Dexter's Final Cut by Jeff Lindsay

In this gripping installment, the story follows Dexter Morgan, a blood-spatter analyst with a dark secret as a vigilante serial killer, who becomes entangled in the world of Hollywood when a TV crew arrives in Miami to film a crime show. As Dexter is drawn into the glamorous yet dangerous world of show business, he finds himself working closely with a charismatic actor who is set to portray a character inspired by him. However, the lines between fiction and reality blur when a real-life threat emerges, forcing Dexter to confront new challenges and make difficult choices that could jeopardize his carefully constructed double life.