The face of death

Horrific murders committed by a serial killer; The police are surprised at one of the crime scenes with the image of a person wearing a black mask and leaving a message requesting that a specific officer investigate the case, otherwise he will not stop killing. On the second part, the "Logic of the Dead" appears, following everything that happens to decide to turn the events upside down.Why does the killer insist on choosing that particular officer? And will the officer be able to stop this madman? What is the secret behind (Logic of the Dead)?