Antoinette DiLorenzo, to say that the two World Trade Center towers "won't be standing there next week." After DiLorenzo reported the incident on September 13, the youth and his older brother were questioned by the FBI and local police. According to police, the youth admitted to making the comment but he and his brother said he had been kidding.[88]

Kurt Sonnenfeld, a former videographer for the Federal Emergency Management Agency (FEMA) who documented the aftermath of the attacks at the World Trade Center complex, claims that he has videotapes proving that U.S. government officials had prior knowledge of the 9/11 attacks. Sonnenfeld is currently living in Argentina, where Denver police are seeking his extradition on charges of murdering his wife.[89]

On August 30, 2001, an online posting was made with the subject "911". It warned, "Something is going to happen tomorrow . . . REPENT!" On September 4, 2001, the author of the first message, "Xinoehpoel" wrote, "Wait 7 days". This was dismissed by people reading the discussion at the time, but seven days after the message, on September 11, the World Trade Center and the Pentagon were attacked.[90]

See also[edit]


  1. ^Graham, Bradley (September 16, 2001). "At the Pentagon: Response Hampered by Confusion, Lack of Preparedness". The Washington Post. Archived from the original on September 17, 2001.  Also published as: "Pentagon was unprepared for attack", "Pentagon explains why it didn't evacuate building", "Pentagon Unprepared for 'Something We Had Never Even Thought Of'"
  2. ^The Public Education Center.
  3. ^Lumpkin, Beverly (May 18, 2002). "Who Will Be the Red Flag Scapegoats?". ABC News. p. 4. Retrieved July 8, 2013. 
  4. ^"99 Report Warned Of Suicide Hijacking". USA TODAY. May 17, 2002. 
  5. ^ abComplete 911 Timeline: Key WarningsArchived March 6, 2008, at the Wayback Machine..
  6. ^Did Bush Know? :: Warning Signs of 9–11 and Intelligence Failures :: (by Nafeez Mosaddeq Ahmed) – Media Monitors Network.
  7. ^ abNORAD had drills of jets as weapons By Steven Komarow and Tom Squitieri, USA TODAY. Retrieved 2010-01-13.
  8. ^[1] Charles Aldinger, "Pentagon crash scenario rejected before Sept. 2001", Reuters, April 14, 2004. Archived October 23, 2009.
  9. ^LA Times.
  10. ^Lumpkin, John (2002). "Agency planned exercise on Sept. 11 built around a plane crashing into a building". Boston Globe. Retrieved June 12, 2011. 
  11. ^part 2, pp. 209, 212.
  12. ^part 2, p. 212.
  13. ^Stocks Inquiry: Millions of shares sold before disaster by James Doran, The Times, September 18, 2001.
  14. ^Tom Bogdanowicz and Brooks Jackson (September 24, 2001). "Probes into 'suspicious' trading". CNN. Retrieved 2011-07-07. 
  15. ^SEC wants data-sharing system: Network of brokerages would help trace trades by terrorists October 19, 2001. Retrieved March 24, 2009.
  16. ^Bin Laden rigged oil and gold prices – bank chief September 23, 2001. Retrieved March 24, 2009.
  17. ^Unusual Option Market Activity and the Terrorist Attacks of September 11, 2001Archived May 28, 2008, at the Wayback Machine. by Allen M. Poteshman. Retrieved 2010-01-12.
  18. ^Statement of Mindy Kleinberg to the National Commission on Terrorist Attacks Upon the United States March 31, 2003.
  19. ^page 51 of the Commission Report, PDF.
  20. ^"Computer disk drives from WTC could yield clues". CNN. December 20, 2001. 
  21. ^"Das Geheimnis der verkohlten Festplatten". Der Spiegel. December 18, 2001. 
  22. ^"German Firm Probes Final World Trade Center Deals". Fox News. December 17, 2001. 
