A British-born Pakistani man on death row over the 2002 killing of American journalist Daniel Pearl will remain in jail for another three months despite his acquittal by a lower court earlier this year, according to a government order.

The development was announced by prosecutors during a brief hearing of the high-profile case at Pakistan’s Supreme Court, which is to decide whether the key suspect in Mr Pearl’s murder, Ahmed Omar Saeed Sheikh, should stay in jail following his acquittal.

The court convened for an appeal by Mr Pearl’s family, seeking to keep Sheikh on death row over the beheading of the Wall Street Journal reporter.

According to Faisal Siddiqi, the lawyer representing Mr Pearl’s family, government prosecutor Fiaz Shah told the judges he needed more time for paperwork in the case. The judges adjourned the hearing until October 21.

Mr Siddiqi, who had expected the court to rule against Sheikh’s acquittal on Wednesday, said he still hopes such a decision will come before the suspect’s new 90-day detention expires.

Sheikh’s defence lawyer, Mahmood Shaikh, told the Associated Press he had expected his client to walk free on Wednesday. “My client cannot he kept in jail for an indefinite period,” he said.

The lawyer said he has already challenged Wednesday’s three-month extension in Sheikh’s detention in Sindh province and that his motion would be taken up by a local court on October 19.

Under Pakistan’s legal system, the appeal process against Sheikh’s acquittal could take years. The government has opposed his release, despite his acquittal in April, saying it would endanger the public.

Sheikh was convicted of helping lure Mr Pearl to a meeting in Karachi where he was kidnapped.

The journalist had been investigating the link between Pakistani militants and Richard C Reid, dubbed the “Shoe Bomber” after trying to blow up a flight from Paris to Miami with explosives hidden in his shoes.

The lower court’s April ruling acquitted Sheikh and three other accomplices, who had been sentenced to life in prison for their role in the plot. The lower court found Sheikh guilty of a lesser charge of abduction, which he is also appealing against.

The acquittal stunned the US government, Mr Pearl’s family and journalism advocacy groups. In 2002, when Pakistani police were still searching for Mr Pearl, a video received by US diplomats showed his beheading.

His family says it received assurances from the US State Department that it was closely following Sheikh’s acquittal and subsequent appeals.

Mr Pearl, 38, of Encino, California, was abducted on January 23 2002. In Sheikh’s original trial, emails between him and Mr Pearl presented in court showed he gained the journalist’s confidence sharing their experiences as both waited for the birth of their first child. Mr Pearl’s wife Marianne gave birth to a son, Adam, in May 2002.

Evidence entered into court accused Sheikh of luring Mr Pearl to his death, giving him a false sense of security as he promised to introduce him to a cleric with militant links.