Forensic archaeology

DEFINITION: Profession in which standard archaeological field methods are applied to the recovery of evidence from forensic scenes and archaeological theory and experimental research findings are applied in the interpretation of such scenes.

SIGNIFICANCE: Forensic scenes containing human remains and artifacts (representing homicides, suicides, or accidental deaths) are often initially investigated by law-enforcement personnel with limited experience in detailed data recording. When this occurs, much critical on-site evidence may be lost. The application of archaeological techniques of mapping and recovery allows for complete documentation of forensic scenes, which, in turn, permits more thorough interpretation of the events that created the scenes and strengthens the courtroom testimony of the law-enforcement officers involved.

Forensic archaeology is a specialized area in the broader field of forensic anthropology, focusing on field investigation as an initial stage in the analysis of crime scenes or other forensic settings. The goal of the application of archaeological methods is to obtain the maximum amount of information at a forensic scene before human remains and artifacts are removed to the laboratory for chemical or other analyses. Precise archaeological field techniques began to be developed in the late nineteenth century in England, but such techniques have regularly been applied to forensic investigations only since the 1990s. Areas of archaeology most directly applicable to include search-and-recovery methodology and interpretation.

Search and Recovery

Archaeological survey and excavation methods can readily be applied to forensic settings. The walkover survey, wherein individuals spaced at regular intervals along a line walk across an area and flag any remains or items visible on the surface, is one such method. If significant items are located during such a survey, then surveying equipment, such as a transit or compass, is used to establish a grid over the area for precise mapping of flagged items. Photographic documentation and production of detailed maps showing the locations of items before removal are vital in recording their spatial associations. The location of a datum, or a principal measuring point for a map, is triangulated to permanent landscape features or recorded by a global positioning system (GPS) device. In addition to human personnel, cadaver dogs may be used to detect decayed remains.

Such a survey can also identify disturbed soil or vegetation indicating a possible covert burial. Geophysical remote-sensing equipment, such as ground-penetrating radar, metal detectors, or proton magnetometers, can be used to detect remains buried at various depths. More intrusive methods, such as probing the ground with a metal rod or taking samples with a soil core or auger, may also be used.

For hidden or covert burials, excavation follows the standard archaeological procedures for excavating features, as is done for storage pits or cellars on archaeological sites. The identified burial area is first photographed, and then overlying leaf litter or other loose vegetation is cleared and a small grid (with a datum for a measuring reference point) is established over the identified area. A plan (horizontal) drawing of the area is made, and then one-half of the burial feature is initially excavated. Care is taken to leave objects or remains in place or, if they have to be removed, to photograph and record their horizontal and vertical (depth) measurements in relation to the grid. After complete excavation of the first half, a section (vertical) drawing is made of the wall of the remaining half of the feature, and the remaining portion is then excavated. All excavated soils are screened or sifted through small-mesh (usually one-quarter inch) hardware cloth to recover small items.

Through this process, the entire body, along with associated artifacts, is exposed. All remains and artifacts are photographed, inventoried, and placed separately in bags. Samples for specialized laboratory analysis are also collected during the course of excavation. Soil, plant material, and insect remains are sampled, as analysis of these can aid in the determination of the environment of the burial, whether the remains have been moved from another location, and time since death. Photography and mapping occur at every stage of the excavation. The end products are not only the recovered evidence but also descriptive notes, spatial measurements, and photographs of all items and their places in the forensic setting.

Internationally, methods are used in the investigation of mass graves resulting from genocide or other so that the persons responsible can be successfully prosecuted based on recovered evidence. Forensic archaeology methods have been used to collect evidence in such human rights cases in Argentina, Guatemala, Peru, Central Europe, and Iraq, as well as other regions. In the twenty-first century, forensic archaeology has also been utilized in identifying the victims of natural disasters.

Interpretation

Experimentation to reconstruct past events and artifacts has a long history in archaeology. Such experimentation is based on the hypothetico-deductive method, wherein researchers first examine observations from a variety of specific cases to develop broad hypotheses explaining the observations. Then, using new data from new experiments, the researchers test these hypotheses for their validity. In archaeology, these tests are referred to as actualistic studies; in these studies, researchers make experimental observations in the present and then use those observations to interpret past events or processes.

Experimental archaeological studies of taphonomy, or the decay process that transforms living organisms after death, and theoretical explanations of this process can be used to interpret forensic scenes. For example, archaeologists might give a fresh nonhuman bone to a carnivore, such as a dog, and observe the animal’s chewing behavior. Which parts of the bone are chewed first? How does a carnivore degrade the bone over specified time periods? What are the special markings left on the bone signifying carnivore activity? How far have bones been moved from their original locations? Answering these questions through direct observation can help forensic scientists interpret crime scenes by comparing recovered bones to known experimental examples.

Many studies of this kind have been done to document the effects of carnivores, rodents, and even vultures on remains from forensic scenes. Application of the findings from experimental studies of movement or alteration of remains by scavenging animals, weathering effects, and extent of decay can thus help forensic archaeologists to distinguish natural from human-induced damage and can aid in the determination of time since death. Investigators may also reconstruct the chain of events leading to a given forensic scene through careful attention to these taphonomic effects and the recorded field data. Law-enforcement efforts thus benefit not only from the precise recording methods provided by forensic archaeology but also from enhanced interpretive data based on scientific experimentation in the field.

Bibliography

Byers, Steven N. and Chelsey A. Juarez. Introduction to Forensic Anthropology. 6th ed., Routledge, 2023.

Dupras, Tosha L., et al. Forensic Recovery of Human Remains: Archaeological Approaches. 2d ed., CRC Press, 2012.

Haglund, William D., and Marcella H. Sorg, eds. Advances in Forensic Taphonomy: Method, Theory, and Archaeological Perspectives. Boca Raton, Fla.: CRC Press, 2002.

Hanson, Ian, James Fenn. “A Review of the Contributions of Forensic Archaeology and Anthropology to the Process of Disaster Victim Identification.” Journal of Forensic Sciences, 24 June 2024, doi: 10.1111/1556-4029.15553. Accessed 14 Aug. 2024.

Killam, Edward W. The Detection of Human Remains. 2d ed. Springfield, Ill.: Charles C Thomas, 2004.

Komar, Debra A., and Jane E. Buikstra. Forensic Anthropology: Contemporary Theory and Practice. New York: Oxford University Press, 2008.