Timeline: Tip Leads U.S. to Usama Bin Laden

The tip that landed Usama bin Laden came to light in August. It was a “great lead,” a federal law enforcement source told Fox News.

Officials wouldn’t know how good it was until months later. After an exhaustive streak of intelligence gathering and high-level meetings, that tip resulted Sunday in the death of the world’s most wanted terrorist at U.S. hands.

Though President Obama gave only sparse details of the operation in his surprise address to the nation Sunday night, officials filled in the blanks where they could about the mission that brought to justice the man responsible for the Sept. 11, 2001, terror attacks and countless acts of violence around the world.

Though bin Laden was pursued throughout the George W. Bush administration, President Obama renewed the effort on June 2, 2009, when he signed a memo to CIA Director Leon Panetta ordering a “detailed operation plan” for finding and capturing bin Laden.

More than a year later, what Obama described as a “possible lead” came in. Senior administration officials said they had been tracking an Al Qaeda courier in bin Laden’s inner circle. Two years ago, the U.S. determined the areas in Pakistan where he operated. By August, they had determined the exact location in Abbottabad, Pakistan -- where bin Laden was apparently hiding out in a sprawling compound on the outskirts of town.

One U.S. official said the compound was built over a six-year period. The intelligence community, led by the CIA, concluded it was custom-built to house someone of bin Laden’s stature. It was enclosed by a high wall topped with barbed wire, and protected by two security gates.

Officials said that by February, they determined they would pursue the compound. This touched off a series of high-level meetings to develop a course of action.

According to one senior administration official, the president convened at least nine meetings with his top national security leaders. Those advisers met formally another five times, in addition to countless briefings among the National Security Council, CIA, Pentagon and Joint Chiefs of Staff. The president was actively involved at all levels, the official said.

The federal law enforcement source said that by last week, it seemed “this might be the real deal.”

The president must have felt the same way. At 8:20 a.m. on April 29, before he left for Alabama to survey storm damage, Obama authorized the operation to target bin Laden.

By Sunday, a “small team” of special operations forces was in Pakistan for the final mission. That mission was the all-day focus of national security staff.

According to one official, national security leaders were in the Situation Room since 1 p.m. Sunday. The rest of the afternoon went as follows:

At 2 p.m., Obama met with the team to review final preparations.

At 3:32 p.m., he returned to the Situation Room for an additional briefing.

At 3:50 p.m., he learned that bin Laden had been tentatively identified.

At 7:01 p.m., the president learned there was a “high probability” the target was bin Laden.

At 8:30 p.m., Obama received more briefings.

In Abbottabad, a senior U.S. defense official said the actual operation took place at 3:30 p.m. ET.

Officials said three adult men other than bin Laden were killed – one was believed to be bin Laden’s son, the others couriers. One woman was killed when she was used as a human shield and two other women were also injured, the officials said.

No Americans were killed, though the U.S. did lose a helicopter that went down due to mechanical failure. An official said the Pakistanis were not involved in the raid but helped provide information that led to it. Intelligence was also provided by detainees.