RAWALPINDI, Aug 18 Three members of the United Nations inquiry commission probing the assassination of former prime minister Benazir Bhutto arrived in Islamabad on Tuesday morning.

Meanwhile, the City Police Officer of Rawalpindi, Rao Mohammad Iqbal, said on Tuesday that the case against Baitullah Mehsud, one of the suspects in the assassination, would be dropped only after due process because his death was yet to be confirmed.

Answering questions after a press conference here, he said that after verification, Baituallh's name would be dropped from the list of 'proclaimed offenders'.

The CPO said that the investigation into the assassination of Benazir Bhutto was transferred by Rawalpindi police to the Federal Investigation Agency (FIA) on the instructions of the federal government.

The federal government, sources said, had sought legal opinion from the law and justice division in this regard. The case is being heard by an anti-terrorism court in Adiala jail in Rawalpindi, which had declared Bailtullah Mehsud a proclaimed offender.

Despite the submission of a charge-sheet after completion of police investigation in which FIA's Special Investigation Group had helped, the FIA had been trying to reinvestigate the case and the federal government believed it was competent to do so. But the government should seek the court's permission, otherwise it might take suo motu action.

Five men were arrested in connection with the assassination.

According to the law division, the trial could not be stopped even if the case was being reinvestigated, and the provincial government would have to be consulted, but legally it was not possible to transfer the investigation to the FIA.

On Monday, the federal government had filed an application with the ATC, seeking postponement of the case hearing.

The application was filed by Deputy Attorney-General Shah Khawar.