AP Photo

In late February 2004, Janjaweed militias and Sudanese government forces waged a three-day, coordinated assault on Tawila, a village in northern Darfur. Government aircrafts destroyed buildings, while the Janjaweed broke into a girls’ boarding school, forced the students to strip naked at gunpoint, and then gang-raped and abducted many of them. Video footage shows fly-covered corpses strewn among the village's smoldering ruins. And giving orders and distributing weapons during the siege, eyewitnesses say, was Sheikh Musa Hilal.

Hilal's name looms large on the list of perpetrators who’ve committed atrocities in Darfur since violence erupted there in 2003. At Khartoum's request, he organized the Janjaweed, predominantly Arab militias that have operated hand-in-glove...