PENTTBOM

Three of the hijackers carried copies of an identical handwritten letter[4][5] (in Arabic) that was found in three separate locations: the first, in a suitcase of hijacker Mohamed Atta that did not make the connection to American Airlines Flight 11 that crashed into the North Tower of the World Trade Center; the second, in a vehicle parked at Washington Dulles International Airport that belonged to hijacker Nawaf al-Hazmi; and the third at the crash site of United Airlines Flight 93 in Shanksville, Pennsylvania.

According to the testimony before the House Intelligence Subcommittee on Terrorism and Homeland Defense on October 3, 2001 given by J. T. Caruso—the Deputy Assistant Director of the FBI's Counterterrorism Division, "translations of the letter indicate an alarming willingness to die on the part of the hijackers."[6]

According to testimony by Susan Ginsberg, a staff member of the National Commission on Terrorist attacks upon the United States, in the January 26, 2004, Public Hearing:

Four of the hijackers' passports have survived in whole or in part. Two were recovered from the crash site of United Airlines flight 93 in Pennsylvania. These are the passports of Ziad Jarrah and Saeed al Ghamdi. One belonged to a hijacker on American Airlines flight 11. This is the passport of Satam al Suqami. A passerby picked it up and gave it to a NYPD detective shortly before the World Trade Center towers collapsed. A fourth passport was recovered from luggage that did not make it from a Portland flight to Boston on to the connecting flight which was American Airlines flight 11. This is the passport of Abdul Aziz al Omari.

In addition to these four, some digital copies of the hijackers passports were recovered in post-9/11 operations. Two of the passports that have survived, those of Satam al Suqami and Abdul Aziz al Omari, were clearly doctored. These passports were manipulated in a fraudulent manner in ways that have been associated with al Qaeda.

The passport of hijacker Satam al-Suqami was found a few blocks from the World Trade Center.[7][8]

According to the 9/11 Commission, the passports of two of the Flight 93 hijackers were also found intact in the aircraft's debris field.[9]

The doctored passport of hijacker Abdulaziz Alomari was found in Mohamed Atta's left-behind luggage.[9]

When examining Mohamed Atta's left-behind luggage, the FBI found important clues about the hijackers and their plans. His luggage contained papers that revealed the identity of all 19 hijackers, and provided information about their plans, motives, and backgrounds.[10] The FBI was able to determine details such as dates of birth, known and/or possible residences, visa statuses, and specific identities of the suspected pilots. None of these documents have been scrutinized by independent legal experts.[11]