Cooling-off periods and serial homicide: A case study approach to analysing behaviour between murders

Understanding cooling-off periods is an important step towards conceptualising life course events of serial killers, between their murders. Analysing the behaviours of serial killers between each homicide may give insight into when or if they will kill again, as well as informing definition criteria of what constitutes a serial killer as opposed to mass or spree killing. Research in this area typically analyses aggregate, large-scale data; however, this can often miss the idiosyncratic, specific details that are needed in real-word cases. To provide a more detailed account, an in-depth case study approach was taken to analyse the behaviours of Dennis Rader and Lonnie Franklin Jr., two well-known American serial killers, throughout their criminal career and identify patterns in their dormancy periods between murders. The analysis highlights that trophy-taking, the use of letters to communicate with the public, and offending-orientated fantasy may increase the length of a cooling-off period by suppressing homicidal urges. In contrast, the need for homicidal control may influence the effectiveness of such suppressing factors over time. The present research suggests that life-events can influence intervals between murders, even acting as a catalyst at times, which may help legal decision making.