Reading the Soil
Written by Bob Galvin   

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Not all crime cases provide the benefit of a smooth start and finish. Homicide cases in particular can stall part way into an investigation often because a body is missing and clues to its whereabouts seem elusive. When this happens, a forensic archaeologist sometimes may prove to be a valuable resource.

How is forensic archaeology applied in today’s law enforcement environment and what benefits can it yield in investigations that require this expertise?

Archaeology and Anthropology Intertwined

Archaeology and anthropology are sciences that are closely associated in many ways, and the terms frequently are used synonymously. Each science can be applied to forensic work. Archaeology explores past cultures, mostly ancient, by digging up, dating, and analyzing remains from particular eras, environments, and geographical regions. Anthropology also studies past civilizations, but strives to understand how the physical remains and artifacts of a civilization reflect behaviors and patterns of those civilizations. More specifically, anthropology studies human beings and in the U.S. is generally considered to include four sub-disciplines: archaeology (the study of human activity in the past), physical anthropology (the study of biological remains), cultural anthropology (the study of cultural variation in populations), and linguistic anthropology (the study of speech and written text).

Archaeologists Are “Detectives”

When crime investigations hit a snag due to lack of sufficient evidence or evidence that needs special expertise to find and then analyze, the forensic archaeologist may be able to help interpret events or even locate a body and other related evidence. Why? Because archaeologists are essentially detectives, just not the same as those who work in police departments. That’s the opinion of Michael Trinkley, a trained anthropologist and director of Chicora Foundation, Inc., Columbia, South Carolina, a non-profit foundation devoted to cemetery preservation throughout the Southeastern United States.

“Whether you’re digging a crime scene or something 5,000 years old, you’re a detective, you’re putting pieces of the past back together,” Trinkley asserts. Therefore, the questions of what activities went on at a crime scene and what they mean are important to ask.

If a law enforcement agency is seeking a forensic archaeologist, there are specific credentials this expert must have. These include an advanced degree in archaeology and demonstrated competence in applying techniques and standards of crime scene management and processing, what evidence must be kept, conditions under which it must be kept, chain of evidence, and the capability to testify in court.

“Reading The Soil” Helps Show How Crime Occurred

According to Trinkley, forensic archaeologists are not tapped often to help with crime cases. But when they are, their expertise can be invaluable.

“We read the soil,” Trinkley said, “and crime scenes are just more recent events of reading the soil. You can’t take a body out, bury it somewhere, and not find traces in the soil.

“The forensic archaeologist is focused on seeing those traces, interpreting them correctly, and excavating the remains in a way so that all evidence will be collected, and won’t be compromised,” Trinkley said. “The forensic archaeologist can reconstruct that crime scene so there’s a clear understanding of what occurred, when it occurred, and how it occurred.”

Technology Helps Interpret Event Details

Just like police detectives, archaeologists use technology to aid their training and investigative skills. One crucial piece of technology is a total station that proves quick and precise, for example, when mapping a grave site to be excavated. Trinkley recalled that one of his staff members attended a workshop to be trained on a Sokkia total station. “We were impressed with how precise it was, and how quickly information could be gathered and then transferred to paper,” Trinkley said. In fact, he noted, Sokkia’s strong interest in providing its technology to law enforcement over the past several years, tailoring it for reconstructionists and other users, plus making training available, were all big factors in Chicora’s choice of the Sokkia total station.

Trinkley uses a Sokkia 530R3 total station offering a 350m reflectorless range and ultra-narrow visible laser for pinpoint accuracy. The total station is connected via Bluetooth (for wireless data collection) to a pocket computer loaded with MapScenes Evidence Recorder Software. Data points collected are downloaded to the The CAD Zone, Inc.’s Crime Zone diagramming software.

How is the total station actually used for forensic archaeology? For example, when an archaeologist is trying to locate a large number of artifacts—whether these are bones scattered across a field, or fragments at an excavation—it is important to be able to locate these items quickly and precisely. “You can set up the total station quickly and sight directly to a couple of permanent points, such as a telephone pole, radio tower, or a building corner, without a target,” Trinkley said, “and then you can sight on each of those bones or pieces of evidence and very quickly identify precisely where they are and their relationship to one another.

“This gives us a huge savings in time and cost because we don’t need to send a person with a prism pole across the creek or through a jungle to get a target,” Trinkley added. “No technology will tell you what those bones or pieces of evidence mean. But first, you need to have the technology that will gather the data to be used for interpretation.”

Consequently, recording this information completely and accurately must be top priority. The total station helps accomplish this. “The goal is to have a map,” Trinkley said. Another ultimate goal is to have a map that the archaeologist can understand and, just as important, that can be understood by a jury. “The layman has to be convinced that this evidence really is what was out there on the ground, that it’s accurate—and then he has to understand what it means and be convinced of the accuracy,” Trinkley said. Once this has been accomplished, the forensic archaeologist can present a map of what he saw.

