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