The novel argues that a state combating revolutionary terror adopts the terrorists' own methods (provocateurs, planted agents, extrajudicial killing), so the hunter and the hunted converge in tactics and morality. The security apparatus becomes indistinguishable from the enemy it claims to oppose.
A single individual secretly serving both the revolutionaries and the secret police can steer events on both sides, manufacturing crises to prove his own value to each master. His power comes not from either allegiance but from being the undisclosed link between two opposed systems.
Fandorin solves the case by asking who gains from a crime rather than who physically committed it, treating the visible perpetrator as a tool and the hidden beneficiary as the real agent. This reframes a murder as a transaction whose author is whoever the outcome serves.