New Delhi/Washington, Apr 2 (IANS): The British-born terrorist involved in the kidnapping and beheading of Wall Street Journal journalist Daniel Pearl 18 years ago, is set to be free after a Pakistani court commuted his death sentence to seven years in prison on Thursday.

Daniel's parents called it a mockery of justice and demanded that the prosecution in Pakistan should appeal the court verdict. "Anyone with a minimal sense of right and wrong now expects Faiz Shah, prosecutor general of Sindh to do his duty and appeal this reprehensible decision to the Supreme Court of Pakistan," Judea Pearl, Daniel's father tweeted.

Apart from Omer Sheikh's commutation of sentence, the other three convicts, Fahad Naseem, Salman Saqib and Sheikh Adil, earlier handed life terms, were set free by the Sindh High court on Thursday. Since Omer Sheikh has been in prison for the past 18 years, his sentence will be counted from the time served, Pakistani media reported.

Washington-based author Asra Nomani, a friend and colleague of Daniel Pearl, who was present in Pakistan at the time of the kidnapping, called the acquittal of Sheikh and three others horrible.

"Eighteen years ago, on January 23, 2002, Omar Sheikh set the trap for the kidnapping of an innocent citizen of humanity, Danny Pearl. Today, Danny is betrayed a second time by this miscarriage of justice that would release Omar Sheikh to walk free on this earth," she said.

"Omar Sheikh is a danger to society. For the sake of all journalists, we must realize justice for Danny," Nomani told IANS over phone.

A prominent member of Harkat ul-Ansar terror group, Sheikh was also involved in the kidnapping and murder of four Western tourists in Kashmir in 1994. He was released from a jail in India, along with terrorist Masood Azhar, in exchange of passengers of the hijacked Indian Airlines flight IC814 in 1999.

In 2002, an anti-terrorism court in Pakistan had convicted Omer Sheikh and other three terrorists for the kidnapping and beheading of Daniel (38) who was researching a story on Islamist terrorists in Karachi.

The defence counsel of the four terrorists had submitted that the prosecution had "miserably failed to prove its case against their clients beyond any reasonable doubt and prosecution witnesses were mostly policemen, whose testimonies could not be relied upon."

A two-judge bench headed by Justice Mohammad Karim Khan Agha decided in their favor on Thursday.