Serial Murder Patterns in Unsolved Cases

Although research has been done on serial murder cases in general, unsolved serial murder cases have rarely been investigated. Offenders who elude identification offer little evidence for clearing cases. Thus, similarities among serial murder cases, and even more specifically among unsolved cases, need to be empirically explored to identify advantageous techniques as preventive measures against future serial murderers. This study includes two sets of data, one consisting of 399 solved and a second constituting 75 unsolved serial murder cases. In an attempt to differentiate unsolved from solved cases, five variables--rate of killing, vulnerability, body disposal, location of body disposal, and mobility--are used. Statistically significant results supporting the hypotheses are found for the first three variables. VioLit summary: OBJECTIVE: The purpose of this article by Mott was to examine variables in unsolved serial murder cases in order to identify preventative techniques. METHODOLOGY: The author used two sets of data, one archival, and the other collected by the author. The archival data consisted of 39 solved serial murder cases, collected between 1800 and 1995. The latter data were determined for inclusion when the same person committed at least three murders and a period of time (days or months) existed between murders. These data were collected from newspapers, crime encyclopedias, reference books, law enforcement files, and computer searches. The cases were coded according to the following crime scene and victim characteristics: rate of killing, offender's mobility, victims' vulnerability, presence of a body disposal site separate from the killing sit for victims, and body disposal sites (e.g., outdoors, indoors, both). Using discriminate analysis, the author compared the solved and unsolved cases, using the above variables. FINDINGS/DISCUSSION: In an effort to differentiate characteristics from solved and unsolved cases, the author proposed five hypotheses. The author found support for her first hypothesis, which was that offenders in the solved cases committed murder at a significantly higher rate than offenders in unsolved cases (T = -2.48). The author surmised that the time distance between the murder and the discovery of the victim is key to solving cases because of the attrition of material evidence. The second hypothesis, that more serial murderers that travel to some degree while killing will be clustered in the unsolved cases, was not supported by the data. Rather, the opposite was found; there were significantly more mobile killers in the solved cases. Hypothesis three stated that more unsolved cases will involve more vulnerable victims. Victim vulnerability was defined as victims who facilitate the crime (e.g., prostitutes or hitchhikers). The data supported this hypothesis. Hypothesis four predicted there would be more victims disposed of outdoors in unsolved cases than in solved cases. The data supported this hypothesis. Finally, the author hypothesized that there would be significant differences in terms of the number of crime scenes. That is, it was predicted that solved cases would more likely use fewer body-drop sites than unsolved cases. The author did not find support for this hypothesis. The motivating belief behind each of these hypotheses was that there is a direct relationship between the amount of evidence and the solvability of a case. The author found support for the following: (1) That offenders from unsolved cases take more time between murders, (2) That victims in unsolved cases were more vulnerable, (4) That the bodies of victims in unsolved cases were more often dumped outdoors, and (4) That solved cases more often contained offenders that were mobile. AUTHOR'S RECOMMENDATIONS: The author suggests that further studies examine the possibility of urbanization as a variable in exploring the mobility of murderers. The author also suggests more discriminatory investigative techniques that include a distinction between "modus operandi" (method by which the crime is committed) and "signature traits"(an act found associated with the crime, but isn't necessary to the crime). The author also urges studying serial murder using the feminist perspective. (CSPV Abstract - Copyright © 1992-2007 by the Center for the Study and Prevention of Violence, Institute of Behavioral Science, Regents of the University of Colorado) KW - Serial Homicide KW - Offense Characteristics KW - Homicide Trends and Patterns KW - Homicide Offender KW - Adult Homicide KW - Adult Offender KW - Adult Violence KW - 1800s KW - 1910s KW - 1920s KW - 1930s KW - 1940s KW - 1950s KW - 1960s KW - 1970s KW - 1980s KW - 1990s KW - 03-02