Khalid Sheikh Mohammed (sometimes also spelled Khalid Shaikh Mohammed; among at least fifty pseudonyms; born March 1, 1964) is an Islamist militant held by the United States at the Guantanamo Bay detention camp under terrorism-related charges. He was named as "the principal architect of the 9/11 attacks" in the 9/11 Commission Report. Sheikh Mohammed was a member of Osama bin Laden's al-Qaeda organization, leading al-Qaeda's propaganda operations from around 1999 until late 2001. He confessed to FBI and CIA agents to a role in many of the most significant terrorist plots over the last twenty years, but his interrogators' use of enhanced interrogation techniques has caused some to question certain aspects of his confessions.

By the time the Bojinka plot was discovered, Mohammed had returned to Qatar and his job as a project engineer at the country's Ministry of Electricity and Water. He traveled in 1995 to Sudan, Yemen, Malaysia, and Brazil to visit elements of the worldwide jihadist community, although no evidence connects him to specific terrorist actions in any of those locations. On his trip to Sudan, he attempted to meet with Osama Bin Laden, who was at the time living there, aided by Sudanese political leader Hassan al-Turabi. After the US asked the Qatari government to arrest Mohammed in January 1996, he fled to Afghanistan, where he renewed his alliance with Abdul Rasul Sayyaf. Later that year, he formed a working relationship with Bin Laden, who had settled there.  Bin Laden and his colleagues relocated their operations to Afghanistan at this time. Abu Hafs al-Masri/Mohammed Atef, bin Laden's chief of operations, arranged a meeting between bin Laden and Mohammed in Tora Bora sometime in mid-1996, in which Mohammed outlined a plan that would eventually become the quadruple hijackings of 2001. Bin Laden urged Mohammed to become a full-fledged member of Al Qaeda, but he continued to refuse such a commitment until around early 1999, after the 1998 U.S. embassy bombings in Nairobi and Dar es Salaam.  Mohammed moved his family from Iran to Karachi, Pakistan, in 1997. That year, he tried unsuccessfully to join mujahideen leader Ibn al-Khattab in Chechnya, another area of special interest to Mohammed. Unable to travel to Chechnya, he returned to Afghanistan. He ultimately accepted bin Laden's invitation to move to Kandahar and join al-Qaeda as a full-fledged member. Eventually, he became leader of Al Qaeda's media committee.

Did Khalid work with anyone else in his planning?
Abu Hafs al-Masri/Mohammed Atef,