Setting the mood and tone in crime fiction should be done up front.
The opening passages tell the reader the type of world they are entering and what they can expect.
The opening might give character insights, setting, and the basics of the crime—and reveal the voice.
What’s the difference between mood and tone?
Tone is the author’s attitude
Mood is the atmosphere and emotion the author creates
So, tone reflects the author’s attitude while mood is how the reader feels about the story.
Mood and Tone can be revealed through word choice, sentence structure, formal vs informal writing, point of view, objective vs subjective, rhythm, setting, action, dialog, voice—in short, all the tools of storytelling.
Like other fiction, mood and tone in crime stories runs the gamut—dark, light, noir, cozy, suspenseful, humorous, quirky, creepy, supernatural, you name it.