From the NY Times:
WASHINGTON — 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 35 miles north of the Pakistani capital, close to one of the hubs of American counterterrorism 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 by American military and intelligence operatives that ended in the death of Bin Laden on Sunday and concluded one of history’s most extensive and frustrating manhunts.