Criminal Profiling and classification of serial killers has been an expanding area of research for decades. Recent research has called into question the accuracy and utility of these systems, and calls for further research and development. This study aims to use the Serial Killer Database (SKDB) to examine and classify differences in criminal behavior between serial killers who act alone versus those who act in pairs, groups, or teams. The specific aim of this study is to examine whether there are significant differences between Solo Serial Killers and Team Serial Killers in the Number of Victims, Length of Career, Method of Killing, Motive for Killing, and Relationship to the Victim. From the SKDB, a total of 4,865 serial killers will be included in either the Solo Killer (n=3,806) or the Team Killer (n=1,059) groups. Using cluster analysis, differences in the above variables were examined across groups, in an effort to detect meaningful and predictable patterns that may differentiate the two groups. The purpose of this study was to add to the expanding research on serial killer typologies and classifications, and to provide support for furthering the specificity of existing typologies to include differentiating between Solo and Team Killers
