Pearl, the South Asia bureau chief for The Wall Street Journal, was abducted and beheaded for investigating links between Pakistan's spy agency ISI and al-Qaeda
British-born al-Qaeda leader Ahmed Omar Saeed Sheikh and his three aides, whose release in the abduction and murder case of US journalist Daniel Pearl was ordered by a court here, would walk out of the prison on Saturday, police and lawyer said on Friday.
In a surprise move, a two-judge bench of the Sindh High Court on Thursday directed security agencies not to keep Sheikh and other accused under "any sort of detention" and declared all notifications of the Sindh government related to their detention "null and void".
The court observed that the four men's detention was "illegal".
According to the jail superintendent, the four men could not be released from Karachi's Central Jail on Thursday as the prison authorities received orders from the Sindh High Court for their release very late.
According to the legal counsel for the four men, they would now be released on Saturday as Friday is a public holiday in the country.
Meanwhile, the United States on Friday expressed "deep concern" over Sindh High Court’s order to release Sheikh and his aides and said it will continue to monitor any developments in the case.
"We are deeply concerned by the reports of the December 24 ruling of Sindh High Court to release multiple terrorists responsible for the murder of Daniel Pearl. We have been assured that the accused have not been released at this time," the US State Department said in a tweet.
It said that the US will continue to monitor any developments in the case and will continue to support the Pearl family "through this extremely difficult process" while honouring the legacy of Pearl as a "courageous journalist".
The US has been mounting pressure on Pakistan, demanding justice for Pearl.
In April, a two-judge Sindh High Court bench commuted the death sentence of 46-year-old Sheikh to seven years imprisonment. The court also acquitted his three aides who were serving life terms in the case – almost two decades after they were found guilty and jailed.
However, the Sindh government refused to release them and kept them in detention under the Maintenance of Public Order.
Their continuous detention was challenged in the Sindh High Court, which ordered their release. However, it asked authorities to place their names on the no-fly list so that they could not leave the country. It also directed them to appear before the court whenever summoned.
Pearl, the 38-year-old South Asia bureau chief for The Wall Street Journal, was abducted and beheaded while he was in Pakistan investigating a story in 2002 on the links between the country's powerful spy agency ISI and al-Qaeda.
A three-judge apex court bench headed by Justice Mushir Alam is hearing the appeal by the Sindh government and the family of the slain journalist against the acquittal of Sheikh.
Pearl's murder took place three years after Sheikh, along with Jaish-e-Mohammad chief Masood Azhar and Mushtaq Ahmed Zargar, was released by India in 1999 and given safe passage to Afghanistan in exchange for the nearly 150 passengers of hijacked Indian Airlines Flight 814.
He was serving a prison term in India for kidnappings of Western tourists in the country.