Forensic Use of Ground Penetrating Radar: Casework
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Forensic Use of Ground Penetrating Radar: Casework


ue to the popularity of TV shows such as CSI, Law and Order, Forensic Files, and others, the term “forensic science” has become somewhat of a household phrase. As a result, most people have a general understanding of what forensic science is – often used interchangeably with crime scene investigation – but in reality, “forensic science” is more in depth than it may appear on the surface. More correctly defined as “the forensic sciences”, this phrase refers to the application of any field of science to legal proceedings, particularly those relating to criminal matters. Common fields of study include forensic anthropologists that study bones, forensic pathologists that study diseases and the human body, forensic entomologists that study insects, and forensic chemists that perform toxicology and drug analyses, but there are myriad additional subspecialties within the forensic sciences. One particularly unique subspeciality is that of forensic taphonomy. Not as familiar with this phrase as the others previously mentioned? Don’t worry! That is to be expected since forensic taphonomy isn’t as popular of a science as some. In fact, forensic taphonomy is not its own field of science, but rather, a subfield of forensic anthropology that focuses on the study of human decomposition – often in the context of burial sites – and the relationship between the process of decomposition and the environment.

The basic premise of forensic taphonomy is that the process of decomposition itself will affect the surrounding environment in which a body is decomposing and conversely, the environment will affect the process of decomposition. The relationship between the two can yield important information about the circumstances at, around, and after the death event which can be critical for a medicolegal death investigation. This is especially important if a body has been buried because investigators will rely on environmental clues to help locate the grave. In cases such as these, ground penetrating radar is an immense asset to a death investigation as it can help locate a clandestine gravesite.

In the same way that certain presumptive tests can be used to quickly determine if a reddish-brown substance is actually blood before conducting more in-depth analyses of it, ground penetrating radar can be used as a sort of presumptive test for a suspected gravesite before undertaking a full-scale excavation.

Often, in the context of a medicolegal death investigation, investigators are operating based on tips that may be vague or unreliable. An informant may provide information such as “I think the body is buried somewhere out in the field behind the high school.” While this certainly provides a good starting point for a search, it is not practical to dig up an entire field in search of a body that an informant only “thinks” might be there. This is where ground penetrating radar becomes vital. A well-trained GPR operator can conduct a search of the area in question and identify more specific areas of interest based on the results of the scan (Figure 1).

Figure 1
GPR forensic data collection with a FINDAR® system.

Unlike what is typically shown in the television-depicted use of GPR, an investigator will not be able to tell exactly what is buried beneath the surface; GPR doesn’t work as an underground X-ray machine. However, it can provide information on anomalies beneath the surface that are likely to be of forensic significance such as a body, a weapon, or other items of evidence (Figure 2).

Figure 2
GPR cross-sectional data showing an anomaly and disturbed soil that may be a clandestine grave.

Based on the information provided by the GPR, investigators can then dig test pits in these areas of interest to determine what is actually beneath the surface and whether or not a full-scale excavation is necessary (Figure 3).

Figure 3
Excavation of a possible clandestine grave site based on GPR survey results.

The use of GPR in this way can save a tremendous amount of time and resources by allowing investigators to target their searches to the areas that are most likely to yield promising results.

In future articles, I will discuss the application of GPR to unique fields within forensics, such as education and research.

Story courtesy of PhD. Lerah Sutton, PhD
Director – Forensic Medicine Educational Program
Assistant Director – Maples Center for Forensic Medicine
University of Florida College of Medicine

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