In The Fourth Monkey, violence and a distorted moral code are presented not as innate qualities but as learned behaviors passed down through a corrupt family environment. The novel explores this inheritance primarily through the diary of the killer, Anson Bishop, which details an upbringing where monstrous acts are framed as loving, educational lessons. This challenges the idea of a clear line between victim and perpetrator, suggesting that evil is often a cultivated legacy. Bishop’s diary portrays his childhood as a perverse version of a loving home, where his parents teach him their violent ideology. His father’s lectures on the “Four Monkeys” serve as a moral framework, justifying torture and murder as necessary acts to punish evil. The narrator recalls how his mother, after brutally attacking a neighbor, explained she was “trying to slice the evil out of him” (106). These events are not presented as traumatic but as formative. The torture and murder of Simon Carter becomes a practical lesson, and Bishop’s participation is a rite of passage.

Much of the diary narrator’s moral degradation as a child is symbolically mimicked through the dead cat that he keeps by the lake. Tempted by violent fantasies, he kills a cat and keeps it in a secret spot so that he can observe its decomposition. As the diary goes on, following the heightened violence against the Carters and the dissolution of his family unit through his mother’s plotting, the animal decomposes further and further. Finally, after his father is shot, his mother tells him to find an object they need, supposedly hidden under the cat’s corpse. Instead, he finds his knife, which his mother stole and placed there as a deception to lead him away while she and her accomplices escaped. This represents how a living creature is slowly pared away to an unfeeling object with only violence hidden beneath, much like the 4MK killer by the end of his diary.

As an adult, Bishop fully internalizes and perpetuates his parents’ worldview, becoming the killer they groomed him to be. His meticulous methods and moralistic justifications for his crimes directly mirror the lessons of his youth. The diary itself is an extension of this legacy. It is not merely a confession but an act of teaching, an attempt to pass on the knowledge his parents imparted to him. The opening lines invite Detective Porter to “understand what I have done” (xiii), positioning the reader as a new student in this dark curriculum. By framing Bishop as both a product of his upbringing and a perpetrator of horrific crimes, Barker illustrates a cyclical nature of violence. The novel posits that criminals are not simply born but are meticulously made, often within the very family structure meant to provide love and moral guidance.