title: Investigative Interviewing, Spatial Memory and Hiding Behaviour in Missing Body Homicide Cases
Creators: name: Ryan, Nathan C
Publisher: name: Griffith University
Year: 2021
Subjects: subject: Missing body
subject: homicide cases
subject: homicide investigations

description: Missing body homicide cases are rare and often high profile. In some cases where it has been determined that a homicide has been committed, but no body has been found, there are co-operative suspects or perpetrators who attempt to provide the location of the victim’s remains but are unable to give accurate information due to the length of time between hiding the body and attempting to retrieve it, or issues when encoding the memory such as being under the influence of drugs and/or alcohol. One such case is the death of Matthew Leveson in Australia, who was buried in a tract of bushland by his partner. During a coroner’s inquiry into the death several years later, the perpetrator, Michael Atkins, was compelled to disclose the location of Matthew’s remains without the risk of prosecution, essentially removing any logical reason for deception. Police investigators took Atkins to the proposed deposition site on three separate occasions to identify possible locations and excavated and sieved 7500 square meters of bushland. It was not until the last hour, of the last day, of the final search attempt, that Matthew’s body was found approximately 30m from one of the potential deposition sites identified by Atkins. In cases such as this, the way police gather and use information to locate the victim’s remains is critical to the outcome of the case. Improving the spatial recall of the perpetrator and understanding some of the patterns of behaviour that are used when hiding a victim’s remains could reduce the time and cost of search attempts, as well as improving the probability of locating the remains. This thesis presents a body of research that expands on the limited literature of missing body homicide investigations. Study 1 (Chapter 2) reports the findings of 11 semi-structured interviews with a highly experienced sample of homicide investigators with direct experience in missing body homicide cases or other applicable cases. Investigators were asked about their critical decision points, and how interviews in these cases should be conducted. Four main themes were identified from the interviews. These were; (a) establishing rapport; (b) strategies for gaining information about the site location; (c) strategies for checking suspect veracity; and, (d) impediments to the interview process. Further, the information provided by investigators, revealed an absence of a clear strategy for interviewing on-site. This finding was the inspiration for study 2. Study 2 (Chapter 3) used an experimental research design to test the effect of the Enhanced Cognitive Interview (ECI) on the spatial memory retrieval of participants in a real-world hiding task. The practical impediments identified in study 1, such as the mnemonics of the Enhanced Cognitive Interview that can and cannot be applied in practice within a missing body homicide investigation, were used to create an abbreviated version of that might be applied in an on-site interview when searching for the victim’s remains. Participants were required to hide a sack in a tract of bushland using a mock homicide scenario. Next participants were required to return to the same tract of bushland approximately 30 days later and were randomly assigned to either the abbreviated ECI or a free recall condition. The results of this study indicated that there was no significant difference between the ECI and free recall condition with participants’ accuracy in locating the hidden bag. However, the ECI generated significantly more information about environmental details, such as landmarks. This study provides an evidence-based interview strategy for practitioners to apply on-site in a missing body homicide case that generates valuable detail that many improve the outcomes of search attempts. Study3 (Chapter 4) examined the hiding behaviours of male and female participants in a bushland setting during a mock homicide scenario. This study found that participants tended to hide their objects in similar ways to actual perpetrators. Further, distinct patterns of hiding behaviours were found with female participants tending to exit the pathway at non-random points. Further, there were differences between males and females on the distance travelled to dispose of their object, with females travelling significantly less distance than males. This study adds to the existing research regarding the way humans hide objects, particularly in bushland. Further, it provides insight into the hiding behaviours of females, who are not represented in body disposal research. Finally, this study begins to fill a gap between the field research and laboratory studies on hiding behaviours by using a real-world naturalistic setting. Together, these three studies provide a significant contribution to the literature on missing body homicide investigations and provides homicide investigators with an evidence base to inform important investigative decisions, particularly in the field of investigative interviewing. Further, investigators who may be approaching these rare cases now have access to the expansive knowledge of experienced homicide investigators who have identified the challenges faced when approaching a missing body homicide case, and provided some practical solutions, an empirical evidence base for an onsite investigative interviewing strategy through an experimental study and valuable information regarding the hiding strategies employed by participants when faced with some of the practical constraints found in real homicide cases. This thesis contributes to the advancement of knowledge in both a theoretical and practical way with its focus on synthesising the literature on spatial memory, hiding behaviours, and investigative interviewing within the practical challenges faced by practitioners. This thesis concludes with a synthesis of the literature, limitations of the current research and some suggestions for future research.