ISLAMABAD (WSJ) - A Pakistani court Thursday ordered the release of the British national convicted in 2002 as the mastermind of the kidnapping and killing of Wall Street Journal reporter Daniel Pearl, according to the suspect’s lawyer and a government attorney.

The court in the southern city of Karachi ruled that Omar Sheikh be released from a temporary detention order that had kept him in jail since the same court overturned his conviction eight months ago, both lawyers said.

In April, the court set aside the death sentence handed down to Mr. Sheikh for terrorism, kidnapping for ransom, and murder, downgrading it to the fewerer crime of kidnapping. As kidnapping carries a maximum of seven years in jail, and Mr. Sheikh had already been locked up for 18 years at that point, he was eligible for release.

Three accomplices who were sentenced to life in prison at the same 2002 trial had their convictions completely overturned in the April ruling.

However, Mr. Sheikh and the three others remained in prison after Pakistani authorities used emergency detention powers.

On Thursday, the judges ruled that the use of those powers was not justified in this case, the accused’s lawyer, Mahmood Sheikh, said, adding that his client is not allowed to leave the country.

The lawyer said he expected Mr. Sheikh to be freed this week, along with three accused accomplices.

“The court has directed that they will not be arrested by any agency, no action detrimental to their liberty will be taken,” Mr. Sheikh’s lawyer said.

A senior government lawyer, Salman Talibuddin, who serves as Attorney General for the southern province of Sindh and who appeared for the authorities in the case, confirmed the court had ordered the release. The court is expected to issue a written ruling later Thursday.

The authorities and the Pearl family have separately appealed against the April overturning of Mr. Sheikh’s conviction to the Supreme Court. The next hearing in that separate case is due in early January.

Mr. Pearl, then the Journal’s bureau chief for South Asia, was reporting on militant networks in Pakistan when he was kidnapped in Karachi in January 2002 and killed days later.