Mortelle ecosse (POLICIER)

The suspense kept me on edge throughout, but I wonder what techniques or details he uses to create such a gritty, immersive atmosphere.

The detectives aren’t always clear-cut heroes, which made me question what justice really means in this story. How did others interpret their choices?

The gritty, often bleak environment added so much to the tone. I'm curious whether the author based it on real locations or created a fictional world to serve the story.