British-born al Qaeda leader Ahmed Omar Saeed Sheikh and three aides, whose release was ordered by a court in Karachi on Thursday, are expected to walk out of prison on Saturday.

Sheikh and his aides had been convicted for the murder of The Wall Street Journal journalist Daniel Pearl in 2002. Sheikh was one of three terrorists released by the government of Atal Bihari Vajpayee in late 1999 after Pakistani militants hijacked an Indian Airlines flight in Kathmandu. India released Sheikh, Masood Azhar and Mushtaq Ahmed Zargar in exchange for about 150 passengers after the Indian Airlines flight was diverted to Kandahar, Afghanistan, by the hijackers. Masood Azhar went on to found the Jaish-e-Mohammed.

Sheikh had been serving a prison term in India for kidnapping western tourists.

A Pakistani court on Thursday ordered the release of Sheikh and his three aides—Fahad Naseem, Salman Saqib and Sheikh Adil—who were convicted and sentenced in the case.

A two-judge bench of the Sindh High Court, presided over by Justice K.K. Agha, 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.

In April, a two-judge Sindh High Court bench commuted the death sentence awarded to Sheikh for killing Daniel Pearl 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 act. Their continued detention was challenged in the Sindh High Court, which ordered their release. However, it asked 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.

Omar Saeed Sheikh, who is of Pakistani origin, was born in London in 1973. Sheikh studied at the London School of Economics, but did not complete his graduation. He was arrested in India in 1994.

Sheikh has also been accused of transferring money to one of the attackers involved in the September 11 attacks on the US in 2001.