Wiki: PENTTBOM

PENTTBOM is the codename for the Federal Bureau of Investigation's probe into the September 11 attacks of 2001, the largest criminal inquiry in the FBI's history. Its name stands for 'Pentagon/Twin Towers Bombing Investigation'. The investigation was launched on September 11, 2001 and involved 4,000 special agents and 3,000 professional employees.[1][2]...

....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. To avoid getting into classified detail, we will just state that these were manipulated in a fraudulent manner in ways that have been associated with al Qaeda."
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https://en.wikipedia.org/wiki/PENTTBOM