DNA identification in mass fatality incidents

DNA identification has become an important aspect of mass fatality management as well as in other instances of difficult identification of human remains. Most large mass fatality incidents will require DNA identification. Medical examiners should prepare for such potential eventuality. Whether DNA is tested, in mass fatality incidents, DNA specimens should be obtained from remains as well as from next-of-kin for potential testing. DNA identification is neither as slow nor as expensive relative to the overall fatality management as is commonly assumed. This article sought to provide medical examiners with a framework for DNA identification in mass fatality incidents.     

Human Identification by Oral Prosthesis Analysis with Probability Rates Higher than DNA Analysis

Several techniques are used to perform an appropriate and reliable human identification. Forensic dentistry has achieved great relevance over the past years. The aim of this article is to report the method used for the identification of a male body found in the colliquative stage of putrefaction. The identification of the victim was succeeded confronting the dental findings found in the corpse with the data present on dental records provided by his dentist. The major elements for the identity′s recognition were a metal core and a prosthetic crown that were being fabricated. These elements associated with the dental records were compelling for the elucidation of the case, and a positive body identification was achieved with high levels of probability. In the present case, cadaveric analysis of stomatognathic system structures achieved a probability value higher than DNA identification techniques, emphasizing the importance of forensic dentistry.     

Some mathematical problems in the DNA identification of victims in the 2004 tsunami and similar mass fatalities

DNA is a major and essential identification tool for mass fatality incidents including the hundreds of thousands of victims of the 2004 Indian Ocean tsunami. Mathematical complications characteristic of this sort of mass fatality include prevalence of related victims, the many races represented among the victims, and various identification modalities in tandem with DNA. Four mathematical problems of interest are discussed in this paper. (1) Other quantifiable factors (i.e. geography) can be formally accounted for by including a likelihood ratio that can be thought of as reducing the "effective number of victims." (2) When a victim is found and tentatively identified as V, but then it comes to light that the victim has a relative W who is also missing, confidence in the identity is depressed. To account for the existence of W, increment the effective number of victims by the likelihood ratio supporting W as the identity of the victim. (3) When several apparently related victims are found, their mutual identities should be calculated simultaneously. Compared to one-at-a-time, serial identifications, this is both logical and may lead to much more confidence in the identities. (4) Although there may be many different population groups represented among the missing, it is generally sufficient to consider population statistics for only a few of them in deciding whether to declare an identification.     

DNA Profiling Success Rates from Degraded Skeletal Remains in Guatemala

No data are available regarding the success of DNA Short Tandem Repeat (STR) profiling from degraded skeletal remains in Guatemala. Therefore, DNA profiling success rates relating to 2595 skeletons from eleven cases at the Forensic Anthropology Foundation of Guatemala (FAFG) are presented. The typical postmortem interval was 30 years. DNA was extracted from bone powder and amplified using Identifiler and Minifler. DNA profiling success rates differed between cases, ranging from 50.8% to 7.0%, the overall success rate for samples was 36.3%. The best DNA profiling success rates were obtained from femur (36.2%) and tooth (33.7%) samples. DNA profiles were significantly better from lower body bones than upper body bones (p = <0.0001). Bone samples from males gave significantly better profiles than samples from females (p = <0.0001). These results are believed to be related to bone density. The findings are important for designing forensic DNA sampling strategies in future victim recovery investigations.     

Differential Identification of Three Young Housefire Victims: Methods when Age Assessment Fails

Multiple fatality incidents involving more than one child of statistically same age (including twins) can be challenging from an identification standpoint. This case details an urban fire, in which four children perished. Age assessment on three of the victims utilizing maturity staging described by Moorrees, Fanning, and Hunt yielded insignificant results. However, a plot of the MFH data shows the difference between two identical twins and a third child. The twins share a similar growth pattern, whereas the other was different. Based on this graphical interpretation, the nontwin victim was positively identified through exclusion. These results were verified through statistical testing. This case demonstrates a method to repurpose age assessment data to graphically distinguish between child victims. Further, it is shown that radiographic and clinical presentation in childhood identical twins can elicit genetic versus acquired similarities and differences, which can be used for identification of individuals and exclusion of others.     

