Some friends and supporters of Ms. Bhutto questioned the C.I.A. conclusions, especially since the former leader was buried before a full forensic investigation had been conducted. The British government has since sent a team from Scotland Yard to participate in the investigation into the assassination.  “The C.I.A. appears too eager to bail out its liaison services in Pakistan, who are being blamed by most Pakistanis,” said Husain Haqqani, a former adviser to Ms. Bhutto and a professor at Boston University.  “Given the division inside Pakistan on this issue, it might be better to have an international investigation under the aegis of the U.N.,” Mr. Haqqani said.  Within days of Ms. Bhutto’s assassination, Pakistani authorities announced they had intercepted communications between Mr. Mehsud and militant supporters in which they said the leader had congratulated his followers for the assassination and appeared to take responsibility for it.  Mr. Mehsud, through a spokesman, has denied responsibility for the killing and suggested that the assassins were directed by Pervez Musharraf, Pakistan’s president and a longtime rival of Ms. Bhutto’s.  Members of Ms. Bhutto’s political party, along with some of her family members, have also challenged Pakistani government accounts of the attack. They have blamed Mr. Musharraf for failing to provide Ms. Bhutto with adequate protection as she campaigned around the country, and some have hinted that elements of Pakistan’s government may have been behind the assassination.  American and Pakistani officials have blamed Mr. Mehsud’s followers for many recent suicide attacks against government, military and intelligence targets in Pakistan. Based in the South Waziristan tribal areas along the Pakistan-Afghanistan border, Mr. Mehsud runs training camps and dispatches suicide bombers beyond the border areas in both countries, the officials say. He is also believed to have links to the Arab and Central Asian militants who have established a stronghold in the tribal areas.  Government officials in Pakistan and independent security analysts say they believe that the Qaeda network in Pakistan is increasingly made up of homegrown militants who have made destabilizing the government a top priority.  American intelligence officials say they believe that Al Qaeda has steadily built a safe haven in the mountainous tribal areas of western Pakistan, constructing a band of makeshift compounds where both Pakistani militants and foreign fighters conduct training and planning for terrorist attacks.  This has led to mounting frustration among intelligence and counterterrorism officials, many of whom believe that the United States should take more aggressive unilateral steps to dismantle terrorist networks in the tribal areas. The Bush administration is currently considering proposals to step up covert actions in Pakistan against the Qaeda network.  A version of this article appears in print on , on Page A8 of the New York edition with the headline: C.I.A. Sees Qaeda Link In the Death Of Bhutto. Order Reprints| Today's Paper|Subscribe
The C.I.A. has concluded that the assassins who killed Benazir Bhutto were directed by Baitullah Mehsud, a Pakistani militant leader.