Geophysical monitoring of simulated homicide burials for forensic investigations

Abstract

Finding hidden bodies, believed to have been murdered and buried, is problematic, expensive in terms of human resource and currently has low success rates for law enforcement agencies. Here we present, for the first time, ten years of multidisciplinary geophysical monitoring of simulated clandestine graves using animal analogues. Results will provide forensic search teams with crucial information on optimal detection techniques, equipment configuration and datasets for comparison to active and unsolved cold case searches. Electrical Resistivity (ER) surveys showed a naked burial produced large, low-resistivity anomalies for up to four years, but then the body became difficult to image. A wrapped burial had consistent small, high-resistivity anomalies for four years, then large high-resistivity anomalies until the survey period end. Ground Penetrating Radar (GPR) 110–900 MHz surveys showed the wrapped burial could be detected throughout. 225 MHz GPR data was optimal, but the naked burial was poorly imaged after six years. Results suggested conducting both ER and GPR surveys if the burial style was unknown when searching for interred remains. Surveys in winter and spring produced the best datasets, and, as post-burial time increases, surveying in these seasons became increasingly important. This multidisciplinary study provides critical new insights for law enforcement and families of the disappeared worldwide.