OUAGADOUGOU, Burkina Faso—The images that circulated on social media following last month's bloody attack on the village of Solhan, in northeastern Burkina Faso, weren't as gory as those that are often shared online after towns have been hit by armed groups. But even in a country where such killings are a near-daily occurrence, there was something about the photographs—showing dozens of bodies wrapped in woven prayer mats and piled into a...