The Odontology Victim Identification Skill Assessment System*,†

Abstract: Mass fatality identification efforts involving forensic odontology can involve hundreds of dental volunteers. A literature review was conducted and forensic odontologists and dental educators consulted to identify lessons learned from past mass fatality identification efforts. As a result, the authors propose a skill assessment system, the Odontology Victim Identification Skill Assessment System (OVID‐SAS), which details qualifications required to participate on the Antemortem, Postmortem, Ante/Postmortem Comparison, Field, and Shift Leader/Initial Response Teams. For each qualification, specific skills have been identified along with suggested educational pedagogy and skill assessment methods. Courses and assessments can be developed by dental schools, professional associations, or forensic organizations to teach and test for the skills required for dental volunteers to participate on each team. By implementing a system, such as OVID‐SAS, forensic odontologists responsible for organizing and managing a forensic odontology mass fatality identification effort will be able to optimally utilize individuals presenting with proven skills.     

Intra‐ and Inter‐Element Variability in Mitochondrial and Nuclear DNA from Fresh and Environmentally Exposed Skeletal Remains,

Successful identification of skeletonized remains often relies upon DNA analyses, frequently focusing on the mid‐diaphysis of weight‐bearing long bones. This study explored intra‐bone DNA variability using bovine and porcine femora, along with calcanei and tali. DNA from fresh and short‐term environmentally exposed bone was extracted utilizing demineralization and standard lysis buffer protocols, and DNA quantity and quality were measured. Overall, femoral epiphyses, metaphyses, and the tarsals had more nuclear and mitochondrial DNA than did the femoral diaphyses. DNA loss was much more rapid in buried bones than in surface exposed bones, while DNA quality differed based on environment, but not bone region/element. The demineralization protocol generated more DNA in some bone regions, while the standard lysis was more effective in others, and neither significantly affected DNA quality. Taken together, these findings reinforce the importance of considering inter‐ and intra‐bone heterogeneity when sampling skeletal material for forensic DNA‐based identifications.     

Different skeletal elements as a source of DNA for genetic identification of Second World War victims

To this day process of identification of missing persons from skeletonized human remains with help of forensic genetics proves to be complex and challenging. The success rate of genetic identification in bones strongly depends on a combination of various factors, most importantly environmental factors and post-mortem interval. Furthermore, there are individual-specific factors that affect DNA preservation, such as race, gender, age and type of skeletal elements. The goal of our study was to optimize sampling process through determining which skeletal elements are superior in their preservation of DNA in 70-yearold skeletons belonging to victims of Second World War. We sampled different types of bones and teeth from three such skeletons found in Slovenian hidden mass grave Huda jama, 56 elements from each respective skeleton, together 168 elements. With the help of parameters, such as quantity of DNA, degradation rate and typing success, we tried to find the best types of elements to identify the victims. Prior to powdering bones and teeth, we removed contaminants. We decalcified 0.5 g bone and tooth powder followed by extraction and purification of DNA using Biorobot EZ1 (Qiagen). Quantification of obtained nuclear DNA was carried out using PowerQuant kit (Promega) and autosomal STR typing using ESSplex SE QS kit (Qiagen). Best parameters to assess skeletal elements that are superior in their DNA preservation were quantity of DNA and number of successfully typed STR loci. Metacarpal and metatarsal bones proved to be the best, followed by intermediate cuneiform, first distal foot phalanx, talus, petrous bone and tibia. We also created elimination database for persons involved in exhumation, anthropological and genetic analyses and exclude potential contamination.     

