ISLAMABAD, Pakistan -- Benazir Bhutto's widowed husband accused members of Pakistan's ruling regime of involvement in his wife's killing and called Saturday for a U.N. investigation, as British officers aiding Pakistan's own probe pored over the crime scene.
"An investigation conducted by the government of Pakistan will have no credibility, in my country or anywhere else," Asif Ali Zardari, the effective leader of Bhutto's opposition party, said in a commentary published in The Washington Post. "One does not put the fox in charge of the hen house."
Calls for an independent, international investigation have intensified since the former prime minister was killed Dec. 27 in a shooting and bombing attack after a campaign rally. Opposition activists denounced the government's initial assessment that an Islamic militant was behind the attack and that Bhutto died not from gunshot wounds, but from the force of the blast.
President Pervez Musharraf acknowledged that investigators may have drawn conclusions too quickly and mishandled evidence, including hosing down the site hours after the attack. But he insisted the government was competent to run the investigation with the help of forensic experts from Britain's Scotland Yard. The United States said it did not believe a U.N. investigation was needed.
In an interview to be aired on CBS' "60 Minutes" program Sunday, Musharraf acknowledged that Bhutto may have been shot, CBS reported on its Web site. "Yes, absolutely, yes. Possibility," Musharraf was quoted as saying.
The British investigators arrived at the site of the attack in the city of Rawalpindi under heavy police guard in a convoy of sports utility vehicles. They spoke to local security officials and repeatedly walked from the park where Bhutto held her final campaign rally to the spot outside where her departing vehicle was attacked.
Local police parked a truck where Bhutto's had been, and the British investigators took photographs of it and filmed it from different angles, including from a nearby rooftop.
Zardari said no government investigation would satisfy him. He reiterated his demand for a U.N. probe modeled on the investigation into the death of former Lebanese Prime Minister Rafik Hariri and urged "friends of democracy in the West, in particular the United States and Britain, to endorse the call for such and independent investigation."
"Those responsible -- within and outside of government -- must be held accountable," he wrote.
Also Saturday, the government accused a leading international think tank of "promoting sedition" for urging Musharraf, a key U.S. ally in the war on terror, to resign.
The report by the Brussels-based International Crisis Group called Musharraf "a serious liability, seen as complicit" in Bhutto's death.
In a statement, the government said the report "amounts to promoting sedition" and the group "neither has the credentials, nor the credibility and lacks representational standing specially on Pakistan's national affairs" to comment on Pakistan.
Also Saturday, gunmen shot and killed one paramilitary soldier and wounded two others in the southwestern city of Quetta, said Rahmatullah Niazi, a senior police official. The motive behind the attack was not known, he said.