What started with the discovery of one name four years ago ended a few hours ago with the death of the most wanted fugitive in U.S. history.
The shot to the head that ended Osama bin Laden's life came after months of painstaking intelligence gathering that began when terror suspects in U.S. custody revealed the name of a man they said was bin Laden's trusted courier -- known by his nom de guerre, Abu Ahmed al-Kuwaiti -- the person the Al-Qaeda leader relied on to ferry information to and from his isolated world where electronic communication was too risky.
The courier was also said to be close to Khalid Sheik Mohammed, the self-described mastermind of the September 11, 2001, terror attacks, and Faraj al-Libi, the man who succeeded Mohammed after his capture.
Representative Mike Rogers (Republican-Michigan), the chairman of the House Select Committee On Intelligence, said it was detainee interrogation sessions that produced the first sliver of crucial information that would ultimately lead U.S. authorities to bin Laden's compound in the town of Abbottabad, some 60 kilometers from Islamabad. But he credited the entire U.S. intelligence apparatus with cooperating and pooling their findings.
"When you look at the incredible undertaking of the analysts, of the operators, the case operators in the CIA, the folks at the [National Security Agency] who got just little snippets, little tidbits, and put it all in one place, and started drawing that noose, this was an incredible operation that I argue few countries in the world, if any, could do," Rogers said.
U.S. intelligence officials speaking late on May 1 provided more details of the intelligence-gathering operation and military aspect of the raid, but all spoke anonymously because of the sensitivity of the matter.
Officials said that although they learned the courier's real name in 2007 -- Sheikh Abu Ahmed -- it wasn't until 2009 that intelligence analysts had narrowed his geographic location to somewhere near Islamabad. By August 2010, they had pinpointed his likely location to the compound outside Islamabad, and had begun studying the elaborate three-story structure in earnest.
The 4- and 6-meter-high walls topped with barbed wire, and the 2.5-meter-high wall on an upper balcony struck them as odd. So did the fact that the residents appeared to burn all their garbage and the lack of phone lines and Internet cables going into the house.
A senior administration official said it was a breakthrough moment when intelligence officials realized that the courier they had been tracking for two years was living in a compound so secure it could only be holding an extremely high value target.
National security adviser John Brennan said that before the compound was discovered, intelligence analysts did consider whether bin Laden could be "hiding in plain sight," rather than the proverbial mountain cave. But Pakistan is a large country, he said, and in the end, it was a trail of vaguely interconnected information that led officials to the Al-Qaeda leader's suburban mansion.
"As a result of the information that we had in a very generic way about these couriers and individuals who were [intermediaries] for bin Laden, over time we were able to piece together additional information, get the name [the courier] was known by, his nom de guerre, associate that then, eventually, with his real name, associate that then with other things that that real name was associated with and track it until we got to the compound in Abbottabad," he said.
Obama Says Yes
By September, CIA officials say they believed there was "a strong possibility" that bin Laden was inside. Intelligence officials also say they believed the compound was purpose-built in 2005 to hide bin Laden, who by that time had been a hunted man for almost a decade, after narrowly eluding capture in the mountains of Afghanistan in the 2001 Battle of Tora Bora.
By February, months of additional intelligence work had convinced intelligence officials and White House military advisers that they had probably indeed found bin Laden. They brought what they knew to U.S. President Barack Obama, who agreed with the analyses and green-lit what a senior administration official described as an "aggressive course of action."
"There was nothing that confirmed that bin Laden was at that compound and, therefore, when President Obama was faced with the opportunity to act upon it, the president had to evaluate the strength of the information and then make what I believe was one of the...gutsiest calls of any president in recent memory," Brennan said.
In mid-March, Obama began holding meetings of his national security team to start planning the operation. Over the next six weeks, there were five meetings, during which members of the team debated whether to bomb the compound, which they knew housed some 22 people. But Obama vetoed that approach, wanting both proof of bin Laden's death and as few additional casualties as possible.
A raid by U.S. Special Operations Forces, Navy SEALS, was Obama's preferred course of action, and on April 19 he gave preliminary approval to the operation.
This would have been the logical point at which Washington would tell Islamabad what it knew and what it was planning. But this operation was so secret that nothing was said outside a small circle of U.S. officials. Brennan said the Americans "didn't contact the Pakistanis until after all of our people and all of our aircraft were out of Pakistani airspace."
Real-Time Monitoring From Washington
On the morning of April 29, Obama sent a formal authorization for the raid to CIA Director Leon Panetta, who the day before he had nominated to replace retiring Defense Secretary Robert Gates. (The top U.S. commander in Afghanistan, David Petraeus, will replace Panetta at the CIA in a sign of how deeply integrated the U.S. intelligence community and U.S. military have become on Obama's watch.)
Panetta was given lead command of the operation and throughout the raid was in direct communication with the SEAL team from a conference room at CIA headquarters that had been turned into a command center.
Details of the dramatic military operation were reported by "Politico's" Mike Allen, who spoke to unnamed senior administration officials. Originally scheduled for April 30, bad weather delayed the operation until May 1. The helicopter that carried the team into the compound arrived at 12:30 a.m. and appeared to stall as it hovered overhead. Once on the ground, it wouldn't start up, so the team loaded the crippled chopper with bombs and blew it up, not knowing if a replacement airlift out would arrive.
During the actual raid, bin Laden "tried to resist the assault force" and was reportedly shot "in the face." A military commander communicated that bin Laden was dead to Washington, where applause erupted at the CIA.
At the White House, Brennan says officials were following every moment. "We were able to monitor in a real-time basis the progress of the operation from its commencement to its time on target to the extraction of the remains and to then the [departure] off of the target," he said. "It was probably one of the most anxiety-filled periods of time, I think, in the lives of the people who were assembled here yesterday."
The U.S. team then gathered all the evidence they could find in the house, photographed bin Laden's body, and were flown out on replacement helicopters.
The man it took the United States nearly 10 years to find had been dispatched in less than 45 minutes.