Estimation of Living Stature from Selected Anthropometric (Soft Tissue) Measurements: Applications for Forensic Anthropology

Abstract:  Estimation of living stature has obvious utility in the identification process. Typically, anthropologists estimate stature from the measurement of long bone length. This type of analysis is traditionally conducted on skeletonized or badly decomposed remains, so collection of the necessary bone measurements is relatively simple. As the role of anthropologists expands into medical examiner offices and mass fatality incidents, the analysis of fleshed bodies and body parts is a more common scenario. For stature estimation in these types of cases (e.g., analysis of body portions recovered from an aircraft crash site or from intentional dismemberment), the presence of soft tissue on the human remains would usually necessitate dissection to expose skeletal elements to derive metric data for stature estimation. In order to circumvent this step, this paper provides various formulae that allow for standard anthropometric (i.e., soft tissue) measurements to be used in place of skeletal measurements. Data were compiled from several anthropometric studies (National Health and Nutrition Examination Survey [NHANES] and U.S. Army Anthropometric Survey [ANSUR]) and numerous regression models are presented. Results are compared between skeletal measurements and the anthropometric measurements from each study. It was found that the ANSUR models are similar to the skeletal models, while the NHANES models exhibit weaker correlation coefficients and higher standard errors. Overall, this study finds that stature estimates derived from anthropometric data provide good results and remove the necessity for dissection when working with fleshed body portions.     

Positive identification by a skull with multiple epigenetic traits and abnormal structure of the neurocranium, viscerocranium, and the skeleton

Wormian bones are small ossicles appearing within the cranial sutures in more than 40% of skulls, most commonly at the lambdoid suture and pterion. During the skeletal analysis of an unidentified male war victim, we observed multiple wormian bones and a patent metopic suture. Additionally, the right elbow was deformed, probably as a consequence of an old trauma. The skull was analyzed by cranial measurements and computerized tomography, revealing the presence of cranial deformities including hyperbrachicrania, localized reduction in hemispheral widths, increased cranial capacity, and sclerosis of the viscerocranium. Besides unique anatomical features and their anthropological value, such skeletal abnormalities also have a forensic value as the evidence to support the final identification of the victim.     

The Successful Recovery of Low Copy Number and Degraded DNA from Bones Exposed to Seawater Suitable for Generating a DNA STR Profile

A universal method allowing for DNA profiling from bones exposed to seawater has not been reported yet. This study refers on the identification of a body immersed in seawater for 8 months. The biological material for identification was the mandibular body, usually characterized by low success rates of DNA analysis. Initially, two extraction protocols were performed with negative results: one used for bones immersed in fresh water and a silica‐column procedure. A third protocol was performed, which combined the extraction of a higher amount of bone powder, the use of multi‐silica‐based extraction columns followed by a concentration step. This protocol allowed to obtain low copy number DNA and to generate a 12‐loci STR profile by combining conventional STR typing and mini‐STR technologies. This protocol could be suitable when human bones have been exposed to severe environmental conditions, and the available nuclear DNA is highly degraded and in low copy number.     

Antemortem and Postmortem Nonapposite Data—A Multidisciplinary Identification Strategy

Identification of human remains is often achieved by comparing documented reference data with the same type of evidence obtained from the remains. We present a case of a decomposed unidentified body, whose identity was presumed but because of the low validity range of the available data, the identification process could not be completed. Antemortem radiographs of the teeth found in the house of the reputed victim could not be compared to the edentulous cadaver and the kinship between the victim and the only living relative that could provide DNA for comparison was too tenuous. Isolated teeth found at the scene, were neither a source of DNA reference information nor questioned data to be compared to the antemortem radiographs. The strategy implemented by the investigators to reallocate the status of the isolated teeth from the questioned source to the reference source of DNA to be compared with the cadaver is presented.     

An Analysis of Hounsfield Unit Values and Volumetrics from Computerized Tomography of the Proximal Femur for Sex and Age Estimation

Sex and age are two elements in the establishment of a biological profile for forensic identification. While the pelvic bones are the most ideal structures for sex estimation, the condition of a body is not always ideal due to the nature of death, such as in mass disasters, or postmortem processes. This study utilized CT scans and resultant 3D models of 100 male and 100 female adults of known ages ranging from 18 to 98 years old to collect volumetric and Hounsfield unit measurements of the proximal femur. Equations were created to establish logistic regression models for sex estimation and linear regression models for age estimation. The resultant sex estimation method had an accuracy of 93.5% and utilized the volume of the proximal femur. This study provides three linear regression models for age with an accuracy range of 86%–92% ±12 years. As imaging technologies are increasingly adopted for forensic purposes, the power of 3D data will provide the opportunity for more quantitative and reproducible analyses. The proposed method for sex and age estimation provides a reliable tool that can be utilized in both day-to-day casework and disaster victim identification.     

