How America killed Osama bin Laden, 'TIP-OFF': Wikileaks

Khalid Sheikh Mohammed (KSM), the mastermind of the 9/11 attacks was repeatedly subjected to interrogated and torture methods including "waterboarding" and stress positions, provided the US' CIA with the name of bin Laden's personal courier, according to US officials.

A second source – also an al-Qaeda "leader" held at Guantanamo Bay – then confirmed the courier's identity, sparking an intense manhunt that resulted in the dramatic final raid.

Secret documents seen by The Daily Telegraph disclose that this second source – the terrorist operations chief, Abu Faraj al-Libi – played a key role in finding "safe havens" for bin Laden and lived in the military town where he was finally found.

The killing of the world's most wanted man as a direct result of information obtained from Guantanamo detainees such as KSM will reignite the debate over whether torture is a legitimate interrogation technique in the "war on terror". Both KSM and al-Libi were subjected to harsh techniques during their interrogations in CIA prisons.

Amnesty International has already warned that the killing of bin Laden must not be used as evidence that torture is "justifiable".

Bin Laden went into hiding shortly after the 9/11 attacks and the White House has been criticised for a series of failures that meant he evaded capture for almost 10 years.

During his time as a fugitive, bin Laden's communications with the outside world were handled by a network of trusted couriers, who carried letters to and from senior al-Qaeda commanders. Using a telephone or the internet would have been too risky as electronic communications were monitored by the US and its allies.

But the CIA revealed that American spies have also been watching many of bin Laden's couriers for years.

"One courier in particular had our constant attention," a senior US government official said. "We identified him as both a protege of Khaled Sheikh Mohammed and Abu Faraj al-Libi."

American spies learned his name four years ago; two years later they pinpointed the general region where he was hiding. Still, it was not until August when they tracked him to the compound in Abbotabad.

Secret US government files on the Guantanamo detainees disclose that al-Libi had several dealings with one key courier for bin Laden, who may be the same aide that led the US to the compound where the al-Qaeda leader was killed.

Al-Libi's Guantanamo file, dated 10 September 2008, states: "In July 2003, detainee [al-Libi] received a letter from UBL's designated courier, Maulawi Abd al-Khaliq Jan, requesting detainee take on the responsibility of collecting donations, organizing travel, and distributing funds to families in Pakistan.

"UBL stated detainee would be the official messenger between UBL and others in Pakistan."

In mid-2003, al-Libi "moved his family to Abbottabad, PK and worked between Abbottabad and Peshawar," according to the file.

In 2001 and 2003, he arranged "save havens" for bin Laden and his deputy, Ayman al-Zawahiri, who is currently still at large.

It may not be a coincidence that the "safe haven" where bin Laden was finally caught was in the Pakistani garrison town where al-Libi lived in 2003.

Al-Libi's file states that he had several further attempted contacts with the courier and set up a shop front to be used as a "drop point" for the meetings in April 2005, one month before he was captured. The courier's name does not appear in KSM's Guantanamo file.