Nek Muhammad,a tribal warlord,knew he was being followed.
On a hot day in June 2004,the Pashtun tribesman was speaking by satellite phone in a compound in South Waziristan. He asked one of his followers about the strange,metallic bird hovering above him. Less than 24 hours later,a missile tore through the compound,killing him and several others.
A Pakistani military spokesman was quick to claim responsibility for the attack.
That was a lie.
Muhammad and his followers had been killed by the CIA,the first time it had deployed a Predator drone in Pakistan to carry out a targeted killing.
He was not a top operative of al-Qaeda,but a Pakistani ally of the Taliban who led a tribal rebellion and was marked by Pakistan as an enemy of the state. In a secret deal,the CIA had agreed to kill him in exchange for access to airspace it had long sought so it could use drones to hunt down its own enemies.
That back-room bargain,described in detail for the first time in interviews with more than a dozen officials in Pakistan and the US,is critical to understanding the origins of a covert drone war that began under the Bush administration,was embraced and expanded by President Obama,and is now the subject of fierce debate.
The deal,a month after a blistering internal report about abuses in the CIAs network of secret prisons,paved the way for the CIA to change its focus from capturing terrorists to killing them,and helped transform the agency into a paramilitary organisation.
The CIA has since conducted hundreds of drone strikes in Pakistan that have killed thousands of people,Pakistanis and Arabs,militants and civilians alike. Neither American nor Pakistani officials have ever publicly acknowledged what really happened to Muhammad details of the strike that killed him,along with those of other secret strikes,are still hidden in classified government databases.
But in recent months,calls for transparency from members of Congress and critics on both the right and left have put pressure on Obama administration to offer a fuller explanation of the goals and operation of the drone program,and of the agencys role.
Pakistani officials had,for several years,balked at the idea of allowing armed CIA Predators to roam their skies. But Muhammads rise to power forced them to reconsider.
The CIA had been monitoring the rise of Muhammad,but officials considered him to be more Pakistans problem than Americas. George J Tenet,the then CIA director,authorised officers in the agencys Islamabad station to push Pakistani officials to allow armed drones.
As the battles raged in South Waziristan,the station chief in Islamabad paid a visit to Gen Ehsan ul Haq,the ISI chief,and made an offer: If the CIA killed Muhammad,would the ISI allow regular armed drone flights over the tribal areas?
In secret negotiations,the terms of the bargain were set. Pakistani intelligence officials insisted that they be allowed to approve each drone strike,giving them tight control over the list of targets. And they insisted that drones fly only in narrow parts of the tribal areas ensuring that they would not venture where Islamabad did not want the Americans going: Pakistans nuclear facilities,and the mountain camps where Kashmiri militants were trained for attacks in India.
The ISI and the CIA agreed that all drone flights in Pakistan would operate under the CIAs covert action authority meaning that the US would never acknowledge the missile strikes and that Pakistan would either take credit for the individual killings or remain silent.
Maj Gen Shaukat Sultan,Pakistans military spokesman,said at the time that al-Qaeda facilitator Nek Muhammad and four other militants had been killed in a rocket attack by Pakistani troops.
Any suggestion that Muhammad was killed by the Americans,or with American assistance,he said,was absolutely absurd.
The report has been adapted from The Way of the Knife: The CIA,a Secret Army,and a War at the Ends of the Earth, to be published on Tuesday.