Does Le Tueur - La suite dans les idées need to be read after other books?

This volume is part of a longer graphic novel series, and while each installment offers a self-contained narrative arc, reading the preceding volumes will provide a richer understanding of the protagonist's evolving psychological state and the overarching story.

Is there a film adaptation of Le Tueur?

The graphic novel series, of which this book is a part, has been adapted into a film. The adaptation captures the dark, introspective tone of the source material.