Conspiracy theorists – or 9/11 skeptics as they prefer to be called – have pointed to the failure of the U.S. intelligence community to prevent the 9/11 attacks from occurring as proof the whole thing was a plot engineered by the U.S. government.

In fact, 9/11 skeptics argue there was no 'failure' at all – that the CIA, FBI and National Security Agency played a part in 9/11, or at the very least knew the attack was coming and let it occur anyway. According to the skeptics 9/11 gave the Bush administration the justification to clampdown on civil liberties and invade Afghanistan and Iraq to ensure future supplies of oil.

The intelligence community, and the Joint Inquiry investigation into the failure of intelligence, paint an entirely different view of events. While they admit they had an enormous amount of evidence and information that an attack was in the works – and even had some of the hijackers and their helpers under surveillance at various times – they say this information was lost in the general mountain of intelligence the various agencies gather on a regular basis. Moreover, they say information the FBI, CIA and NSA did collect was not shared among the agencies. Thus, the intelligence community says no one managed to piece together all the warning signs in time. (read more about the Congressional Report)

A third view, explored by the fifth estate, suggests something different altogether: that the evidence pointing to a pending attack was not pursued vigorously (consciously or unconsciously) simply because much of it led back to Saudi Arabia. And that Saudi Arabia holds a special place in the U.S. political, business and intelligence milieu. It's a country that is not held to the same standards of accountability as are other nations. The reason, of course, is America's enormous dependence on Saudi Arabia for oil. Remember: 15 of the 19 hijackers were Saudi citizens.

Here are some of the more significant moments of the intelligence failure that point to this thesis:

The Bojinka plot is uncovered in the Philippines. In 1995 Filipino police raid an al Qaeda bomb-making factory. Among the belongings they find is a laptop computer, which contains a number of startling terror plots, including a plan to assassinate the Pope, and to put terrorists on a dozen American jumbo jets and blow them up in midair. Another plan was to dive-bomb a plane into the CIA headquarters.

Two of the men who got away from the raid were Ramzi Yousef, the mastermind of the 1993 bombing of the World Trade Center, and Khalid Shaykh Mohammed who would go on to become the architect of 9/11 itself. This is probably the first time the idea of using planes as a weapon comes to the CIA's attention.

Over the next few years, intelligence intercepts suggest this idea is gathering steam within al Qaeda. In 1998 the US intelligence community receives information that a group of unidentified Arabs planned to fly an explosive-laden plane from a foreign country into the World Trade Center. In the fall of that same year, more information was uncovered that bin Laden's next plot against U.S. involved explosive-laden aircraft and he was trying to establish a cell within the U.S.

in 1996, Valerie Donahue, a special agent with the FBI in Chicago, investigates a chemical company that appears to be an investment fraud scheme. The company is owned in part by the International Islamic Relief Organization (IIRO), Saudi Arabia's most powerful charity that is funded by members of the Saudi royal family. The IIRO is also one of the biggest distributors of monies to terrorist groups like al Qaeda. Donahue found that large sums of money, in excess of $1.2-million, had been transferred from the IIRO to the Chicago company. Donahue's report mentions large amounts going to the IIRO from "an account maintained in the United States by the embassy of a foreign government, which has provided IIRO with approximately $400,000."

This foreign embassy is most likely the Saudi embassy, given the IIRO's close ties to the Saudi government. Chances are, if the FBI had investigated IIRO at this time, and its possible ties to the Saudi embassy, it would have had understood its support of terrorism within America. At the time, the IIRO had its U.S. offices in Falls Church, Virginia, a town where support for the 9/11 hijackers was strong, and where two of the hijackers stayed in the months leading up to 9/11.

The FBI open an investigation into the activities of the World Assembly of Muslim Youth (WAMY), and two men involved with the organization who are cousins of Osama bin Laden in 1996. WAMY is also based in Falls Church, Va. The investigation is dropped after a few months and only restarted a few days after 9/11. WAMY is known for its support of terrorist activities.

The CIA writes a lengthy report on Islamic charities that fund terrorism. The IIRO is profiled, noting that it is "affiliated with the Muslim World League (MWL), a major international organization largely financed by the government of Saudi Arabia." Those connected to the IIRO, the report says, include Ramzi Yousef, mastermind of the 1993 World Trade Centre attack, and Osama bin Laden. In fact, many of the charities listed in the report are connected to Saudi Arabia.

