American officials said that Bin Laden was shot in the head after he tried to resist the assault force, and that one of his sons died with him.

For nearly a decade, American military and intelligence forces had chased the specter of Bin Laden through Pakistan and Afghanistan, once coming agonizingly close and losing him in a pitched battle at Tora Bora, in the mountains of eastern Afghanistan. As Obama administration officials described it, the real breakthrough came when they finally figured out the name and location of Bin Laden's most trusted courier, whom the Qaeda chief appeared to rely on to maintain contacts with the outside world.

Detainees at the prison at Guantánamo Bay, Cuba, had given the courier's pseudonym to American interrogators and said that the man was a protégé of Khalid Shaikh Mohammed, the confessed mastermind of the Sept. 11 attacks.

American intelligence officials said Sunday night that 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 that they tracked him to the compound in Abbottabad, a medium-sized city about an hour's drive north of Islamabad, the capital of Pakistan.