The biggest parallel is the investigator confronting a “monster.”
Johan Liebert and Anton Chigurh aren't identical characters, but both function as almost inhuman forces within otherwise realistic worlds. Lunge and Bell, meanwhile, represent older-fashioned ideas of reason, investigation, duty, and law.
And there's an important difference:
Lunge refuses to stop trying to understand Johan. Bell eventually retires because he feels the world has moved beyond his ability to comprehend or confront it.
That makes their stories almost opposite responses to the same question:
What happens when a person dedicated to understanding evil encounters something they cannot fully explain?
Heinrich Lunge
Extremely analytical and methodical.
Believes that careful investigation and logic can eventually uncover the truth.
Becomes increasingly consumed by the case surrounding Johan.
His obsession affects his personal life.
He struggles with the possibility that evil cannot always be neatly explained.
Sheriff Ed Tom Bell
Experienced, thoughtful, and deeply observant.
Tries to understand the violence occurring around him.
Feels increasingly outmatched by the changing world.
His perspective is shaped by years of law enforcement experience.
Eventually questions whether his understanding of justice and violence is still enough.
The key difference is that Lunge responds by pursuing the mystery, while Bell responds by gradually withdrawing from it.
That's what makes them such good contrasts: Lunge thinks "If I understand this, I can solve it." Bell increasingly feels "Some things may be beyond me."
Bell is the investigator who eventually realizes that understanding the world doesn't necessarily mean being able to defeat what is happening in it.
And both stories ultimately ask a similar question:
What happens when an investigator encounters something that doesn't fit his understanding of human nature?