Forensic Anthropology Casework Research Articles

Bone color changes and interpretation of the temperature/duration of fire exposure to human remains in the forensic context

AbstractIn both the archeological and forensic literature, experimental data have been used to equate the color of burned bone with the temperature to which it was exposed. While this may be applicable in the tightly controlled oxidizing environment of a furnace or crematorium, it is not representative of the more realistic dynamic conditions of fire events involving structures, vehicles, outdoors, and so forth, that are encountered in forensic anthropology casework. In this piece, we review the literature at the cross section of bone color and temperature and compare it to our own observations from experimental burns. We generate a cautionary path forward for future research as well as interpretation in applied contexts. Implying temperature based on burned bone color ignores other significant variables that are related to the degradation of the bone's organic matrix like, the amounts and types of fuels, duration, fluctuations of temperature, oxygen level of the environment, byproducts of combustion, and other variables unique to each scene. Research results on bone color and temperature derived from controlled environments using non‐fleshed bone samples, are not applicable for use in forensic casework involving burned human remains from fleshed bodies. We argue that to do so distracts from other contributing variables and information that can be derived from the analysis of fire patterns on burned human remains and burned bones. Finally, we caution about using bone color alone to estimate temperatures of the fire, which makes incorrect assumptions about fire behavior and could jeopardize court testimony if this method is used as a standard. We raise three issues if a direct correlation between temperature and bone color are used in court: (1) other important factors are ignored, (2) a universal unvaried exposure of the body is assumed, and (3) the expert risks impeachment given conflicting data on the correlation.This article is categorized under: Forensic Medicine > Death Scene Investigation Forensic Anthropology > Taphonomic Changes and the Environment

Investigating identification disparities in forensic anthropology casework.

Forensic anthropology is shifting to reflect on the impact of its practices within the criminal justice context in important ways. Here, we contribute to this essential work by examining how decedent demographics as well as estimations of biological profile components are related to identification trends in forensic anthropology cases. The study uses data from more than 1,200 identified and unidentified forensic anthropology cases from three agencies (together representing a nation-wide sample). We found the following: i) multivariate analyses indicated that decedent sex, age, and race and/or ethnicity are not related to case identification rates in the pooled United States sample, ii) when identification rate differences do occur, they appear to be smaller effects, more agency-specific, and/or related to the context of a particular agency, iii) for the agency-specific sample with available data, there was no consistent evidence for a discrepancy in the duration of an identification investigation based on a decedent's sex, age, or race and/or ethnicity, iv) forensic anthropological estimations of sex, age, and ancestry can improve the odds of identification for decedents, although these are small effects, and v) reporting an ancestry estimation does not appear to impact decedent race representation among resolved unidentified person cases. Although previous studies have identified demographic discrepancies in other areas of the criminal justice system, the results presented here suggest that decedent demographic estimation practices by forensic anthropologists in general do not appear to be related to discrepancies in identification trends, but more research is needed to examine whether these findings hold. Contextual factors and practices specific to each investigative agency likely contribute to identification trends.

The effects of diet and beauty products on the uptake and storage of 14C in hair and nails: ramifications for the application of bomb pulse dating to forensic anthropological casework

Radiocarbon dating is a useful tool in the examination of unknown human remains. Recent studies have shown that the analysis of hair and nail samples can provide a highly accurate estimation of the year of death (YOD). However, little research has examined factors that may influence the uptake and storage of 14C in these tissues, such as diet, or the use of beauty products. This study measured the level of 14C in human hair and nail samples collected from living individuals to determine whether diet, and the use of hair dye or nail polish, has a significant impact on the estimation of YOD. The results of this study showed that diet did not appear to impact the radiocarbon content in human hair and nail, and thus should not be considered a limitation when analysing samples obtained from unidentified human remains. The use of nail polish, and in the majority of cases, hair dye, did not significantly impact the 14C concentration in nails and hair. While the results of this study are preliminary, they suggest that in most cases, both hair and nail can be successfully analysed using radiocarbon dating to estimate an individual’s YOD. However, best practice should involve the analysis of multiple tissue types, to minimise any error that may be introduced as a result of the decedent’s use of beauty products.

