Our study turns on the psychopathy revealed in the perverse criminal act of a serial sexual sadistic killer. Through a fictitious story, we dive into the real world of serial killers trying to understand the relevance of the fantasy connected to its way of being in the world as propellers of the ticket to the criminal act. A team of criminal investigators is joined with the intention of tracing the psychological profile of the criminal and proceeding to his capture with the resource of forensic sciences.