This story was written by Greg Miller
The CIA maintained a safe house in the Pakistani city of Abbottabad for a small team of spies who conducted extensive surveillance over a period of months on the compound where Osama bin Laden was killed by U.S. Special Operations forces this week, U.S. officials said.
The secret CIA facility was used as a base of operations for one of the most delicate human intelligence gathering missions in recent CIA history, one that relied on Pakistani informants and other sources to help assemble a "pattern of life" portrait of the occupants and daily activities at the fortified compound where bin Laden was found, the officials said.
The on-the-ground surveillance work was part of an intelligence-gathering push mobilized after the discovery of the suspicious complex last August that involved virtually every category of collection in the U.S. arsenal, ranging from satellite imagery to eavesdropping efforts aimed at recording voices inside the compound.
The effort was so extensive and costly that the CIA went to Congress in December to secure authority to reallocate tens of millions of dollars within assorted agency budgets to fund it, U.S. officials said.
Most of that surveillance capability remained in place until the execution of the raid by U.S. Navy SEALs shortly after 1 a.m. in Pakistan. The agency's safe house did not play a role in the raid and has since been shut down, in part because of concerns about the safety of CIA assets in the aftermath, but also because the agency's work was considered finished.
"The CIA's job was to find and fix," said a U.S. official, using Special Operations forces terminology for the identification and location of a high-value target. "The intelligence work was as complete as it was going to be, and it was the military's turn to finish the target."
The official, like others quoted for this article, spoke on the condition of anonymity because they were not authorized to speak for the record. The CIA declined to comment.
U.S. officials provided new details on bin Laden's final moments, saying the al-Qaeda leader was first spotted by U.S. forces in the doorway of his room on the compound's third floor. Bin Laden then turned and retreated into the room before being shot twice -- in the head and in the chest. U.S. commandos later found an AK-47 and a pistol in the room.
"He was retreating," a move that was regarded as resistance, a U.S. official briefed on the operation said. "You don't know why he's retreating, what he's doing when he goes back in there. Is he getting a weapon? Does he have a [suicide] vest?"
Despite what officials described as an extraordinarily concentrated collection effort leading up to the operation, no U.S. spy agency was ever able to capture a photograph of bin Laden at the compound before the raid, or a recording of the voice of the mysterious male figure whose family occupied the structure's top two floors.
Indeed, current and former U.S. intelligence officials said that bin Laden employed remarkable discipline in his efforts to evade detection.
"You've got to give him credit for his tradecraft," said a former senior CIA official who played a leading role in the manhunt. When spotted by surveillance drones a decade earlier, bin Laden "had bodyguards, multiple SUVs and things like that. He abandoned all of that."
The officials also outlined emerging theories as to why bin Laden apparently selected the Pakistani military garrison city of Abbottabad as the place that afforded him the greatest chance to stay alive.
The discovery of bin Laden in Abbottabad has raised suspicion that he was placed there and being protected by elements of the Pakistani military and intelligence service, but U.S. officials said they have seen no conclusive evidence that was the case.
The city, about two hours north of Islamabad by car, offered a number of advantages for the al-Qaeda leader, officials said. Chief among them is that Abbottabad, deep inside Pakistan's borders, is a safe distance from the tribal regions that are patrolled by armed U.S. drones.
U.S. officials said they are convinced that bin Laden, who had long immersed himself among the Pashtun tribes along the border with Afghanistan, was driven from that part of the country by the escalating drone campaign.
"Even five years ago things were dropping from the sky" in Pakistan's tribal region, a U.S. official said. "He probably felt that if he could conceal his presence [in Abbottabad] it would be an unlikely area for the United States to pursue him."
Strikes by conventional U.S. aircraft would have carried enormous risks, both because Pakistan has invested heavily in air detection and defense systems -- to counter any threat posed by India -- and because of the perils of an errant strike.
"All it has to be is about 1,000 yards off and it hits the Pakistan Military Academy," said a CIA veteran of Afghanistan and Pakistan. The city is also home to two regimental compounds, and suburbs occupied by military families.
U.S. officials said there were also disadvantages for bin Laden in residing in Abbottabad, including the fact that the area is relatively welcoming to outsiders, including Pakistanis on vacation, military families being transferred to bases there, and even U.S. soldiers who have at times been sent to Abbottabad to train Pakistani troops.
"Abbottabad is not a place where Islamic extremists went, because it wasn't a stronghold," said the former U.S. intelligence official involved in the bin Laden pursuit. "They preferred places like Peshawar, Quetta or Karachi." When analysts would consider likely locations for the al-Qaeda chief, the official said, "Abbottabad wouldn't be on that list."
The CIA took advantage of that atmosphere to send case officers and recruited informants into Abbottabad undetected, and set up a safe house that functioned as its base.
"That is an Achilles heel for bin Laden, because anybody can go" to Abbottabad, the former CIA official said. "It makes it easier for the CIA to operate."
U.S. officials declined to say how many case officers or informants used the facility, but they stressed that the effort required extraordinary caution because of the fear that bin Laden and those sheltering him might vanish again if spooked.
The CIA began to focus on the compound last summer after years of painstaking effort to penetrate a small network of couriers with ties to the al-Qaeda leader. Once the most important of those couriers led them to the Abbottabad compound, the conspicuous nature of the complex sent up alarms that it might have been built for bin Laden himself.
"The place was three stories high and you could watch it from a variety of angles," the former official said. Moving into the custom-made compound, the former official said, "was his biggest mistake."
When a team of two dozen commandos arrived at the site Monday, one of bin Laden's couriers was the only enemy to open fire, officials said. "They had to blow through some doors and walls," said the U.S. official briefed on the raid. "One door they opened up only to find a [cement] wall behind it."
The SEALs encountered no other armed opposition as they ascended to the top floor, where bin Laden was found. "He was in the doorway and then retreated, and that's where the operators moved in," the senior U.S. official said.
Staff researcher Julie Tate contributed to this report. Special correspondent Haq Nawaz Khan in Abbottabad contributed to this report.