David Axe reports: At 3:00 in the morning on Sunday a 38-year-old U.S. Army staff sergeant reportedly sneaked out of a coalition outpost in the Panjwai district of Afghanistan’s Kandahar province, walked at least 500 yards to a cluster of home compounds known as khalats and began forcing open doors. Moving from khalat to khalat, the sergeant allegedly shot and killed at least 16 Afghan civilians, including nine children.

He covered some of the bodies with rugs, lit them on fire then strolled back towards the outpost. An American patrol, alerted by Afghan troops that had witnessed the alleged killer’s departure, intercepted the shooter and took him into custody. But the fallout from the Sunday killings could be greatest in the villages that are most vital to NATO’s endgame strategy.

The alleged killer, reportedly a veteran of three Iraq tours who deployed to Afghanistan for the first time in December, is now in military custody. His brutal crime, as yet unexplained, has stoked the political firestorm sparked when a U.S. officer accidentally sent several Muslim holy texts to a burn pit outside a U.S.-run prison two weeks ago. Rioting and shootings in the aftermath of the Koran burnings claimed the lives of scores of Afghans and six U.S. troops.

On Sunday, The New York Times reported hundreds of angry Afghans Afghan gathering outside the Panjwai outpost as Afghan President Hamid Karzai called the killings “inhuman” and “unforgivable.” More riots are likely as news of the murders spreads. “They really want justice,” Prince Ali Seraj, head of the National Coalition for Dialogue with the Tribes of Afghanistan, said of Afghans. The Taliban has vowed revenge.

The Army, the Pentagon, the NATO International Security Assistance Force and U.S. President Barack Obama all denounced Sunday’s killings and vowing to investigate. But the official apologies may be too late to save the decade-long NATO-Afghanistan alliance, already damaged by the Koran burnings, the 2010 “sport hunting” of Afghan civilians by rogue U.S. troops (reportedly from the same base as the alleged Panjwai killer), errant NATO air strikes that have killed thousands of innocent Afghans over the years plus countless minor acts of cultural cluelessness that have slowly poisoned relations between Afghans and their supposed foreign allies.

Disturbingly, it seems the alleged killer, though apparently not a Special Forces soldier himself, was working alongside U.S. commandos as they worked to establish ties with Panjwai’s elders. Special Forces are selected in part for their language skills and cultural sensitivity. During our February visit to a Special Forces “A Team” in Laghman province, east of Kabul, the commandos described many of the ways coalition troops purposefully or accidentally offend their Afghan counterparts.

AFP reports on a statement issued by the Taliban: “A large number from amongst the victims are innocent children, women and the elderly, martyred by the American barbarians who mercilessly robbed them of their precious lives and drenched their hands with their innocent blood,” the Taliban said.

“The American ‘terrorists’ want to come up with an excuse for the perpetrator of this inhumane crime by claiming that this immoral culprit was mentally ill.

“If the perpetrators of this massacre were in fact mentally ill then this testifies to yet another moral transgression by the American military because they are arming lunatics in Afghanistan who turn their weapons against the defenceless Afghans without giving a second thought.”