Beyond the total station, other tools forensic archaeologists use include metal detectors and GPS, a satellite navigation system with global coverage. However, Trinkley notes that GPS may not always be reliable due to locations without a clear view of the sky and the number of satellites a receiver can pick up, which can vary. The limitations of GPS can make this technology hard to use, especially since forensic archaeologists can be called to a crime scene on very short notice. Most Topcon and Sokkia total stations use GNSS (Global Navigation Satellite Systems) because they give higher accuracy and provide moving maps and information about location. Still another tool often used is ground penetrating radar which operates transmitting short pulses of electromagnetic energy into concrete, asphalt, hard soil, and other surfaces.

Focus on Dead Bodies

For Katherine Taylor, a forensic anthropologist for the King County (Wash.) Medical Examiner’s Office, the two disciplines of anthropology and archaeology blend together often. A forensic anthropologist takes skeletal anatomy and applies it to medicolegal death investigation, Taylor said. “But, in death investigation, you’re frequently asked to recover remains as well as analyze them. That’s where the archaeology comes in.” Crime scenes can have many types and forms. Taylor focuses on dead bodies, and is called upon to investigate many cold cases, which is why she is well versed in forensic anthropology and archaeology.

It is typical for Taylor to be called out to join law enforcement investigators as they search for a body. The search may be tied to a current case or a cold case. “We’re sure somebody killed the victim, but we don’t know where the victim is,” Taylor explained. “We’ve figured out the timeline and the body could be within a half-mile radius of the victim’s home. There is forensic archaeology involved in terms of reading and understanding the environment, but also understanding how perpetrators behave.”

Reconstructing an Event

Both Trinkley and Taylor agree that crime scene investigators and detectives are highly skilled at their jobs, yet they do not typically get trained in archaeology. So, for example, if a person has been buried and a hand is sticking out of the ground, law enforcement investigators may just pull the hand to get the victim out of the ground, whereas with forensic archaeology, it’s necessary to excavate that site meticulously because there is a lot of information available.

“We’re trying to reconstruct what happened, which is exactly what archaeologists are doing—trying to reconstruct past cultures,” Taylor said. “We’re trying to reconstruct a specific event, what happened to get a body in the ground, how many people were here, how deep is the body, what instruments were used to dig the grave, and did they leave anything behind, such as gum, hair, soda, tool marks, or did someone step into the grave and leave a footwear imprint.”

Type and Condition of Grave Important for Jury

A grave and how it has been prepared can speak volumes about the crime, method of murder, and the perpetrator. A deep burial, for example, can signal a possible premeditated murder. Taylor argues that a perpetrator rarely digs a grave big enough to accommodate the body. She would know after excavating 40 or 50 graves in her career. These are facts that are important for a jury to understand. “When I speak to a jury, I tell them a grave is not always what you think of, such as grave at a cemetery; it’s not six feet deep by two feet wide,” Taylor said.

Total Station Valuable for Marking Bones, Evidence

Like Trinkley, Taylor relies on a reconstructionist and the use of a total station to plot evidence points and then create a map for jurors to see. The map can show key evidence such as surface scatter, which may indicate animals have disturbed the grave and spread evidence all over the site.

“Typically, when we approach a scene, even if the body is buried, we’re still using a total station because we want to be able to map the location relative to the whole environment—how big the grave is, how deep it is,” Taylor said. The total station, she continued, allows the forensic archaeologist to have a very scientific way to completely reconstruct the crime scene. Much of the time the map or diagram produced from the total station’s plotted points will be in 2D. “But when you have buried bodies, the diagram needs to be in 3D because now you’re talking about depth,” Taylor said.

Taylor notes that a total station allows the user to choose whatever markers are desired. So, for example, she usually assigns all bones letter designations, while other evidence items will have numbers. “That way, I can quickly look at a map and tell exactly what’s bone,” Taylor said. “I’m not distracted by the numbers, and so I can see why a person is dispersed across a scene and why they are this way.”

Mapping a Burial

One case demonstrated how valuable the total station can be when reconstructing a scene and deciphering what happened and how. The crime scene was a grave containing the comingled bodies of two young people. The question was whether or not the bodies were buried together or apart. The answer would potentially reveal who buried the bodies.

“If these people were known by the perpetrator who saw them as individuals, he or she may have buried them separately,” Taylor said. “If somebody was throwing these bodies away, they were probably buried together.”

Taylor created a map with the total station evidence points and color-coded it (one different color for each body), then determined which bone went to which body. “I could look at the map and see that the colors were intermixed,” Taylor explained. “I had pieces of each person mixed together. That told me these people were completely comingled across the scene. This is where the total station was so critically important to me.”

Forensic archaeology is a powerful aid for selected crime investigations where recovering a body or related evidence can help add perspective and solve clues to a current case or a cold one. It involves asking a lot of key questions. According to Trinkley, applying forensic archaeology can have major consequences. “You must recognize that you have the possibility to either exonerate the innocent or to add additional evidence against the guilty,” he said. “And that’s a significant burden, much more so than digging up a 5,000-year-old Indian site. But the ideas are still the same: you’re still reading the soil, piecing together the past, taking those clues and interpreting them, and trying to determine their meaning.”

About the Author

This e-mail address is being protected from spam bots, you need JavaScript enabled to view it is a freelance writer who covers topics related to law enforcement and the technology of crime scene and crash scene reconstruction. His office is located in Oregon City, Oregon.

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