CNN) -- Osama bin Laden's death marked the end of an era for U.S. investigators, who searched remote villages and mountain caves in a far-reaching manhunt for the al Qaeda leader.

Their search, which lasted more than a decade, ended early Monday in Pakistan (Sunday night in the U.S.), when a small U.S. team raided a heavily guarded hideout in Pakistan and killed him.

The key break in the case came in August, when senior Obama administration officials say U.S. intelligence homed in on a $1 million compound in an affluent area north of Islamabad where one of bin Laden's couriers lived.

But the trail that eventually led the United States to bin Laden began years ago, the officials said.

After years of thwarted searches and dead ends, finding the elusive bin Laden had become "America's most vexing intelligence problem," one senior Obama administration official told reporters in a background briefing in Washington early Monday.

COMMENT
the U.S have killed osama bin laden they said that its the end of an era but we dont know maybe theres someone even more bad than him thet is waiting to reveal but we dont know what will happen on this days to kill bin laden there was a lot of strategy planned and a huge inversion to find him I think that its a good think but thy havent the power to decide if someone deserves to die.