If you see something, say something: Structural vulnerability data and reporting in forensic anthropology casework

If you see something, say something: Structural vulnerability data and reporting in forensic anthropology casework

Engaging Undergraduate Students in Forensic Anthropology Research During Times of Restricted Lab Access: The Efficacy and Importance of Student-Led Surveys

The impacts of the COVID-19 pandemic on experiential learning have been felt by students interested in forensic anthropology casework and lab training. Without access to labs and with cancellations of courses related to hands-on learning like human osteology and forensic anthropology, students may not receive critical training necessary in their fields of interest. In this paper, we explore one potential option for engaged forensic anthropology research: the creation of skeletal research surveys that students can design and disseminate to law enforcement to better understand the nature of forensic casework in their own states. Students reported a high satisfaction rate with these survey projects and were able to build networks that helped them refine their post-graduation education and career goals. By formulating questions, creating surveys, submitting to the review board, and synthesizing data, students were able to explore forensic topics without entering a traditional lab setting during times of university lockdowns. The data from this research can be used by forensic anthropology students and professors in the future to better assist law enforcement with the identification of skeletal remains. The surveys described in this paper are easily replicated by other professors seeking to provide students with low-cost, remote forensic research opportunities.

Survival of sharp force trauma in burnt bones: effects of environmental factors

This study investigates how environmental variables, such as temperature and rainfall, affect previously induced cut marks on burnt bones. This research used non-serrated and serrated blade knives to inflict trauma on Sus scrofa ribs (n = 240). The bones were later burnt and left for 1 month in a taphonomic experimental facility. Qualitative and quantitative examinations were conducted using macroscopic and microscopic techniques to assess specific characteristics of the cut marks. Any changes to the dimension and morphology of the cut marks as well as their level of fragmentation were recorded.This study has led to three important outcomes: (1) identification of pre-existing cut marks is possible in reconstructed burnt bone fragments; (2) cut marks from different types of knife blades showed dissimilar responses to heat and the environment; and (3) specific environmental variables affect burnt bone fragmentation. These results have implications for trauma analysis on burnt remains in forensic anthropology casework.

Analysis of fusion of sphenooccipital synchondrosis using computed tomography in Turkish population

ABSTRACT Ossification centres in the adult skeleton are important markers for age estimation. Sphenooccipital synchondrosis (SOS) is of particular significance in forensic anthropology case work due to its late closure in adolescent age groups. The aim of this study is to evaluate the SOS fusion degree for age estimation of the Turkish population. In this study, images of 298 patients within the age of 5 to 25 years were retrospectively examined. The fusion degree of the SOS was assessed using a 5-stage system. Eight morphological measurements were taken from sagittal images and completely open types. We found that the upper end width of the synchondrosis was significantly lower than the lower end width of the synchondrosis. SOS fusion began at the superior border of the synchondrosis. Fusion starts 2 years earlier in females than in males, and the process of fusion completes at the age of 17 years in males and at the age of 19 years in females in this study. In conclusion, we consider that the differences in SOS fusion among studies are due to racial diversity and different methodologies and the SOS fusion stage is as a supportive evidence for age estimation in the presence of other clues.

Forensic anthropology casework at the Cook County Illinois Medical Examiner's Office, Chicago, IL, 2012-2022.

