The missile killed at least 13 civilians. Reports that a number of senior al-Qaida operatives also died were never confirmed, as none of their bodies were found.

The associate who allegedly hosted al-Zawahri, a timber merchant and tribal chief called Haji Nader, was later arrested by U.S. Special Forces and taken to the American air base in Bagram, Afghanistan, said Commander Youssef, police chief in Naray, where the military also has a base.

Youssef declined to give further details, but Pakistani intelligence officials and local residents said the arrest was made in May in Kunar province and that Nader's family in Pakistan had since received a letter from him, sent from Bagram. The U.S. military declined to confirm the information.

Talk of al-Zawahri's whereabouts persists. In Pakistan's Bajur region, opposite Kunar, tribesmen say al-Zawahri moves with a small entourage between Pakistan and Afghanistan. They say al-Zawahri briefly visited near Damadola in July and got engaged or married to the teenage daughter of another local associate, Kawas Khan, and the ceremony was attended by tribal elders including pro-Taliban militants.

Pakistani intelligence confirmed the reports but Aurakzai, who is now the provincial governor, maintained they were speculation.

Getting solid information is a dangerous business.

In Pakistan's border region, resentment has grown over the presence of the army. Until the Sept. 11 attacks, the military had left the semi-autonomous region alone since Pakistan won independence from Britain in 1947.

Aurkazai said that since late 2004, about 70 tribesmen have been killed, mostly for cooperating with the government; other officials report more than 100 such deaths. A senior officer in Pakistan's intelligence service, speaking on condition of anonymity, said at least 30 of its informants were assassinated, often beheaded and their heads displayed in a public place.

On Aug. 7, the decapitated corpse of a 38-year-old former militant-turned-informer, Loi Khan, was dumped in a North Waziristan village. An attached note read: "See this man's body. Anyone spying on us will face the same end."

Another intelligence officer said it was harder for Pakistani agents to operate in their own tribal areas than inside archrival India. "In the enemy country, we know who is our enemy but in the tribal areas it is extremely difficult to differentiate between the enemy and the friends," he said.

Pakistani intelligence officials say bin Laden and al-Zawahri likely live separately, each with a tight entourage of trusted Arab retainers and several rings of defense, the outermost ring manned by local militants.