In July 1996, a truck bomb destroys a U.S. air force barracks in al-Khobar in Saudi Arabia, killing 19 US air force personnel. In their investigation, the FBI is soon stonewalled by the Saudi government. The Clinton administration eventually stops pursuing the investigation because they don't want to upset relations between Saudi Arabia and Iran – the country alleged to have carried out the bombing.

After Al-Kobar and under pressure from the U.S., the Sudanese government expels Osama bin Laden from the Sudan, where he has been living for five years. However, the U.S. decides not to arrest bin Laden and rejects an offer from the Sudanese government to provide the CIA with their own intelligence files on the al Qaeda leader. The Saudis are not interested in arresting bin Laden either. He is allowed to travel to Afghanistan in a plane that flies over Saudi Arabia.

ROBERT BAER (read his interview with the fifth estate)
CIA field officer Robert Baer quits the Agency in 1997. He has grown disenchanted with his superiors' lack of interest in keeping an eye on events in the Middle East. Prior to his departure, Baer checks the CIA computers and finds no evidence the Agency is collecting information on Saudi Arabia. While stationed in the Middle East and Caspian region, Baer had seen growing evidence of the financial and ideological support Saudi Arabia was giving to various radical Muslim groups, in particular the Muslim Brotherhood. However, the CIA was never tasked to investigate Saudi Arabia or draw up National Intelligence Estimates (NIE) – a report that evaluates the security threat posed by a country. Baer concludes that oil and other economic interests – including major defense and aerospace contracts – have swayed Washington to turn a blind eye to what the Saudis are doing.

German intelligence begins to conduct surveillance, including phone taps, on Arab students studying in Hamburg in 1998. This German city has a large Arab and Muslim student attending local technical colleges. In fact, many of the key 9/11 hijackers are recruited into the plot while attending schools in Hamburg, becoming known as the "Hamburg cell".

German wiretaps pick up the name of key players in the 9/11 plot, including Marwan al-Shehi, the eventual pilot of Flight 175, the plane that hits the south tower of the World Trade Center on 9/11. The Germans pass on this information to the CIA. Later it is learned the Hamburg cell is in contact with an official from the Saudi embassy in Berlin and is in phone contact with a number of sheiks in Saudi Arabia.

As early as 1998 an agent with the FBI's Oklahoma office informs an agent with the office's counter-terrorism squad that he's observed many men of Middle Eastern origin taking flight school training. The FBI received also reports that a terrorist organization might be planning to bring students to the US for flight training.

Much later, a Phoenix, Az.-based FBI counter-terrorism agent writes a lengthy memo in which he says it has been noticed that a high number of Arabs, possibly with connections to al Qaeda, are taking flying lessons in local flight schools. His memo is ignored by FBI headquarters.

In April 1999, Nawif al-Hazmi and Khalid al-Mihdhar – two of the 9/11 hijackers – obtain U.S. visas from the U.S. consulate in Jeddah, Saudi Arabia. They then travel back to Afghanistan for special training. At this time, Al-Hazmi's name comes up in NSA intercepts connecting him to a suspected terrorist facility in the Middle East.

Both Al-Hazmi and Al-Mihdhar's names come up in NSA intercepts linked to a safe house in Yemen used by Al Qaeda as clearing house of information. This information is passed onto the FBI and CIA that same year. Al-Mihdhar had a US visa allowing to come and go as he pleased. These intercepts inform the CIA of an important al Qaeda meeting to take place in Malaysia in 2000.

Despite being known to U.S. authorities both Al-Hazmi and Al-Mindhar are not placed on a government watch list until August 2001.

A high level planning meeting of Al Qaeda takes place in an apartment building in Kuala Lumpur in Malaysia in January of 2000. Among the participants are Khalid al-Mihdhar, Nawif al-Hazmi and Khalid Shaykh Mohammed, the architect of the 9/11 attack. The CIA asks the Malaysian secret police to place the meeting under surveillance. Many photos and videotape of the meeting's attendees are taken, which are passed on to the CIA. The FBI is also aware of the al Qaeda meeting in Malaysia. This get-together is where it is believed the details of the 9/11 attack is sketched out.

