Traits of detective fiction:
1. Hero must be an outsider who both fails at making money and being popular, and also refuses to engage in conventional altruism.
2. Hero must have some moral compass or motivation to a higher moral standard: past trauma, belief in higher power, belief in morality, Nietzsche will to beauty.
3. Hero must persist in vision unrecognized by others.
4. Hero must be opposed by normal people and even beaten or arrested by the official good guys, who only later recognize his or her good guy status.
5. Most people must find hero's quest baffling as it is inconsequential to material success.
6. Hero must confront the bad guys and explain himself or herself through the confession of the bad guys.
Very similar to metal, really... outsider art of a higher moral standard that, in metal's case, transcends humanism.