Forensic anthropology has grown in recent years with increased methodological standardization, technical advancements, and increasing numbers of academic institutions offering coursework and programs at the undergraduate and graduate levels. However, few practicing forensic anthropologists publish the composition of their casework, resulting in limited understanding of the true mechanics of the field by academics and forensic professionals. This study reports on forensic anthropology casework at the Cook County Medical Examiner's Office between March 2012 and February 2022. A total of 132 cases were evaluated. Results indicate that peak months of discovery were June (n=19) and September (n=17), with the fewest in January (n=5). Most discovery contexts were outdoor surface recoveries (n=55) and were fully skeletonized (n=47). The majority of consultation requests consisted of biological profile estimation (n=99). An average of 77.1 days elapsed from discovery to anthropology consult, 60.3 days from consultation to anthropological analysis, and 14.1 days from analysis to report submission. Assessment of the data indicates that the impact of seasonal variation, changing Medical Examiner personnel, as well as the complexity of cases influence forensic anthropology casework in Cook County. Report and discussion of forensic anthropologists' casework strengthens our understanding of the field, allows for the formulation of best practices, and serves as data upon which decisions regarding protocol, funding, resources, and need can be based. With additional practitioners collecting and sharing their data, a clearer understanding of the scope and utility of the field will be appreciated by colleagues and the greater forensic scientific community.

Anthropometry of the sternum: An autopsy-based study for sex determination.

Sex determination is one of the key components for establishing the individual's identity in forensic anthropology casework. It is a known fact that anthropometric assessment can have population-specific variations. The present autopsy study was conducted on the sterna of 102 cadavers (52 males and 50 females) of age more than 25 years at a tertiary care centre in Central India. Anthropometric measurements included the length of the manubrium (M), mesosternum (B) and combined length of manubrium and mesosternum (CL). Applicability of Hyrtl's law, Ashley's rule and the sternal index were also assessed for sex determination. A statistically significant correlation (p < 0.001) was observed between sternal measurements and the sex of the study population. The highest coefficient of correlation was seen between sex and the combined length (r = 0.726), followed by mesosternal length (r = 0.620), and manubrial length (r = 0.509). The difference between the means of the sternal index in males and females was not statistically significant (p > 0.05), and the difference between the means of the ratio of the body with manubrium in males and females for Hyrtl's law is also not found to be statistically significant (p > 0.05). It is concluded that the length of the body and the combined length of manubrium and mesosternum are valuable criteria for sexing the sternum in an adult population of Central India. The sternum can be useful for sex determination, particularly when bones like skull, pelvis, or long bones are not available or fragmented.

Steam Kettle Skeletal Preparation

This paper presents methods for the disarticulation and steam kettle maceration of embalmed and non-embalmed decedents for forensic casework and curation in anatomical collections. As steam kettles are becoming more commonly used, details on infrastructure and necessary tools for steam kettle maceration are included. This technique was developed over the course of four years of steam kettle use for forensic anthropological casework and full body anatomical donation macerations for Western Michigan University Homer Stryker M.D. School of Medicine’s (WMed) Body Donation Program. Steam kettle maceration efficiently processes decedents and results in high quality skeletal specimens with little to no damage. Furthermore, this method has the advantage of requiring minimal disarticulation, no chemical agents, and minimal intervention or attention by the processor.

Forensic Tools for Species Identification of Skeletal Remains: Metrics, Statistics, and OsteoID.

Simple SummaryForensic anthropologists are commonly asked to determine whether bones are of human origin and, if not, to which species they belong. Current practice usually relies on visual assessments rather than quantitative analyses. This study aimed to test the utility of basic bone metrics in discriminating human from nonhuman elements and assigning faunal species. A database of more than 50,000 skeletal measurements was compiled from humans and 27 nonhuman species. Equations and classification trees were developed that can differentiate human from nonhuman species with upwards of 90% accuracy, even when the bone type is not first identified. Classification trees return accuracy rates greater than 98% for the human sample. These quantitative models provide statistical support to visual assessments and can be used for preliminary assessment of a bone’s forensic significance at a scene. The statistical models, however, could not classify species at acceptable rates. For species identification, a freely available web tool (OsteoID) was created from the study data, where users can filter photographs of potential bones/species using a few basic measurements and access 3D scans and additional resources to facilitate identification. OsteoID provides an important resource for forensic anthropologists lacking access to large comparative skeletal collections, as well as other disciplines where comparative osteological training is necessary.Although nonhuman remains constitute a significant portion of forensic anthropological casework, the potential use of bone metrics to assess the human origin and to classify species of skeletal remains has not been thoroughly investigated. This study aimed to assess the utility of quantitative methods in distinguishing human from nonhuman remains and present additional resources for species identification. Over 50,000 measurements were compiled from humans and 27 nonhuman (mostly North American) species. Decision trees developed from the long bone data can differentiate human from nonhuman remains with over 90% accuracy (>98% accuracy for the human sample), even if all long bones are pooled. Stepwise discriminant function results were slightly lower (>87.4% overall accuracy). The quantitative models can be used to support visual identifications or preliminarily assess forensic significance at scenes. For species classification, bone-specific discriminant functions returned accuracies between 77.7% and 89.1%, but classification results varied highly across species. From the study data, we developed a web tool, OsteoID, for users who can input measurements and be shown photographs of potential bones/species to aid in visual identification. OsteoID also includes supplementary images (e.g., 3D scans), creating an additional resource for forensic anthropologists and others involved in skeletal species identification and comparative osteology.

