The courier who led American special forces to Osama bin Laden was an al-Qa'ida computer expert who helped train the September 11 hijacking team, according to leaked US government files.
American spies discovered the role of a man known as Abu Ahmed al-Kuwaiti four years ago and were monitoring him for the past two.
When he made a phone call in 2010, he unknowingly led the Americans to the doorstep of the world's most wanted terrorist. He was said to have been among those killed alongside Bin Laden in the raid.
Secret American military files from Guantanamo Bay obtained by WikiLeaks suggest that al-Kuwaiti may have been with Bin Laden ever since he disappeared from the Tora Bora mountains in Afghanistan in 2001.
The file for Muhammad Mani al-Qahtani, the Guantanamo detainee who was to have been the "20th hijacker" on September 11, refers to him receiving computer training for the mission from al-Kuwaiti.
Khalid Sheikh Mohammed, the mastermind of the September 11 attacks, ordered al-Kuwaiti to teach al-Qahtani how to send emails because it was "safer than talking on the phone", according to the file.
The file suggests that the courier's identity was provided by another al-Qa'ida operative, Hassan Ghul, who was captured in Iraq in 2004 and interrogated by the CIA.
He told the Americans that al-Kuwaiti travelled with Bin Laden and was seen in Tora Bora. The picture that emerges from al-Qahtani's Guantanamo file supports statements given by US officials, who named Ghul as the "linchpin" in the operation to find Bin Laden.
One official said a phone call from al-Kuwaiti led the US directly to the walled compound in Abbottabad, where Bin Laden was shot.
As a courier, al-Kuwaiti, whose real name may have been Sheikh Abu Ahmed, was key to maintaining Bin Laden's secrecy and safety for almost 10 years.
All of Bin Laden's communications were conducted through trusted couriers because he knew that US intelligence would be monitoring telephone and email conversations for any clue as to his whereabouts.
The CIA gained crucial information confirming the role of al-Kuwaiti from two inmates at Guantanamo Bay -- Khalid Sheikh Mohammed and Abu Faraj al-Libi. Al-Libi's file refers to his contact with Bin Laden's personal courier, although he gives another name. The very next sentence in the document includes a reference to al-Libi living in Abbottabad. (© Daily Telegraph, London)