A crime-solver in a Police Procedural who has killed and is The Atoner because of this. Their method of atoning is to catch other criminals. Because they can think like criminals, they are often better at this than the average cop.
Interestingly, this motive even applies to people whose killing was perfectly legal—people who served in the military, the FBI, or a spy agency. It also applies to [...] [tvtropes.org]