Four men including a British national who were imprisoned for killing Wall Street Journal reporter Daniel Pearl were not present during his beheading but were convicted of murder because Pakistani authorities knowingly relied on perjured testimony and ignored other leads, a report has concluded.
The results of the Pearl Project, an investigation carried out by a team of US journalists and students which spanned more than three years, raise questions about Pakistan's criminal justice system and underscore the limits US officials face in relying on Pakistani authorities.
According to the investigation, the four men convicted in the killing did help kidnap the American journalist. But it said forensic evidence known as "vein-matching" bolsters the confession of al Qaida No 3 Khalid Sheikh Mohammed, the professed mastermind of the September 11 attacks on the US, to having killed Mr Pearl.
The report said at least 14 of 27 people involved in abducting and murdering Mr Pearl in 2002 are thought to remain free. The four who have been convicted could be released if their appeal is ever heard because of false and contradictory evidence used in their trial, it added.
Mr Pearl, 38, was abducted from Karachi on January 23, 2002, while researching a story on Islamist militancy after the September 11 attacks.
On February 21, 2002, a shocking video of his killing was delivered to US officials in Pakistan. His remains were found in a shallow grave on Karachi's outskirts three months later.
Within months of his disappearance, Ahmed Omar Saeed Sheikh, a Londoner of Pakistani heritage, and three accomplices were caught, charged, and convicted of murder and kidnapping.
Sheikh, called the kidnapping's mastermind, was sentenced to death in July 2002. The three others were given life terms, which in Pakistan usually means 25 years.
Since then, the men's appeals have gone nowhere in the courts, despite dozens of hearings. Both the defence and the prosecution blame each other for stalling tactics and there is constant speculation that Sheikh is being protected, possibly by Pakistani intelligence agencies.
Vein-matching is not considered as reliable as fingerprinting, but the CIA and FBI do use it at times to identify suspects, the report said. It involves "extracting the information of the vascular structure of a hand or finger and converting it into a mathematical quantity".