  23. ^"Geheimsache World Trade Center". ZDF News. March 11, 2002. 
  24. ^National Commission on Terrorist Attacks Upon the United States (October 18, 2003). "FBI Bfiefing on Trading"(PDF).  
  25. ^Allen M. Poteshman. "Unusual Option Market Activity and the Terrorist Attacks of September 11, 2001". 16. The Journal of Business: 670–675. JSTOR 10. 
  26. ^Marc Chesney; et al. (January 2010). "Detecting Informed Trading Activities in the Options Markets". Social Sciences Research Network. SSRN 1522157. 
  27. ^Wing-Keung Wong; et al. (April 2010). "Was there Abnormal Trading in the S&P 500 Index Options Prior to the September 11 Attacks?". Social Sciences Research Network. SSRN 1588523. 
  28. ^9/11 Commission Report Executive Summary, p. 2.
  29. ^9/11 Commission Report Executive Summary, p. 6.
  30. ^Cameron, Carl (May 17, 2002). "Clues Alerted White House to Potential Attacks". Fox News. 
  31. ^Meacher, Michael (September 6, 2003). "This war on terrorism is bogus". The Guardian Unlimited – Comment. London: Guardian Newspapers Limited. Retrieved June 11, 2006. 
  32. ^Phucas, Keith (June 19, 2005). "Missed chance on way to 9/11". The Times Herald. Shelley Meenan. Retrieved August 3, 2006. [permanent dead link]
  33. ^United States Congress. ""U.S. Intelligence." " Congressional Record—House. Washington, D.C.: GPO, June 27, 2005. 109th Cong., 1st sess. HR H5244.
  34. ^Goodwin, Jacob (n.d.). "Did DoD lawyers blow the chance to nab Atta?". GSN: Government Security News. Edward Tyler. Archived from the original on April 5, 2006. Retrieved August 3, 2006. 
  35. ^United States Congress. ""U.S. Intelligence." " Congressional Record—House. Washington, D.C.: GPO, June 27, 2005. 109th Cong., 1st sess. HR H5250. Retrieved August 3, 2006.
  36. ^"statement"(PDF).  (32.1 KB)
  37. ^More pre-9/11 US intelligence connections to al-Qaeda exposed and spun Online Journal.Com August 24, 2005 pdf.
  38. ^Claim about 9/11 takes new twistSan Francisco Chronicle August 19, 2005.
  39. ^WELDON RESPONDS TO OMISSION OF ABLE DANGER FROM 9/11 REPORT, August 12, 2005. Retrieved 2010-01-12.
  40. ^Rowley, Coleen (May 21, 2002). "Coleen Rowley's Memo to FBI Director Robert Mueller". Archived from the original on June 2, 2002. Retrieved September 26, 2013. 
  41. ^FBI eMails concerning Moussaoui.
  42. ^Kirk, Michael; Jim Gilmore (2002). "The Man Who Knew". Transcript of Frontline program #2103. WGBH Educational Foundation. Retrieved June 11, 2006. 
  43. ^Crogan, Jim (2002). "Another FBI Agent Blows the Whistle". LA Weekly News. LA Weekly, LP. Retrieved June 11, 2006. 
  44. ^Grigg, William Norman (2002). "Did We Know What Was Coming?". The New American magazine. American Opinion Publishing Incorporated. Archived from the original on May 28, 2006. Retrieved June 11, 2006. 
  45. ^"Graham book: Inquiry into 9/11, Saudi ties blocked". Miami Archived from the original on September 7, 2004. 
  46. ^'Direct line' between 9/11 terrorists, Saudi government, claim ex-US Senators The Expresse Tribune with The International Herald Tribune March 2, 2012
  47. ^"Hijackers Lived With FBI Informant". CBS News. September 9, 2002. 
  48. ^JFK and 9/11 – Insights Gained from Studying Both by Dr. Peter Dale Scott, December 20, 2006. Retrieved 2010-01-12.
  49. ^What Went Wrong by Seymour M. Hersh, The New Yorker, October 8, 2001. Retrieved 2010-01-12.
  50. ^April 2, 2004 'I saw papers that show US knew al-Qa'ida would attack cities with aeroplanes' The Independent.
  51. ^FBI & 9/11 – by Sibel Edmonds.
  52. ^ ab