The face of death

Horrific murders committed by a serial killer; Then the police were surprised at one of the crime scenes with a picture of a person wearing a black mask and leaving a message requesting that a specific officer investigate the case, otherwise he would not stop killing. On the second part, “the logic of the dead” appears as he follows everything that happens to decide to turn the events upside down.

Why does the killer insist on choosing that particular officer? Will the officer be able to stop this madman? What is the secret behind (Logic of the Dead)?