The Pentagon is dropping charges against a Saudi detained at Guantanamo Bay, Cuba, who was alleged to have been the "20th hijacker" in the Sept. 11, 2001, attacks on the U.S.

Mohammed al-Qahtani was one of six men facing murder charges before a U.S. military tribunal at the U.S. naval base in connection with the attacks that killed nearly 3,000 people in New York and Washington.

But U.S. military defence lawyers confirmed to the Associated Press on Monday that a Pentagon official has finalized the charges only against the other five, including Khalid Sheik Mohammed, the alleged architect of the plan.

U.S. officials have said al-Qahtani was subjected to harsh treatment authorized by former Defence Secretary Donald H. Rumsfeld, including the controversial technique of "waterboarding" — or strapping a person down and pouring water over his or her cloth-covered face to create the sensation of drowning.

The others who have been charged are:

  • Ramzi bin al-Shibh, alleged to have been the main intermediary between the hijackers and leaders of al-Qaeda.
  • Ali Abd al-Aziz Ali, known as Ammar al-Baluchi, a nephew of Khalid Sheik Mohammed, accused of being Mohammed's lieutenant for the 2001 operation.
  • Al-Baluchi's assistant, Mustafa Ahmed al-Hawsawi.
  • Walid bin Attash, a detainee known as Khallad, who investigators allege selected and trained some of the hijackers.