PENTTBOM (sometimes referred to as PENTTBOMB[1]) 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.
[2][3] The FBI was able to identify the 19 hijackers within a matter of days as few suspects made any effort to conceal their names on flight, credit card, and other records.
[7] 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.
"[8] 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:[9] Four of the hijackers' passports have survived in whole or in part.
The New York Times reported on September 12 that: "Authorities said they had also identified accomplices in several cities who had helped plan and execute Tuesday's attacks.
"[14] The Washington Post later reported that "In the hours after Tuesday's bombings, investigators searched their files on [Satam] Al Suqami and [Ahmed] Alghamdi, noted the pair's ties to [Nabil] al-Marabh and launched a hunt for him.