Forensic anthropology casework from Switzerland (Bern): Taphonomic implications for the future

Retrospective, observational studies of forensic casework enhance knowledge on topics such as postmortem interval (PMI) estimations and search strategies. This 10-year survey of forensic anthropology (FA) casework performed at the Department of Physical Anthropology in the Institute of Forensic Medicine in Bern, Switzerland, provides insights into a variety of human bone cases recovered in different circumstances. In this study, we present 58 cases from our forensic database. The surveyed forensic cases comprise a high proportion of dispersed remains, leading to low recovery rates. In addition, about a third of the cases were discovered in the Swiss Alps. Future studies and research should concentrate on enhancing the recovery rate in outdoor forensic scenes and on research in PMI estimation. This is especially important for remains found in high altitudes, because due to the melting glaciers, we expect more previously covered and frozen remains to be released in the following years. Systematic, longitudinal case reviews further provide a reference that can be used to refer to in FA expertises.

Forensic anthropology casework performance: Assessing accuracy and trends for biological profile estimates on a comprehensive sample of identified decedent cases.

The purpose of this study was to investigate the accuracy rates and trends in forensic anthropology casework concerning the estimation of the biological profile (sex, age, ancestry, and stature). Identified cases from the Forensic Anthropology Database for Assessing Methods Accuracy (FADAMA; n=359) were analyzed to explore the following: accuracy rates per biological profile component, case-level performance in assessing the biological profile, and factors related to inaccuracy rates. Accuracy rates for the four biological profile components ranged from 83% to 98%, with sex estimation performing the best and stature performing the poorest. While the overall sex estimation inaccuracies were the lowest of any biological profile component, we found that females are missexed approximately ten times more often than males. Inaccurate age estimates were more frequently the result of overestimation than underestimation, while the trends are reversed for stature estimation. Regarding ancestry estimation performance, African American/Black and White decedents had the lowest inaccuracy rates, while Hispanic and Asian/Pacific Islander decedents demonstrated greater inaccuracy rates. When examining accuracy rates for each case, 81% of cases had no inaccurate biological profile estimates, while 17% and 2% inaccurately estimated one and two biological profile components, respectively. The demographic trends of identified forensic anthropology cases reflect the national unidentified decedent demographics. Biological profile accuracy rates were generally comparable to previous studies. The findings highlight the current status of forensic anthropologists' casework performance, with a greater amount of case-level inaccuracy rates than previously thought, and demonstrate the potential methodological and sampling strategies that could improve accuracy rates.