Fingering a Murderer: A Successful Anthropological and Radiological Collaboration*

Abstract: We illustrate an interdisciplinary approach to identify a victim in a case with complex taphonomic and procedural issues. Burning, fragmentation, species commingling, and examination by multiple experts required anthropological preparation and analysis combined with radiographic adaptations to image and match trabecular patterns in unusually small, burned specimens. A missing person was last seen in the company of a reclusive female on a remote rural property. A warranted search found several burn sites containing human and animal bones. Fragment preparation, analysis, and development of a biological profile by anthropologists enabled examination by the odontologist, molecular biologist, and radiologist, and justified use of antemortem radiographs from one potential victim. Visual and radiological comparison resulted in a positive (later confirmed) identification of the victim by radiological matches of three carpal phalanges. Although some dimensional changes are expected with burning, morphological details were preserved, aided by selection of relatively intact, small bones for comparison.     

Implant Bone Integration Importance in Forensic Identification

Odontological identification consists of the comparison of antemortem dental information regarding a missing person with postmortem data from an unidentified corpse or human remains. Usually, the comparison concerns morphologic features that the operator chooses among all the visible characteristics because of inter‐individual uniqueness; for this reason, implants can be of enormous assistance. A case concerning the recovery of a burnt oral implant, connected to a bone fragment, among 2780 charred bone fragments, suspected to have belonged to a victim of homicide, is presented to demonstrate that dental implants and their site of bone integration represent a very precious element for personal forensic identification. Because of their morphological invariability in time and because of their morphologic uniqueness, they were used as evidence to associate unidentified human charred remains to a missing person where DNA analysis failed to do so. The case illustrates the fundamental contribution, not yet described in literature, given by the clinical aspects of tooth replacement with dental implants to a forensic discipline. Clinical practitioners should therefore be aware of the great importance of their work and of dental records in a forensic identification scenario.     

Dental hygiene students' matching accuracy when comparing antemortem dental radiographs and oral photographs to simulated postmortem WinID3® odontograms

Matching dental antemortem (AM) and postmortem (PM) data for human identification is especially challenging when the workforce is limited. Dental hygienists have served mass fatality incidents (MFIs) due to dental-related expertise. However, forensics within dental hygiene education and research on transferable skills is limited. This qualitative balance design study assessed senior dental hygiene students' match accuracy of simulated cases varying in dental identifiers based on AM full mouth series (FMS) radiographs and oral photographs to PM WinID3^® odontograms to demonstrate possible disaster victim identification (DVI) transferable skills gained during formal education. A convenience sample of senior dental hygiene students (n = 31) was presented information on WinID3^® interpretation, then presented with 5 mismatched cases and asked to visually interpret each to make 10 total matches; five based on AM FMS with simulated PM WinID3^® odontograms and five based on AM photographs with PM WinID3^® odontograms. Match accuracy scores ranged from 41.9% to 58.1% for cases with 1–10 identifiers, and 77.4% to 93.5% for cases with 11–40 identifiers. Accuracy when matching AM radiographs to PM odontograms versus AM photographs to PM odontograms was compared and revealed no statistical differences in match accuracy depending on image type (p = 0.388 to 1.000). Results of this pilot study suggests transferable match accuracy skills resulted from the participants' dental hygiene formal education. These baseline skills with additional specialized training support the rationale for dental hygienists serving on DVI teams. More research is needed in education and practice when preparing dental hygienists for forensic-based service.     

