“What still puzzles me about this case is that we have zero leads on Aiden Reeves or on where the hell these tapes even came from,” Special Agent Carla Ramirez said, leaning back in her chair with her arms crossed tight over her chest. The fluorescent lights in the FBI’s New York field office conference room buzzed overhead, throwing stark shadows across the cluttered table: towering case files, grainy stills from security footage, cold coffee cups, and a laptop frozen on a blurred frame that no one wanted to look at too long.

The room carried that particular heaviness that settled in when agents spent too many hours staring pure...