Identifying Handsaw Tooth Shape Based on the Micro- and Macroscopic Analysis of the Kerf Floor Contour

Skeletal trauma analysis is a major facet of forensic anthropology casework and can entail interpretation of sharp force saw trauma. Hand-powered saws are commonly used in cases of dismemberment and analysis requires differentiating class characteristics. Features of the kerf walls and floor provide information utilized in identifying set, shape, size, power, and direction of sawing motion of the tool. The focus of this study is to examine validity and reliability of determining tooth shape class characteristic (rip versus crosscut) from features of the kerf floor. Two crosscut and three rip handsaws, ranging from 6 to 16 teeth per inch, were used to make 30 incomplete cuts per saw for a total of 150 cuts. Each kerf floor was analyzed macroscopically and microscopically using a digital microscope at 30 × magnification by three observers of different experience levels (expert, experienced, and novice). Profile shapes were classified as U-shaped/concave (rip) or W-shaped/convex (crosscut) by each observer for all 150 cuts. Reliability tests using Cohen’s kappa ranged from substantial in the two less experienced observers to almost perfect in pairwise comparisons with the expert. Microscopic classification accuracy was 94.0% (423/450) for all three observers and macroscopic examination increased accuracy to 99.8% (449/450). Saw wear and tooth size were not a significant determiner in correct identification of saw tooth type. Overall, tooth shape can be reliably and accurately determined from incomplete cuts.

Examining the Reliability of Morphological Traits for Sex Estimation

Morphological skull and pubic traits are routinely used in forensic anthropological casework for sex estimation, with the Walker (2008) and Klales et al. (2012) methods commonly employed. This research aims to present a comprehensive evaluation of reliability in skull and pubic trait scoring and the implications of observer scoring variation on sex estimation accuracy. Results from previous studies are summarized and compiled into tables for comparisons. Data from this study are composed of a large compilation of Walker (2008) and Kales et al. (2012) trait scores (skull n = 392, pubic n = 443) contributed by seven researchers of varying levels of expertise. Intra- and interobserver analyses were performed on the trait scores, and variations in correct sex classifications were assessed among observers, with particular emphasis on the effects of observer experience. Statistical results indicate that the traits utilized in Walker (2008) and Klales et al. (2012) can be reliably scored except for the mental eminence, which has shown considerable variation among studies and individuals. Resultant sex estimations improved with experience level, with the highest accuracy rates for both methods among experts. Although novice observers had good agreement in trait scores with more experienced observers, minor scoring differences negatively impacted classification accuracy, particularly in the Klales et al. (2012) method with more than a 15% drop in accuracy. The results highlight the importance of experience and exposure to human variation and training in these sex estimation methods and also suggests data from expert practitioners can be combined into larger databases.

The impact of scavenging: perspective from casework in forensic anthropology

Forensic anthropology casework frequently encounters evidence of animal scavenging associated with fragmentation and loss of skeletal material. Published research demonstrates that patterns of destruction in bone can suggest the size and type of animal involved. This study analyzes 107 cases reported on by the first author at the Smithsonian Institution to investigate patterns of scavenging in forensic anthropology casework. This investigation reveals that the extent of scavenger impact varies across the body, but primarily is concentrated in the central body area. Although extensive animal scavenging can limit analysis, some evidence of foul play can be preserved.

The acetabulum as an adult age marker and the new IDADE2 (the IDADE2 web page).

In 2006, an age estimation method was proposed utilizing Bayesian inference to interpret age-progressive changes in the acetabulum. This was accompanied by the IDADE2 software to facilitate calculations. However, the MS-DOS operating system on which the software was based became obsolete. The main goal of this article is to present the new IDADE2, which incorporates web-based facilities. The original IDADE2 has been re-written in R and presented as a web page. As in the original, this web page uses Bayesian inference to estimate age of unidentified individuals. The materials used to create the reference datasets of this web page include acetabular scores from documented skeletal samples from Spain (n = 24♀ and 52♂), Portugal (n = 317♀ and 294♂), and the US (n = 370♀ and 456♂). The IDADE2 website has eight sections. Six of these are informative to guide the user. The other two (Option 1 and Option 2) are dedicated to estimating age at death. Option 1 allows users to estimate the age of individual(s) in their test sample based on our reference data of acetabular scores. Option 2 allows users to estimate age from the acetabulum with their own reference and test collections or-if the users prefer-another age marker and method of choice. The IDADE2 website is applicable both to forensic anthropological casework on single individuals and to bioarchaeological analyses of large skeletal samples. This website is easy to use and freely accessible, responding to previous critiques and incorporating method advancements.

