Khalid Sheikh Mohammed ( sometimes also spelled Khalid Shaikh Mohammed ; among at least fifty pseudonyms ; born March 1 , 1964 ; or April 14 , 1965 ) is a Pakistani 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 ''
9/11 attacks
September 11 attacks
Khalid Sheikh Mohammed