Soon after coming to office, President Obama made it clear that killing or capturing Osama bin Laden was one of his highest national security priorities.
But it wasn't until last summer that intelligence officials caught a break in their pursuit.
In September 2010, the CIA presented Obama with a set of assessments that indicated bin Laden could be hiding in a compound in northwest Pakistan. Starting in mid-March, the president convened at least nine National Security Council meetings to discuss the intelligence suggesting bin Laden may be hiding out virtually in plain sight.
The CIA developed its theory through leads from individuals in bin Laden's inner circle and other captured fighters following September 11. Intelligence officials were repeatedly told about one courier working for bin Laden as someone that America's most wanted man deeply trusted.
The detainees provided U.S. officials the courier's nickname and identified him as a protégé of Khalid Sheikh Mohammed and a trusted assistant of Abu Faraj al-Libbi, once al-Qaida's third-highest-ranking official. (He was captured in 2005.)
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The president finally gave the order for the operation to pursue bin Laden on Friday morning--just before he departed for Alabama to visit areas ravaged by last week's tornadoes, a senior administration official said.
Early Sunday morning in Pakistan, the strike began.
By 1 p.m. in Washington, top advisers had gathered at the White House. Around 2 p.m., Obama huddled with them to review final preparations for the operation. He returned to the Situation Room at 3:32 p.m. for another update, and by 3:50 he was given word that bin Laden was "tentatively identified" as among those killed in the operation. At 7 p.m., Obama was told it was a "high probability" that it was, indeed, bin Laden.
The entire operation took just 40 minutes and involved a small U.S. team, a senior administration official said.
In addition to bin Laden, four others were killed in the strike on the compound in an affluent suburb about 35 miles outside of Islamabad: an adult son of bin Laden, two of bin Laden's couriers, and a woman who an administration official said was used as a human shield.
Administration officials offered scant details about how bin Laden conducted himself in his final moments, only saying that he was felled in a firefight.
No Americans were killed in the operation, which was kept secret from the Pakistani government until after it was completed. But an administration official said that a helicopter was lost in the operation.
Before announcing the news that bin Laden had been killed, Obama called former presidents Bill Clinton and George W. Bush to deliver the news.
By the time Obama stepped to the podium, hundreds had gathered outside the White House to celebrate the news.