But the government of President Pervez Musharraf has refused the offers, saying it was capable of conducting any investigations itself. However, with calls growing inside and outside Pakistan for some outside review, the Pakistani government seems to have backed away from its earlier position.  A State Department official said Monday that the United States had been pressing Islamabad to allow international involvement in the inquiry to give it credibility with Ms. Bhutto’s supporters and others.  The American official, who spoke on condition of anonymity following diplomatic custom, said that Pakistan had quietly been discussing options with Scotland Yard, and that the F.B.I. was ready to fly forensic experts to Pakistan. “They’re trying to hammer something out over the next couple of days,” the official said of senior Pakistani officials.  Senator Chuck Hagel, a Nebraska Republican on the Foreign Relations Committee who met Mr. Durrani on Monday to pay his respects, said he told the ambassador that it was essential for Pakistan to open its investigation to outside help to quell conspiracy theories and accusations of a cover-up.  “Openness and transparency here is critical,” Mr. Hagel said in a telephone interview. “The Pakistani government wants an optic that says, ‘We have nothing to hide.’”  Daniel S. Markey, a former South Asia expert at the State Department, said Monday that the Pakistani government had lost credibility with its shifting version of events of Ms. Bhutto’s death.  “The government has been reluctant to bring in anyone because it suggests they can’t conduct an investigation and it makes them look weak,” he said. “But as long as they continue to bungle it, it makes them look weak and, even worse, it makes them look complicit.”  Allowing outside experts to join the inquiry will probably not satisfy Mr. Musharraf’s fiercest critics, including Asif Ali Zardari, Ms. Bhutto’s husband, who has renewed his call for a United Nations investigation, aided by British authorities.  If allowed in, international forensic experts would have several hurdles. Ms. Bhutto has been buried and her family for now has ruled out exhuming her body for an autopsy. The fiery crime scene itself was hosed down by the authorities after the attack, washing away evidence, American officials said.  A version of this article appears in print on , on Page A6 of the New York edition with the headline: In Reversal, Pakistan Welcomes Outside Help With an Inquiry on Bhutto. Order Reprints| Today's Paper|Subscribe
Pakistan’s ambassador to the U.S. said his government would not endorse a separate inquiry modeled after one carried out by the U.N. after the assassination of Rafik Hariri of Lebanon in 2005.