Shortly after the Malaysia meeting, al-Mihdhar and al-Hazmi are met my Omar al-Bayoumi, a Saudi national who works for the Saudi civil aviation authority. Just prior to picking up the two would-be hijackers, Al-Bayoumi meets with a member of the Saudi consulate in LA – a man later connected to terrorist activity. Al-Bayoumi takes al-Mihdhar and al-Hazmi to San Diego, puts them up in an apartment, signs a lease, holds a party for them, enrolls them in flight school and gives them money. Later, the FBI concludes that al-Bayoumi is likely a Saudi intelligence agent. Al-Bayoumi also passes on thousands of dollars to the hijackers that originate from Princess Haifa, wife of Prince Bandar Saudi ambassador to the US.

Later that year, Al-Hazmi and Al-Mihdhar move into the home of a local imam in San Diego, Abdussattar Shaikh. The imam is an FBI informant. In fact, Shaikh holds meetings with his FBI handler while al-Hazmi and al-Mihdhar sit in a room next door. Shaikh contends he was never told what mission the hijackers were on. His FBI handler, meanwhile, was never informed by his superiors to look out for al-Hazmi and al-Mihdhar.

In February 2000, the Intelligence Community obtained information that Osama Bin Laden was making plans to assassinate U.S. intelligence officials, including the Director of the FBI.

In March 2000, the Intelligence Community obtained information regarding the types of targets that operatives in Bin Ladin's network might strike. The Statue of Liberty was specifically mentioned, as were skyscrapers, ports, airports, and nuclear power plants. The intelligence community also obtained information indicating Bin Ladin was planning attacks in specific West Coast areas, possibly involving the assassination of several public officials.

The USS Cole, sitting in a harbor off the coast of Yemen, is attacked by a boat laden with explosives, killing 17 sailors in October 2000. The FBI arrive in Yemen to investigate the attack, which they conclude is an al Qaeda operation. Eventually the U.S. State Department kicks out the FBI to prevent hurting relations with Yemen. The FBI again sees evidence of links to the USS Cole attack with Saudi Arabia but cannot pursue them.
In early 2001, the U.S. Drug Enforcement Administration (DEA) notices evidence of an Israeli art student spy ring operating in the U.S. Working in small groups, the students go door-to-door selling art. When the DEA interview some of the students, they discover they are often the sons and daughters of high officials in the Israeli military and many have intelligence training.

One of these Israeli cells is located near the home of Mohammed Atta in Florida during the time that Atta – the pilot of Flight 11 on 9/11 – is receiving his flight training. The DEA orders the students back to Israel. In August of 2001, the Israeli intelligence agency, Mossad gives the CIA the names of 200 people they consider to be terrorist threats. The Mossad were apparently interested in Atta and his accomplice, Marwan al-Shehi.

In April 2001, the Intelligence Community obtained information from a source with terrorist connections who speculated that Bin Ladin would be interested in commercial pilots as potential terrorists. The source warned that the United States should not focus only on embassy bombings, that terrorists sought "spectacular and traumatic" attacks, and that the first World Trade Center bombing would be the type of attack that would be appealing. The source did not mention a timeframe for any attack. Because the source was offering personal speculation, the information was not disseminated within the intelligence community.

The CIA will later determine that they had information that Khalid Shaykh Mohammed, architect of 9/11 and al Qaeda's other attacks, was entering the U.S. as late as May 2001, despite the fact he is a well-known figure in the terrorist netherworld, his name first becoming known to the CIA as early as 1995.

In August, President Bush receives a detailed and lengthy presidential daily briefing from the CIA in which Osama Bin Laden and al Qaeda's aim of launching an attack against the US is mentioned. To this day, the Bush White House refuses to release the contents of this briefing to Congressional inquiries into 9/11.

Zacarias Moussaoui is arrested by the FBI for his suspicious behavior at a flight school in Chicago just weeks prior to 9/11. He is considered the 20th hijacker who was sent over from Germany after another member of the Hamburg cell is denied entry into the U.S. Two days after Moussaoui's arrest, an FBI agent in Chicago sends a note to his superiors noting that Moussaoui seemed to be part of a plot to seize control of an airplane. The agent asks for permission to get a warrant to search Moussaoui's belongings. The FBI headquarters argues against this. Later a laptop is found among Moussaoui's possessions which gives details about the 9/11 plot.