ABUJA, Nigeria—Masturah Musa kneads a ball of halawa with her fingers. As it begins to soften, she spreads the sticky caramel across her customer’s leg, then pulls it upward.

Operation Condor, a France and U.S.-endorsed campaign of torture in South America, is long over. But the brutality it wrought still echoes today.

Obituaries of Gen. Efraín Ríos Montt only tell part of the story. Here's the rest.