KANDAHAR, Afghanistan (AP) - The Taliban's most prominent military commander, a one-legged fighter who orchestrated an ethnic massacre and a rash of beheadings, was killed in a U.S.-led military operation in southern Afghanistan, officials said Sunday. Mullah Dadullah, a top lieutenant of Taliban leader Mullah Omar, was killed Saturday in the southern province of Helmand, said Said Ansari, the spokesman for Afghanistan's intelligence service. NATO confirmed his death, calling it "a serious blow" to the insurgency. Dadullah is one of the highest-ranking Taliban leaders killed since the fall of the hard-line regime following the U.S.-led invasion in 2001. His death...