After years of dead ends and promising leads gone cold, the big break came last August.
A trusted courier of Osama bin Laden?s whom American spies had been hunting for years was finally located in a compound about 60 km north of the Pakistani capital, close to one of the hubs of American counter-terrorism operations. The property was so secure, so large, that American officials guessed it was built to hide someone far more important than a mere courier.
What followed was eight months of painstaking intelligence work, culminating in a helicopter assault that ended in the death of Bin Laden on Sunday.
For nearly a decade, American military and intelligence forces had chased the spectre of bin Laden through Pakistan and Afghanistan. The real breakthrough came when they finally figured out the name and location of bin Laden?s most trusted courier, whom the Qaida chief appeared to rely on to maintain contacts with the outside world.
Detainees at the prison at Guantanamo Bay, Cuba, had given the courier?s pseudonym to interrogators and said the man was a protege of Khalid Shaikh Mohammed, the mastermind of the 9/11 attacks. American intelligence officials said on Sunday night they finally learned the courier?s real name four years ago, but that it took another two years for them to learn the general region where he operated.
Still, it was not until August when they tracked him to the compound in Abbottabad. CIA analysts spent the next several weeks examining satellite photos and intelligence reports to determine who might be living at the compound, and a senior administration official said that by September the CIA had determined there was a ?strong possibility? that bin Laden himself was hiding there. On March 14, US President Barack Obama held the first of what would be five national security meetings in the course of the next six weeks to go over plans for the operation.