AUSTIN, Texas -- When he left office in January 2009, President George W. Bush knew he was leaving behind what he would later describe as "unfinished business" -- tracking down Osama bin Laden.

"I wanted badly to bring bin Laden to justice," Bush wrote in his autobiography 'Decision Points.' "The fact that we did not ranks among my great regrets."

Although that mission was ultimately accomplished by Bush's successor, the former president and members of his administration basked in salutes of shared triumph Monday after President Barack Obama's stunning weekend announcement that U.S. forces had killed the elusive terrorist mastermind.

From the tortured minutes just after the Sept. 11, 2001, attacks until Bush left the White House to return home to Texas, the hunt for bin Laden was a daily objective throughout much of the Republican administration, former Bush officials said Monday.

Former top White House aide Karen Hughes, one of Bush's closest confidantes, remembered that Bush kept a list of al-Qaida leaders in his desk drawer "just to remind him of his focus to find them and bring them to justice."

Hughes, who is now the Austin-based global vice president for Burson-Marsteller, a public relations and communications firm, said she sent Bush an email shortly after hearing the news Sunday night. Describing her own reactions, she said she felt "some relief, some satisfaction, but mostly an enormous feeling of pride and gratitude for the intelligence officers who literally dedicated the last 10 years to bringing this about."

The attacks that took 3,000 lives on America's East Coast helped define much of Bush's presidency and put the nation into a war footing that has extended into the Obama presidency with the continuation of combat troops in Afghanistan, which once served as bin Laden's base of operations.

Hughes and other administration officials said the hunt for bin Laden manifested itself in various ways in the Bush administration, from the president's daily CIA briefings in the White House to the scrubbing of minute fragments of information by the intelligence community.

The search was not without its flaws. Some scholars and administration critics contend that U.S. military operatives muffed an early opportunity to corral bin Laden in the caves of Tora Bora in Afghanistan. Bush also was sometimes accused of diverting his attention away from bin Laden to focus on the war in Iraq and for being too soft in his dealings with officials in Pakistan, the country where the terrorist leader was ultimately located.

But those engaged in the task -- including Bush himself -- say their commitment never wavered.