A court in Pakistan on Thursday acquitted all four defendants in the 2002 murder of American journalist Daniel Pearl, the lawyers and the court record said.

A two-judge bench of the Sindh High Court headed by Justice Mohammad Karim Agha delivered the ruling on the defendants’ appeals in the southern port city of Karachi.

The court exonerated all four, including the key accused, British-born Ahmed Omar Saeed Sheikh, better known as Sheikh Omar, declaring that the prosecution had failed to prove the case against them.

However, the judges found Sheikh guilty of being involved in abduction for ransom of the slain journalist, and sentenced him seven years in jail, defense lawyer Khawaja Naveed Ahmed told Anadolu Agency.

"Since Omar Saeed Sheikh has already served more than seven years in jail, he together with other three will [also] be set free," Ahmed said.

In June 2002, an anti-terrorist court sentenced Sheikh to death and his co-accused Fahad Naseem, Salman Saqib, and Sheikh Adil to life for the abduction and beheading of the Wall Street Journal reporter.

Pearl, a former South Asia bureau chief of the Journal, had been kidnapped in January 2002 and killed after a month in Karachi, when he was researching on a story about religious extremism.

His dismembered body was found on the northern outskirts of Karachi four months after his disappearance.

In 2011, an investigative report by Georgetown University in Washington, D.C. claimed that Sheikh and the other three accused had been wrongly convicted in Pearl's murder case.

The investigation led by Pearl's colleague, Asra Ansari, who had accompanied him during his Pakistan visit, claimed that the actual man behind his abduction and beheading was Khalid Shaikh Mohammad, the self-proclaimed mastermind of 9/11 terrorist attacks on Washington and New York.

Mohammad, who was arrested by Pakistani security forces and handed over to the U.S. in 2003, is currently awaiting trial at the US base in Guantanamo Bay, Cuba.