Disaster victim identification: new applications for postmortem computed tomography

Abstract:  Mass fatalities can present the forensic anthropologist and forensic pathologist with a different set of challenges to those presented by a single fatality. To date radiography has played an important role in the disaster victim identification (DVI) process. The aim of this paper is to highlight the benefits of applying computed tomography (CT) technology to the DVI process. The paper begins by reviewing the extent to which sophisticated imaging techniques, specifically CT, have been increasingly used to assist in the analysis of deceased individuals. A small scale case study is then presented which describes aspects of the DVI process following a recent Australian aviation disaster involving two individuals. Having grided the scene of the disaster, a total of 41 bags of heavily disrupted human remains were collected. A postmortem examination was subsequently undertaken. Analysis of the CT images of all body parts ( n  = 162) made it possible not only to identify and side differentially preserved skeletal elements which were anatomically unrecognizable in the heavily disrupted body masses, but also to observe and record useful identifying features such as surgical implants. In this case the role of the forensic anthropologist and CT technology were paramount in facilitating a quick identification, and subsequently, an effective and timely reconciliation, of body parts. Although this case study is small scale, it illustrates the enormous potential for CT imaging to complement the existing DVI process.     

Analysis of an ancestry using cremated old human remains from the Korean War victims

Analysis of DNA from burnt bone fragment is the very hard work for the human identification in forensic casework. In general, cremated bone with an artificial damage is more difficult to get an intact DNA than a singed one because of the chemical and biological drastic changes such as protein denaturation and destruction. In this study, we pursue the best technical approach for the minimal damage and the contamination of DNA from other factors in the preconditioning and the extraction process based on over 70 years old Korean War victim skeletal that was burnt and buried in Korean Peninsula. First of all, we removed the pollutant and the dust from the burnt bones using dental instruments, and then incubated with EDTA buffer at 25 ℃ to remove inhibitors such as calcium and mineral. In order to compare the DNA preservation ability between a pellet and a supernatant, samples are repeatedly tested to collect washed EDTA buffer several times to separate. Each of isolated materials is secondly cleaned with the organic extraction method using phenol and analyzed mtDNA sequence with the in-house method for the ancestry assay. The better discrimination ability was appeared in the supernatant than the pellet. Nevertheless, many of the forensic geneticists use a powdering method for getting more DNA, we applied EDTA buffer in the preconditioning step to eliminate every contamination. As a result, the contamination factor was efficiently removed and the ancestry was estimated as per the written information. Consequently, cremated bone is identified to belong in the D4 mtDNA haplogroup which is commonly reported in ethnic groups in Asia especially Korea. This is a preliminary study of a human identification over an ancestry analysis to give information against a mass disaster in a future. Through a higher process optimization and better analytical methods toward more remains, which are genetically difficult to analyze, will support to examine the identity of the post cremated remains.     

Identification of Human Remains by DNA Analysis of the Gastrointestinal Contents of Fly Larvae

Dipterous fly larvae (maggots) are frequently collected from a corpse during a criminal investigation. Previous studies showed that DNA analysis of the gastrointestinal contents of maggots might be used to reveal the identity of a victim. However, this approach has not been used to date in legal investigations, and thus its practical usefulness is unknown. A badly burned body was discovered with its face and neck colonized by fly larvae. Given the condition of the body, identification was not possible. Short tandem repeat (STR) typing was performed using the gastrointestinal contents of maggots collected from the victim and was compared to STR profiles obtained from the alleged father. The probability of paternity was 99.685%. Thus, this comparative DNA test enabled the conclusive identification of the remains. This is the first reported case of analysis of human DNA isolated from the gastrointestinal tract of maggots used to identify a victim in a criminal case.     

Fimag: The United Kingdom Disaster Victim/Forensic Identification Imaging System

Abstract:  Imaging is an integral diagnostic tool in mass fatality investigations undertaken traditionally by plain X-rays, fluoroscopy, and dental radiography. However, little attention has been given to appropriate image reporting, secure data transfer and storage particularly in relation to the need to meet stringent judicial requirements. Notwithstanding these limitations, it is the risk associated with the safe handling and investigation of contaminated fatalities which is providing new challenges for mass fatality radiological imaging. Mobile multi-slice computed tomography is an alternative to these traditional modalities as it provides a greater diagnostic yield and an opportunity to address the requirements of the criminal justice system. We present a new national disaster victim/forensic identification imaging system—Fimag—which is applicable for both contaminated and non-contaminated mass fatality imaging and addresses the issues of judicial reporting. We suggest this system opens a new era in radiological diagnostics for mass fatalities.