The Pentagon has dropped charges against a Saudi citizen alleged to have been
the "20th hijacker" in the 11 September 2001 attacks on the US.
Mohammad al-Qahtani was one of six Guantánamo Bay inmates charged with murder
and war crimes in February.
The Pentagon said the case against the other five defendants would proceed.
Prosecutors are seeking the death penalty against the suspects in a case before
military tribunals at the US prison camp in Guantánamo Bay.
A Pentagon official said the charges against Mohammad al-Qahtani had been dropped
"without prejudice", meaning they could be reinstated.
The US military gave no reason for its decision.
But lawyers for the defendant say they believe the charges were dropped because
he "was tortured" under interrogation.
The decision could have implications for the other five suspects, whose lawyers
claim that similar treatment was meted out to them, the BBC’s Adam Brookes reports
Authorities say Mr Qahtani failed to take part in the 9/11 attacks because
he was denied entry into the US by an immigration official.
He was refused entry at Orlando in Florida in August 2001 and returned to Dubai.
He was later detained in Afghanistan and transferred to Guantánamo Bay.
In 2006, he recanted accusations he had made against fellow detainees of having
links to al-Qaeda.
His lawyer told Time magazine the statements had been extracted under torture.
The Saudi was reportedly submitted to stress positions, sleep deprivation and
humiliation at Guantánamo.
Officials said he had been subjected to a harsh interrogation authorised by
former US Defence Secretary Donald Rumsfeld.
Four planes were hijacked by 19 men in the 11 September attacks. Two hit the
World Trade Center in New York, another the Pentagon in Washington and the fourth
crashed in Pennsylvania.
About 3,000 people were killed.
The five suspects still facing trial at Guantánamo include the alleged mastermind
of the plot, Khalid Sheikh Mohammed.
Story from BBC NEWS:
See also: Why has the US dropped 9/11 charges?