Developing GPR surveys, data processing and interpretation techniques for criminal gravesites location

Abstract

The authors of this article investigated several issues concerning the testing of GPR surveying and the development of data processing methods for assisting in solving criminal activities as performed by the Investigative Committee of the Russian Federation. The work of governmental agencies along with forensic science are deeply based on using GPRs for detecting caches, crypts, conduits and saps, as well as buried explosives and bombs. This research contains general requirements for field work while surveying buried objects. The authors specify requirements for equipment to be used, how the processing of obtained materials should be managed, and, finally, what interpretation methods should be utilized. Various tools used in these specific areas were analyzed in cooperation with experts of the Russian Investigative Committee. This paper contains information on tests performed using an OKO-3 GPR device equipped with AB-400M3 aerial (central frequency 400 MHz), aimed at locating various objects, such as: metal sheet, metal pipe, concrete block, plastic tank filled with water, wooden log, and animal bones package (imitating organic burials). The article provides experimental material obtained and processed using these techniques. Measurements were tested over several stages. This type of monitoring not only allowed the tracing of signal alterations, but also the observation and analysis of potential changes to the soil's physical properties over time, depending on its density and moisture. This technique presupposes a GPR survey accomplished along an orthogonal observation grid with regular spacing between profiles, which allows 3D analysis of represented data. The authors suggest using a vast range of programming facilities for 3D-visualisation in programs of proprietary development. The results of these geophysical operations, in accordance with developed techniques, are represented in the object's location plan with determined depth and positioning. The investigated technique of using GPR surveying to uncover underground criminal activities, including explosives, proved to be highly successful and has thus been requested by law enforcement agencies.