Revision with unchanged content. The phenomenon of serial murder is a crime characterised by a paucity of scientific information and an excess of popularised fictional material, contributing to the existence of inaccurate perceptions of serial murder. Available literature shows that research undertaken to determine the origin and the motivation behind serial homicide generally focuses on singular aspects of serial murder. In most cases the research is directed by theories of the psychoanalytic school, most notably that of Sigmund Freud. Another research approach is to develop models and methods for classifying serial killers. Despite the value of these models and the research that has been done the information they can provide is limited. In most cases the research and the models focus on singular aspects associated with the development of serial murderers, for example, the internal conflicts experienced by the child. The goal of this study is to determine which internal and external factors influence the personality development of the serial murderer. The research therefore focuses on how these factors were internalised and expressed behaviourally by the individual. To achieve this, the psychosocial perspective, which consisted of three psychological theories, was used to determine the role of both internal and external influences in the personality development of the individual.