Callas, France — The gate opened slowly, offering a glimpse of overgrown gardens, weathered statues of naked mythical figures and a large white house with pale green shutters. We tried to soak it in quickly, not knowing whether the gate would snap shut as it had once before. At the top of stone stairs leading to the house stood an elderly blonde woman we recognized right away: Maria Duval, the woman we had been investigating for more than two years. We had never before laid eyes on her. But we’d seen her face many times.