ISLAMABAD, Pakistan – A U.S. drone strike in northwest Pakistan has killed al-Qaida’s second in command, officials from both countries confirmed Tuesday, the most significant victory so far in the controversial bombing campaign and the biggest setback to the terror network since the death of Osama bin Laden.

Abu Yahya al-Libi was considered a media-savvy, charismatic leader with religious credentials who was presiding over the transformation of a secretive group based in Pakistan and Afghanistan into a global movement aimed at winning converts – and potential attackers – from Somalia to the Philippines.

This was not the first time the U.S. had al-Libi in its sights: He was originally captured a decade ago and held by American forces at Bagram Air Field in Afghanistan until he escaped in 2005 in an embarrassing security breach. Soon thereafter, he began appearing in videos in which he talked about the lessons he learned while watching his captors.