What happened in the takedown of Osama bin Laden was the pinnacle of years of intelligence work which included the CIA, the NGA, and the NSA, according to White House senior administration officials' reports which chronicle the details below:
It began with the CIA following leads on those bin Laden considered his closest. Detainees post-9/11 gave information on individuals who had been directly aiding bin Laden and his deputy after they left Afghanistan.
The detainees turned over one courier's nickname who featured a repulsive resume: he was the student of Khalid Sheikh Mohammed and an assistant to Al Qaeda's former number 3, Abu Faraj al-Libbi. Even more important, this courier was one of few trusted by bin Laden and possibly was living with him and protecting him.
For years, however, the courier's real name and location remained a secret from the U.S. Then, four years ago, his name was discovered. Two years later, the U.S. also discovered his areas of operation in Pakistan, though his living quarters eluded U.S. intel, which in itself was a further indication to the U.S. that they were pursuing something worthwhile.
In August 2010, that home was finally discovered. It's interesting to note that the White House report describes the area as somewhat affluent and a place with much retired military. Khalid Sheikh Mohammed and Al Qaeda's #3 were also captured in settled areas of the country. The sight of the 3-story, $1 million living residence surprised the U.S.: it was on a large area of land, approximately eight times larger than the other residences there. It had 12 to 18-foot walls with barbed wire perched on top. It also had internal wall sections. Those who lived there reportedly burned their trash (unlike their neighbors, who put the trash out to be picked up), and the compound's entrances were two security gates. The 3rd floor terrace had a 7-foot privacy wall. It also had no internet or telephone service connected. The courier (and his brother) did not have an "explainable source of wealth." At the time it was built (2005), it was relatively isolated, but other homes have since built up close by.
Then U.S. intelligence discovered there was another family living in the compound in addition to those of the two brothers. This family fit the description consistent with that which the U.S. expected would be accompanying bin Laden.
But the U.S. wanted to be sure, so it conducted red team exercises and analyzed the intel from every angle. The results consistently pointed to the secret inside the compound being Osama bin Laden.
Meanwhile, the operation to take out bin Laden had been under preparation for months, with regular briefings for President Obama. In September of last year (approximately a month after the compound location was discovered), the president and the CIA began to work "on a set of assessments" that resulted in the U.S.'s belief that bin Laden could indeed be in the compound. By mid-February, the intelligence basis justified plotting a course of action for getting bin Laden at that location. From March 14th to April 29th, the president chaired at least five National Security Council meetings on the mission. He gave the final order for the now famous mission on the morning of April 29th (at least one American who probably wasn't watching the royal wedding live).
The mission that took bin Laden out was a collaboration between intelligence agencies and the U.S. military. A small U.S. team made a helicopter raid on the compound. The White House report details the dangers associated with the task: high walls, security setup, the relatively settled location, and it being only 35 miles north of Islamabad.
It took the U.S. team under 40 minutes in the compound to do its work. The only loss the U.S. sustained was one of the two helicopters used in the raid -- the crew members were able to board the remaining helicopter to get out. The total death toll was four adult males killed -- bin Laden, and supposedly the two couriers and bin Laden's son-- and one woman, who one of the men used as a human shield. Two women were also injured in the attack.
Bin Laden, who resisted the assault force, met his death in a firefight by the most well-trained military in the world -- a testament to the great country he tried so hard to destroy.