ISLAMABAD, Pakistan — A regional Pakistani court on Thursday overturned the murder conviction and death sentence of Ahmed Omar Saeed Sheikh, the man convicted in the 2002 killing of U.S. journalist Daniel Pearl. The court also overturned the convictions of three other men connected to Pearl's death.

Prosecutor Faiz Shah said he would appeal the decision in Pakistan’s Supreme Court. All four men will remain in custody for at least 90 days on the grounds of “public safety,” according to a ruling issued by the Home Department of Sindh province.

Pearl, a Wall Street Journal reporter, was kidnapped in January 2002 in Pakistan, where he was researching the connection between a radical Islamic preacher and Richard Reid, who attempted to blow up an airliner with explosives in his shoes.

Saeed, a British-born Pakistani who was implicated in other kidnappings, had been sentenced to death for Pearl’s murder and kidnapping. The High Court of Sindh on Thursday overturned the murder conviction and downgraded the kidnapping charge, which carries a seven-year sentence.

Because Saeed has served 18 years, he is eligible for release, as are the other three men whose convictions were overturned: Fahad Naseem, a computer expert; Salman Saqib, a religious activist; and Sheikh Adil, a police officer.

The defendants’ lawyer, Khawaja Naveed, said the evidence against Saeed “was very weak” and could prove only kidnapping, not murder.

In a statement Thursday, the Wall Street Journal said: “We continue to seek justice for the murder of Daniel Pearl. Danny was a cherished colleague and we will always honor his memory and service.”

Pearl was told he was meeting with a radical cleric when instead he was kidnapped, held for days and beheaded. When Saeed was convicted months later, he was sentenced for planning Pearl’s kidnapping and murder.

But a 2011 investigation by the Center for Public Integrity’s Pearl Project found that Khalid Sheikh Mohammed, the self-proclaimed mastermind of the 9/11 attacks, killed Pearl. Mohammed was captured in Pakistan in 2003 and is being held at the U.S. military prison at Guantánamo Bay, Cuba. He is not charged in the journalist’s killing.

Pakistan was under immense pressure in 2002 to find the people responsible for Pearl’s killing. At the time of Saeed’s conviction, defense attorneys raised questions about the weight of evidence against him.

The murder has been seen as marking the beginning of a trend of militant groups targeting journalists in conflict zones. In 2014, the Islamic State filmed the beheadings of several its hostages, including journalist James Foley.

George reported from London. Paul Schemm in Dubai contributed to this report.