Patterned Thermal Destruction in a Forensic Setting

Steven A. Symes, Ph.D., D.A.B.F.A.1, Christopher W. Rainwater, M.S.2,3, Erin N. Chapman, M.S., M.A.4, Desina R. Gipson, B.A.4 and Andrea L. Piper, B.A.1,    1Department of Applied Forensic Sciences, Mercyhurst College, Erie, PA, USA,    2Office of Chief Medical Examiner, New York, NY, USA,    3Department of Anthropology, Centre for the Study of Human Origins, New York University and New York Consortium in Evolutionary Primatology, New York, NY, USA,    4Department of Anthropology, State University of New York at Buffalo, Buffalo, NY, USA

This chapter discusses the patterned thermal destruction of human remains in a forensic setting. In the rapidly changing world of forensic science, more specifically forensic anthropology, there is a necessity to understand and be able to interpret fire modification of human remains. With the enormous potential for fire and heat alterations to inhibit scientists’ abilities to interpret patterns to human remains, burn trauma analysis is inconsistent and has been slow to mature in many disciplines. The destructive forces of fire often significantly alter, damage or even destroy many recognisable patterns, characteristics and evidence that we normally depend on. This likely contributes to the existence and persistence of old and untested theories concerning burned bone where inaccurate interpretations, such as exploding skulls, persist for decades and terminology is inconsistent. In fatal fire cases, forensic anthropologists are primarily responsible for separating perimortem trauma from heat-induced fractures and for assigning temporal and sequential designations to trauma when possible. These findings may contribute to the determination of cause and manner of death, time of death and perpetrator behaviour.

Keywords

Fire; bone; heat induced fractures; patterned thermal destruction

Introduction to Burned Bone Research

Out of necessity, anthropologists have concerned themselves with fire modification studies because of the significant impact that fire and heat alteration of physical evidence and human remains have on their analyses and interpretations. Fire is a destructive force that can damage, alter or destroy valuable evidence essential to biological and contextual reconstructions. The ramifications of heat modification to bodies for anthropological and forensic analysis are numerous and diverse. Research studies focus on whether perimortem and antemortem trauma can be detected after cremation, whether it is possible to determine the body’s position and state of decomposition at the time of cremation, how and to what extent fire consumes bone in a fatal fire setting and whether biological parameters are obtainable after bone has been thermally altered (Stewart, 1979).

Interestingly, the same modifications that obstruct standard analyses may have evidentiary value as evidence of a concealed crime. The destructive forces altering remains and physical evidence also create recognisable patterns that, when viewed as evidence, can lead investigators to more accurate and comprehensive interpretations of fatal fire scenes. The correct interpretation of these artifacts is essential to modern forensic investigations, conferring new impetus to forensic anthropological research in the area of burned bone. Yet, a review of the anthropological literature reveals that the current methodologies for the analysis of burned human bone remains are often times, at best, contradictory and confusing.

The authors suggest that the main goal of forensic anthropology in the area of burned bodies is to ascertain enhanced methodologies for the collection, preservation and interpretation of bones altered by thermal processes to establish identity and recognise potential evidence of criminal activity, with an eventual goal of contributing to the cause and manner of death. Obviously, the effective collection and preservation underlies the success of all burn studies (Dirkmaat and Adovasio, 1997; Dirkmaat, 2002; Dirkmaat et al., 2008; Mayne Correia, 1997; Mayne Correia and Beattie, 2002; Krogman and İşcan, 1986). Without the proper collection, the data do not exist. Second, it is the opinion of the authors that experts like DeHaan (see Chapter 1 and numerous additional publications) have already synthesised fire investigation down to the basics, or essentially to the study of temperature, atmosphere and duration. Although this appears to be the most basic approach, many research topics appear to ignore one or two of these variables, with temperature often being the focus.

This study attempts to hold each of these variables constant while assuming that all burn victims requiring anthropological analysis have been exposed to high temperatures, engulfed in heat and flames and, although the duration is an essential ingredient in the mix, that the duration is simply enough time to severely alter the body, damage bone and sometimes create notable limb separation.

With this extent of burning destruction, we no longer have to measure degrees of temperature. Body positioning, beyond face up or down, is not of dire importance, and because the total body is consumed in fire long enough to exposed bony tissues, burning duration is also of reduced concern. With this standardisation of burned remains, the researcher is released from temperature, atmosphere and duration. Finally, the anthropologist is free to examine the body for patterns: areas of initial burn and secondary burning, amputations and areas last to burn. To give this charting real-time dynamics, it is possible to categorise body burn patterns using three diagnostic process signatures:

Charting thermal destruction may indicate a normal burn pattern or may flag a suspicious abnormal pattern.

Early Studies and Classification of Research

Much of the initial research on thermal modification of human skeletons was developed within an archaeological framework aimed at the interpretation of cultural cremation patterns. Early archaeological research in the area still provides today’s forensic anthropologists with a procedural baseline for the analysis of burnt bone today. Archaeologists studied burned human remains primarily to elucidate the conditions in which bone was exposed to fire (i.e., burning methods, temperatures achieved and whether the remains were dry, fresh or fleshed at the time of burning). They based their assessments on the examination of factors such as colour changes, fracture presence and fracture patterns in relation to the temperature and duration of heat exposure. As research advanced, quantitative traits, such as bone dimension changes caused by thermal processes, also began to be investigated (Binford, 1963; Stewart, 1979; Van Vark, 1970).

Ironically, one of the first anthropological studies on cremated bone, largely responsible for generating the classic archaeological studies on the subject, arose from the forensic field. In 1943, Wilton M. Krogman published Part 1 and Part II articles in the FBI Law Enforcement Bulletin, discussing variations in heat-induced alteration to wet and dry bone. In the publications, Krogman examined the differences confirmed by bones in physical characteristics such as bone colouration, fracture morphology and surface alteration, depending on the thickness of the overlying soft tissues.

After Krogman’s publication, other researchers soon realised the potential for translating Krogman’s observations into cultural inference. William S. Webb and Charles E. Snow (1945) used Krogman’s approach to study the cremation practices of prehistoric peoples in the Ohio River area. Webb and Snow aspired to differentiate Adena cremation practices from those of the earlier Hopewell cremations. They sought the opinion of Krogman (Stewart, 1979, p. 60), who concluded that, although some overlap was present, the Hopewell cremations were preferentially performed on defleshed, dry bones, whereas the Adena people practiced cremation mainly on fleshed bodies (Webb and Snow, 1945, p. 189).

Webb and Snow’s results were tested by Raymond Baby (1954), who examined cremated remains from Hopewell sites in Ohio. Based on the heat alteration patterns shown by the skeletal materials, Baby also sought to determine whether dismemberment was part of the Hopewell ritual. In addition to the observational study, Baby pioneered experimental research in the area by conducting a study in which a crematory furnace was used to compare heat alteration patterns in two unembalmed cadavers (fleshed and defleshed) and a sample of dry bone. Based on his experimental results and the patterns present in the archaeological samples, Baby concluded that the Hopewell cremations mainly involved fleshed bone, contradicting Krogman’s earlier determination put forth by Webb and Snow.

Baby’s (1954) and Webb and Snow’s (1945) conflicting interpretations serve to illustrate the necessity of examining multiple variables in the analysis of thermally altered bone as well as the importance and need for experimental work in the area. This debate was the first of many debates to arise regarding the interpretation of burned bones. Other early cremation...