Trial runs began in early April at Bagram Air Force Base in Afghanistan.
In a sealed-off area known as Camp Alpha, members of a secret group of elite hunters/killers began running through a seemingly impossible mission.
Without advance notice, they would fly through darkness deep into a military garrison city in the heart of Pakistan, assault a heavily fortified compound — then return with the world's most wanted man, dead or alive.
They practiced on a one-acre mock-up of the compound, fighting their way in, fighting their way out, timing and coordinating every move as they tried to anticipate what they would encounter.
Within a few weeks, Navy SEAL Team Six was ready to go — whenever President Barack Obama gave the order.
The command came late last week.
A chopper, and a tweet
The clatter of a helicopter shattered the midnight silence, jolting Sohaib Athar.
An IT consultant in Pakistan, Athar had moved to Abbottabad last year to get away from the teeming megacity of Lahore, where his wife and son had been severely injured in a crash with a police van.
Social media kept the English-speaker connected to the outside world. So he sent a tweet: "Helicopter hovering above Abbottabad at 1 a.m. (is a rare event)."
Minutes later, a second tweet: "A huge window-shaking bang here in Abbottabad Cantt. I hope it's not the start of something nasty."
As Athar and the rest of the world would soon learn, the din rocking the valley enclave early Monday was more than just a military exercise or a skirmish with terrorists.
Detainees provided name
The operation that ended the decadelong hunt for bin Laden was rooted in a 4-year-old breakthrough by American intelligence officials: a nickname Abu Faraj al-Libi, No. 3 in the al-Qaida command structure until his 2005 capture, had given them for a top courier bin Laden used in order to avoid sending traceable electronic messages.
U.S. officials refused to identify the courier, but they told The Washington Post that detainees at Guantanamo had identified him "as one of the few al-Qaida couriers trusted by bin Laden [and] indicated he might be living with or protecting Osama bin Laden."
Find the courier, they reasoned, and they would find bin-Laden.
Operatives had "been working this target for years, years, years. They finally found the guy who led to the guy who led to the guy who led to the guy," an official told the Post.
In 2009 came another breakthrough: A tapped phone call between the courier and another al-Qaida operative allowed them to link the man to his nickname.
Officials narrowed the search to areas of Pakistan where the now-identified courier and his brother were known to operate.
Last August, they finally located the brothers' residence: a mansionlike compound in Abbottabad.
'Unique' compound
Abbottabad, 3,500-feet above sea level, is a getaway for those with the means to escape Pakistan's steaming summers.
The compound owned by the courier and his brother was in a prime location, less than a mile from the Pakistani military academy and even closer to the maple-lined fairways of the Abbottabad golf club.
Built in 2005, the $1 million compound was large — about eight times the size of surrounding homes — and secure. Even a third-floor balcony was shielded behind a security wall.
CIA analysts spent several weeks examining satellite photos and intelligence reports, determining that the compound had no telephone or Internet connections. The residents, they found, were apparently so concerned about security that they burned their garbage rather than putting it out for collection.
An official who described the compound to The Wall Street Journal called it "extraordinarily unique" — a structure the analysts were sure sheltered a higher-value target than a courier.
The Guardian reported that the two brothers had no known source of income, adding to CIA suspicions. The CIA also learned that there was a family living with them, and that the composition of this family matched bin Laden's.
By September, officials told The New York Times, they were convinced there was a "strong possibility" that bin Laden himself was hiding within the walls, which rose up to 18 feet and were protected by barbed wire and two security gates.
It was an astounding conclusion. The compound was just 35 miles from Pakistan's capital, Islamabad, and far from bin Laden's assumed redoubts in Taliban-friendly tribal villages of the inaccessible mountains.
Signing the order
The CIA reported its hypothesis to President Barack Obama. But it took several more months of intense detective work to satisfy him that there was a sound basis to launch action based on the findings.
On March 14, the countdown to the raid began as Obama held the first of a series of National Security Council meetings to develop options for capturing or killing bin Laden.
The council met again March 28, as Obama simultaneously worked to avoid a government shutdown over a budget dispute. U.S. counterterrorism officials considered bombing the compound, an option that was discarded by the White House as too risky, particularly if it turned out bin Laden was not there.
More meetings came on April 12 and 19 before the final session Thursday.
On Friday, before flying to Tuscaloosa, Ala., to inspect the damage from last week's deadly tornado outbreak, Obama met at 8:20 a.m. with National Security Adviser Thomas Donilon, counterterrorism adviser John O. Brennan and other senior aides in the Diplomatic Room at the White House.
It was there that he signed the order for the operation.
Donilon prepared the formal orders and convened senior national security officials that afternoon to make final plans.
He chose to keep Pakistan in the dark about the raid — a decision prompted by years of mistrust. Much of that mistrust centered on Islamabad's repeated insistence that bin Laden was not in the country. American intelligence had long indicated otherwise.
However, American diplomatic officials in Peshawar, in Pakistan's restive far northwest, were told to leave Friday for safer locations, though they were not told why.
