Spatial analysis of mass grave mapping data to assist in the reassociation of disarticulated and commingled human remains

Abstract

When considering possible solutions to the problem of sorting commingled human remains from a mass grave context, one is inclined to think of methods conducted within a laboratory setting (Dirkmaat et al. 2005), such as physical pair-matching of skeletal elements, evaluating articulation of elements, statistical analysis of measurements taken from the elements, or other such techniques that use data generated during mortuary analysis (Buikstra et al. 1984; Byrd and Adams 2003); in short, techniques that focus on the remains well after they have been recovered from the grave. Data generated during the excavation of a mass grave unfortunately are not often consulted when attempting to tackle problems of commingling. Nevertheless, observations and recordings taken during proper excavation can directly assist in the reassociation of disarticulated and commingled remains. In particular, mapping data and grave depositional event recording can be valuable information for use in the reassociation of disarticulated body parts to their corresponding bodies. The potential of disarticulation and commingling of bodies and body parts is an issue in every mass grave. Not only are bodies initially commingled as they are deposited in the grave, but the condition of the bodies prior to burial, decomposition processes, taphonomic conditions within the grave, and the intentional destruction and/or tampering with the bodies by those who buried them contribute to the eventual disarticulation and mixing of elements, more so when an initial (primary) mass grave is disturbed and bodies aremoved to a secondary mass grave(s). Care in exposing and removal of remains from a grave by an observant excavator, knowledgeable in human skeletal anatomy, is the single most important step limiting (and hopefully eliminating) further disarticulation during the recovery. Without a controlled excavation, disarticulation will be compounded, further adding to the already confused mix within the grave. Yet careful exposure and removal of remains does not have to be the only contribution a proper excavation makes. A well-documented, archaeologically led excavation generates data that may be used not only for prevention of further commingling, but also for resolving commingled remains. Recognition of archaeological techniques and observations as potential key elements in assisting forensic case work has been acknowledged in the past (Dirkmaat and Adovasio 1997; Morse et al. 1976; Owsley 2001; Skinner 1987). Nevertheless, no suggestion has been proposed as to how archaeological observations can be logically and consistently utilized within mortuaries, especially those processing hundreds of remains from mass graves. Unfortunately, mass grave investigation is often sharply divided between two activities, recovery operations (grave excavation) and mortuary examination (autopsy), with neither activity having much contact with the other.While the forensic anthropologist or pathologist in charge of the mortuary may fully respect the contributions archaeology makes during the recovery operations, he may be unaware of the potential role archaeology can play in sorting commingled remains after the excavation. Archaeology, for the most part, is still very much viewed by mission planners as an outdoor (or at least out-of-mortuary) activity with no further connection to the mortuary other than delivering remains and associated evidence as intact as possible. Only under unusual circumstances does archaeology seem to be consulted during mortuary examination. For example, Haglund (2001) describes a circumstance where excavation maps displaying the position of remains within a mass grave were used to help sort out fragmented crania superimposed upon each other.While Haglund uses this example as one of several positive contributions archaeology can bring to the investigation of mass graves, he unfortunately does not detail how the maps were used. It is assumed that the physical maps, not the recorded spatial data used to create the maps, were consulted to help rectify the commingling issue. Furthermore, it seems that this use of excavation maps may have been an isolated example; that the maps were consulted only after the commingling issue with this particular case was recognized in the mortuary, and the use of maps was not a standard aspect of their mortuary operation. No further reference to map use within their mortuary was mentioned. In our study, a computer program is used to analyze spatial relationships between disarticulated and commingled remains within a mass grave. Similar to Haglund?s example using maps to assist in sorting commingled crania to adjacent bodies, the computer program examines the spatial data generated during the electronic survey of body and body parts within a grave and comparing the locations of disarticulated elements to all possible matching points. The hypothesis is that a disarticulated body part closest to the point on the body missing that part is the most likely correct match out of all other possible matching body parts within the grave. Such a program can be run prior to or during mortuary examination, providing mortuary personnel with immediate suggestions as to which disarticulated body part(s) may belong to a particular body. When confronted with hundreds of bodies and body parts from a mass grave to sort through, prior knowledge of potential matching elements can be an effective starting point for rectifying commingling issues. Although not a definitive method or technique for reassociation, spatial analysis provides an objective and systematic approach based on the nature of the grave that may aid in reassociations. In addition to generating data that can be analyzed spatially, an archaeological approach to mass grave excavation can identify events in the creation of the grave, which, in turn, has the potential to assist in resolving commingling issues. Specifically, the identification of depositional events of human remains within a grave, when combined with spatial analysis, can narrow the search parameters of possible matching disarticulated body parts within a group of recovered remains.