Investigators on Saturday tried to piece together the crime scene where a suicide bomber set off a deadly blast on Friday that killed 13 people and injured 71 in Islamabad, Pakistan.
Investigators also searched through a government database to try and determine who the suicide bomber was.
The attack on Friday targeted security forces, but many of those killed were bystanders in the restaurant and market area where the attack occurred.
The explosion followed a clash between demonstrators and authorities at the nearby Red Mosque, which had just been re-opened after an army siege ended two weeks ago after days of fighting that left more than 100 dead. The military action was designed to oust pro-Taliban clerics at the mosque.
Officials vowed Saturday that an inquiry would be launched into the hours that led up to the suicide attack, and specifically why intelligence that warned of a possible strike was not acted upon.
A joint task force of federal police and intelligence agencies has been formed to look into the blast, Interior Minister Aftab Ahmed Khan Sherpao told The Associated Press.
Sherpao said the team was having trouble identifying the bomber because his remains were so badly mangled in the explosion.
"We don't have any information with regard to the suicide bomber," he said.
Late Friday it was revealed that the government had received prior notice of a possible bombing in the market where the blast occurred.
Interior Ministry spokesman Javed Iqbal Cheema said the investigation would determine why that warning wasn't acted upon, but said the tension at the Red Mosque -- located about half a kilometre from the blast-site -- created the circumstances which allowed the attacker to strike.
"If these people had not created such a situation it would not have happened," he said, noting that the mosque was now indefinitely closed.
Angry over the assignment of a cleric from another mosque, the students daubed red paint on the walls (it had been repainted yellow after deadly clashes there two weeks ago) and put up a black flag with two crossed swords -- a symbol of jihad.
The students then battled with police. The students threw stones and the police responded with tear gas.
During the Friday confrontation at the mosque, the students demanded the return of pro-Taliban cleric Abdul Aziz -- who is being detained by the government. His brother, Abdul Rashid Ghazi, died in the siege.
The students forced a government-appointed cleric, intended to lead prayers, to retreat. The prayers were eventually led by another cleric associated with the mosque and the government-appointed cleric was escorted from the compound.
The angry crowds also shouted insults against President Pervez Musharraf.
The Red Mosque siege had triggered unrest, primarily in the Taliban-dominated tribal areas of northwest Pakistan. More than 300 people, mainly police and soldiers, have died in bombings since the siege ended July 10.
A July 17 suicide attack in Islamabad killed 16 at a rally in support of the country's top judge.
In the period leading up to the siege, which ended with the storming of the mosque, clerics had enlisted thousands of its students in a campaign to impose Taliban-style Islamic rule in Islamabad.
With files from The Associated Press