40 minutes of gunfire
On Sunday, Obama played an early round of golf, but cut it short after nine holes and hurried back to the White House as it became clear the raid was ready to go.
After a final meeting between the president and his national security team at 2 p.m., the 40 elite SEAL Team Six commandos, officially known as the Navy Special Warfare Development Group, shortened to DevGru, took off in four U.S. helicopters from an undisclosed location in Afghanistan, whose eastern border lies about 120 miles west of Abbottabad.
After the departure of the helicopters, Obama called President Asif Ali Zardari of Pakistan to tell him about the strike, and Obama's advisers called their Pakistani counterparts. "They agree that this is a good and historic day for both of our nations," Obama said later.
Fox News reported that on arrival at the compound, the helicopters dropped "about 24" SEALs, who launched into a firefight with the occupants of the compound.
A resident of the area, Omar Khan, told The Wall Street Journal that the troops landed about 1:10 a.m. local time Monday — 4:10 p.m. EDT on Sunday.
"The entire area was rocked with a massive explosion," Khan was quoted as saying. "A massive exchange of firing took place which continued for more than half an hour."
The military said one of the helicopters experienced mechanical trouble, and the pilot was forced into a "hard landing." It was blown up and left behind. Photos taken later in the day showed Pakistani soldiers removing its shrouded wreckage on a trailer.
Despite the setback, the team pressed ahead, exchanging fire with the courier and his brother. Within minutes, both men were fatally wounded.
The commandos then began moving into the interior of the building, room by room, until they reached the upper-floor living quarters where bin Laden and his family were staying. After nearly 40 minutes on the ground, the SEAL team was finally poised to confront bin Laden.
What words were passed among the Americans and the terrorist, if any, are not publicly known. But shortly before 2 a.m., the SEALs burst into the room to find an armed bin Laden, with one of his two wives positioned in front of him.
"The woman presumed to be his wife ... was shielding bin Laden," Brennan told The Washington Post. She was "in the line of fire," he added, and was killed, along with one of bin Laden's adult sons.
Bin Laden himself was shot at least once in the head and died instantly, U.S. officials said.
News footage from inside the rooms of the compound showed the aftermath of a ferocious struggle, with blood-soaked carpets and overturned furniture.
All told, four men and one woman lay dead. Live television footage from a Pakistani news network showed the compound in flames.
Officials said the commandos had gone in with the intention of capturing bin Laden, although few planners expected that would happen.
U.S. officials said the shot that killed bin Laden was fired by an American and not by bin Laden or another al-Qaida member trying to fulfill his leader's longtime vow never to be taken alive.
Even before the commando team left the compound, a bin Laden family member — reportedly another of his wives — identified his body.
'We got him'
A White House photo shows Obama and his national security team, anxious and expectant, sitting at a conference table in the Situation Room as the mission plays out. Obama is tieless and grim-faced, his eyes fixed on a monitor.
Hillary Clinton, holding a hand to her mouth, and Robert Gates, his arms folded across his chest, gaze at the same point, their concentration total.
Brennan, the president's chief counterterrorism adviser, was in the room, though not in the photo. He told the Post that Obama and his aides monitored the action "in real time" and that "the minutes passed like days."
When it became clear later that bin Laden was dead, he said, the president's reaction was, "We got him."
Buried at sea
Carrying bin Laden's body, the three remaining helicopters departed. Also aboard was what officials said was "the mother lode of intelligence" — personal computers, thumb drives and electronic equipment seized during the raid.
"They cleaned it out," one official told POLITICO. "Can you imagine what's on Osama bin Laden's hard drive?"
Despite a brief scare as Pakistani fighter jets scrambled, the helicopters safely reached Afghanistan, where technicians began the process of confirming the body was indeed bin Laden's — looking for identifying markings and even measuring the height of the famously tall terrorist leader, reputed to be at least 6 foot 4.
At 3:50 p.m., officials relayed to Obama that bin Laden had been tentatively identified. About three hours later, they said there was a "high probability" they had gotten their man — a conclusion they would later solidify by matching DNA taken from the corpse to that of a bin Laden relative.
Obama called his predecessor, President George W. Bush, to inform him of the raid's success. He then prepared to address the nation, going live on the air at 11:35 p.m. to announce, "The United States has conducted an operation that killed Osama bin Laden, the leader of al-Qaida, and a terrorist who's responsible for the murder of thousands of innocent men, women and children."
One more task remained: disposing of the body. Administration officials said unidentified nations they approached about taking custody of the remains declined.
Bin Laden's body was flown to the U.S. aircraft carrier Carl Vinson in the North Arabian Sea, where it was washed in accordance with Islamic custom, wrapped in a white sheet and then placed inside a weighted bag, a senior defense official said. A military officer read religious rites — translated into Arabic.
With that, the body of the man who once vowed that "the dream to kill me will never be completed" was placed on a board, tipped up and eased into the sea.
Staff writer Richard Halicks contributed to this article. Sources: National Journal, New York Times, Washington Post, Associated Press, Guardian, Wall Street Journal, BBC, POLITICO, Fox News, CNN, Al Jazeera English, White House
