“On September 9, 2001, Osama bin Laden repaid [Taliban leader] Mullah [Mohammad] Omar for all his help in hosting al Qaeda and all the difficulty it had led to. In a brilliant operation, the al Qaeda organization killed Omar’s number-one enemy in Afghanistan, the military leader of the Northern Alliance, Ahmad Shah Massoud. …Bin Laden fully expected an American attack after 9/11 and wanted to remove the Northern Alliance’s leader and thus weaken it before any such retaliation might come.”
– Bruce Riedel, The Search for Al Qaeda, Pages 76-77