D. A. Peterson

D. A. Peterson is a prosecutor drawn into the FBI's behavioral science work almost against his better judgment. Precise, cautious, and allergic to anything that smells like guesswork, he wants convictions that will survive appeal, not theories that sound impressive in a briefing room but collapse under cross-examination.

He functions as the show's reality check, the voice asking whether profiling is science or storytelling dressed up as science. Dashiell Eaves plays him dry and unimpressed rather than hostile, which makes his skepticism land harder — he's not the villain doubting the heroes, he's the professional whose job depends on getting it right.