Title Discoveries from the Forensic Anthropology Data Base: Modern American Skeletal Change &amp; the Case of Amelia Earhart

In the mid‐1980s the University of Tennessee (UT) Anthropology Department began accumulating data from forensic cases that came into our laboratory and others around the country providing the first insight into skeletal changes occurring in the past 150 years. Also in the 1980s the UT Forensic Anthropology Center founded a willed body program to study human decomposition. The donated body program formed the basis for an unprecedented collection of modern American skeletons for skeletal biology research. Thus began the Forensic Anthropology Data base (FDB), which now contains osteometric data from over 4000 individuals, most of them of known age, sex, and ancestry, as well as height, weight, place of birth, place of death, and other premortem biological characteristics of interest (e.g. handedness, pathologies, occupation).The FDB data base has resulted in a number of major developments and discoveries, three of which will be summarized in this presentation: Documentation of remarkable change in cranial and postcranial morphology in the past 150 years. The cranium has become higher, longer and narrower during this time interval. The skeleton has also become more gracile, and limb bone proportions have changed. Development of a software package, Fordisc 3.1, that uses the FDB and sophisticated statistical algorithms to estimate sex, ancestry and height from bone measurements. The Fordisc software program has changed the face of forensic anthropology casework since its inception in 1993. Probable identification of Amelia Earhart by comparing estimates of her bone lengths based on photographs to lengths of bones found on Nikumaroro Island in 1940. Support or Funding InformationNational Institute of Justice 85‐IJ‐CX‐0021This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Procedural and political aspects of forensic exhumation in Brazil

Exhumation may be defined as the legally sanctioned excavation and recovery of the remains of lawfully buried or – occasionally – cremated individuals, as distinct from forensic excavations of clandestinely buried remains conducted as part of a criminal investigation and from unlawful disinterment of human remains, commonly referred to as bodysnatching. The aim of this article is to review the role of exhumation – so defined – in the activities of CEMEL, the Medico-Legal Centre of the Ribeirão Preto Medical School-University of São Paulo, in international, regional and local collaborations. Exhumations form part of routine forensic anthropology casework; scientific research in physical and forensic anthropology; and forensic casework conducted in collaboration with the Brazilian Federal Police; and are carried out as part of humanitarian investigations into deaths associated with the civil–military dictatorship of 1964 to 1985. This article aims to offer a non-technical summary – with reference to international comparative information – of the role of exhumation in investigative and scientific work and to discuss developments in their historical and political context.

Population inference from contemporary American craniometrics.

This analysis delivers a composite picture of population structure, admixture, ancestry variation, and personal identity in the United States, as observed through the lens of forensic anthropological casework and modern skeletal collections. It tests the applicability of the probabilistic clustering methods commonly used in human population genetics for the analysis of continuous, cranial measurement data, to improve population inference for admixed individuals without prior knowledge of sample origins. The unsupervised model-based clustering methods of finite mixture analysis are used here to reveal latent population structure and generate admixture proportions for craniofacial measurements from the Forensic Anthropology Data Bank (FDB). Craniometric estimates of ancestry are also generated under a three contributor model, sourcing parental reference populations from the Howells Craniometric Dataset. Tests of association are made among the coefficients of cluster memberships and the demographic information documented for each individual in the FDB. Clustering results are contextualized within the framework of conventional approaches to population structure analysis and individual ancestry estimation to discuss method compatibility. The findings reported here for contemporary American craniometrics are in agreement with the expected patterns of intergroup relationships, geographic origins and results from published genetic analyses. Population inference methods that allow for the model-bound estimation of admixture and ancestry proportions from craniometric data not only enable parallel-skeletal and genetic-analyses but they are also shown to be more informative than those methods that perform hard classifications using externally-imposed categories or seek to explain gross variation by low-dimensional projections. Am J Phys Anthropol 160:604-624, 2016. © 2016 Wiley Periodicals, Inc.