Applications of the Ground‐Penetrating Radar Technique in the Detection and Delineation of Homicide Victims and Crime Scene Paraphernalia

During the spring, summer, and fall of 1997, ground penetrating radar profiles (radargrams) were acquired across a controlled/simulated homicide site near Rolla, Missouri. In this study, two deer carcasses were buried in separate trenches at depths of 0.53 meters and 0.58 meters, respectively. The trenches were excavated in compact, clay-rich alluvium. The carcasses were covered with less compacted alluvium. Two dimensional and three dimensional radargrams were acquired/constructed to optimize the interpretation of the data. We have evaluated the radar data acquired to date and have made several interesting interpretations/observations regarding the GPR signatures of the simulated homicide site and how they varied over time. More specifically, the radar signature of the trench is mostly a function of the fundamental differences (dielectric constant, velocity, and homogeneity) between the trench fill and in-situ soils. On the radar profiles, the undisturbed soil is characterized by laterally continuous reflection events. The trench/carcasses, in contrast, are characterized by a lack of laterally coherent reflection events. Over time, the signatures of the trenches have changed subtly. These changes are mostly attributed to compaction of the infill sediments and the decomposition of the deer carcasses. However, even after a period of seven months, the trenches remain relatively easy to differentiate from surrounding compact alluvium. In addition to the carcasses, a piece of metal the size of a handgun was buried. The corresponding anomaly on the radargram is a high amplitude, hyperbolic diffraction. The ground penetrating radar survey was successful. Over the seven month period, there was a notable change in the signature of the burial trench due to the decomposition of the bodies and the compaction of the trench fill. The surveys have established the ground penetrating radar technique as a useful tool in crime scene investigation for locating buried victims or evidence. INTRODUCTION Over a seven month period between May 1997 and November 1997, ground penetrating radar profiles were acquired across a controlled/simulated homicide burial site in northern Phelps County, Missouri (Figure 1). There were two objectives of the GPR surveys: (1) to establish the utility of the ground penetrating radar technique in the detection of buried bodies; (2) to establish the utility of the ground penetrating radar technique in the detection of buried crime paraphernalia (i.e. guns, knives, etc.).