By Zaffar Abbas BBC correspondent, Islamabad

Daniel Pearl was kidnapped and beheaded in 2002

Mohammed Hashim Qadeer, who was appearing in court in an unrelated murder case, was arrested last month in Gujranwala in Punjab province.

He was later handed over to Karachi police for further investigations about his possible involvement in the killing of the Wall Street Journal reporter.

Daniel Pearl was abducted and murdered in Karachi in January 2002.

Hashim Qadeer has so far not been charged with involvement in Daniel Pearl's murder.

So when the police produced him before a court in Karachi to seek further remand, he was accused only in an unrelated murder case.

The investigators requested for more time to complete the probe, and the judge allowed a further remand of four days in police custody, and ordered to produce him in the court on 17 August.

Suspicion

At the time of his arrest the police had described Hashim Qadeer as one of the 12 suspects involved in Daniel Pearl's murder.

He was identified as the militant who had arranged the initial meeting between the Wall Street journal reporter and the group that later abducted and murdered him.

Four people have already been tried and convicted in the case, including a British-born militant, Ahmed Omar Saeed Sheikh.

Sheikh, having been sentenced to death, has appealed against the sentence in the high court along with the other three, who have been given life imprisonment.