My obvious go-to would be the Lovecraftian tradition, which is also very racist in places (especially Lovecraft himself) but has a long history of telling mystery and investigative stories that don't involve the police.
Many stories in the Lovecraftian tradition are also sceptical of power, because their metaphor for power is not "heroic cop protecting us" but "evil corrupt cultist who'll summon a monster to kill you if you dare meddle in their schemes," and so it becomes a tale of the weak investigating the strong.
This isn't to say that the Lovecraftian tradition is always free of copaganda, and definitely not to say that it doesn't have problems of its own, of course.