To forensic anthropologists, the analysis of human bone opens the portal of scientific truth that enables the justice system to discover the facts and circumstances surrounding criminal acts. Trained in anthropology, archaeology, human osteology, and chain-of-evidence procedures, forensic anthropologists are primary players in forensic science both in the field and in the laboratory.
The resolution of civil or criminal trials can depend upon the systematic recovery and collection of physical evidence in the field, rigorous scientific analysis in the laboratory, and protection of the integrity of the evidence. Typically, federal, state, and county evidence response teams collect and analyze physical evidence, including the human skeletal remains. However, forensic anthropologists are often called upon by such agencies to help in this endeavor. As such, forensic anthropologists have used their skills in the analysis of victims of homicides, accidental deaths, natural deaths, and mass fatalities.
Our archaeological training, in particular, comes into play in the field as we methodically search and meticulously recover human remains and other physical evidence from a crime scene. This is especially crucial because the recovery process itself is destructive. Scene responders have one "contamination-free" chance to recover all of the physical evidence, photograph the human remains, bullet casings, or cigarette butts in place, map these items relative to each other and other scene features, and collect the necessary data.
In the laboratory, forensic anthropologists use their knowledge of human osteology and anatomy to help medical examiners or coroners identify the victim, reconstruct what happened at the time of death (e.g., was there foul play?) and what occurred after death (e.g., did animal scavengers chew on the victim?s hands and feet?). The victim?s bones are visually, stereoscopically, and radiographically examined so that we can determine the age, sex, stature, and ancestry of the victim.
But forensic anthropologists also realize that the biological profile derived from skeletal examination has the potential to reveal the victim?s personal history. For example, fine horizontal grooves on the victim?s front teeth (incisors) indicate that the victim may have been very ill or malnourished when these teeth were developing during childhood. Fractures to bones of the face, ribs, and hands that are in various stages of healing may suggest a history of violence in the domestic setting, while the presence of orthopedic implants in the knee may have resulted from sports-related injuries. As such, creation of the victim?s biological profile often uncovers clues regarding the victim?s life history, a revelation that will hopefully facilitate the victim?s positive identification.
Once the biological profile of the victim is completed, the next step is the forensic anthropologist?s analysis of trauma that occurred around the time of death. Skeletal trauma analysis is a time-intensive process. If done correctly, this analysis can reveal secrets surrounding the circumstances of death. Yet, identifying whether a mark was caused by a knife stabbed into the victim at the time of death or by lawn mower blades hitting the bones months or years after death can only come from the experience of years spent evaluating thousands of bones, whether in a morgue, laboratory, or museum. For this reason, coroners, medical examiners, and other forensic specialists rely upon the expertise of forensic anthropologists.
Forensic anthropologists are also trained to evaluate and recognize how environmental conditions alter the appearance and composition of bone over the span of time since death. For example, an untrained eye can mistake the chafing or erosion of the braincase by water or wind for a wound that occurred at the time of death. Similarly, conical depressions and tiny parallel grooves can be interpreted as knife wounds, but may actually be tooth marks from carnivores or rodents, respectively. Thus, skeletal trauma analysis differentiates between patterns of violent trauma caused by a weapon at the time of death and fracturing or breakage caused by animals or weathering after death.
Because forensic anthropologists are typically better equipped to locate and map the human skeletal remains and eliminate rocks, sticks, and animal bones from the evidence collection, our activities allow investigating agencies to reallocate their resources to other facets of the investigation. For example, many of the forensic anthropologists called to help in the recovery of victims of the 11 September World Trade Center attack (of which I was one) were tasked with sorting the human remains from the incomprehensible volume of nonhuman material, rocks, sticks, and other debris. Although we did not use our skills to positively identify the victims in this case, our work sped up the identification process conducted in large part by DNA and dental experts. For these reasons, forensic anthropologists have become scientific linchpins for many forensic investigations, helping in the recovery and analysis of the victims of mass fatalities in addition to tying the perpetrators of crime to the victim and weapon by using our knowledge of tool marks on bone.
The inclusion of forensic anthropologists early in an investigation helps to ensure maximum recovery and protection of the human skeletal remains and allows the evidence response team members to focus upon other lines of evidence (fingerprints, fibers, DNA). Furthermore, a forensic anthropologist?s skeletal analysis helps to identify the victim and determine how the victim may have died. Because of the nature of the cases that they work on--victims that are badly decomposed, skeletonized, or when body parts are missing--the forensic anthropologist is often the victim?s last chance for identification and justice.