Personal identification and missing persons initiatives in Santa Catarina state,Brazil: forensic perspectives from 2019 to 2021

Santa Catarina is a small, developed, and relatively safe state in South Brazil. Despite having positive social economic indicators, it still faces multiple challenges regarding forensic practices for personal identification. The objective of this paper is to discuss the recent advances and current challenges in the region, from the perspectives of anthropological and dental postmortem human identification, missing persons, and disaster victim identification (DVI) from 2019 to 2021. The recent creation of a Forensic Anthropology Sector (SAF) in the state’s official forensic institution (Polícia Científica—PCI) has significantly improved identification of unidentified remains and optimised resources available for DNA analysis. However, SAF is still quite understaffed, which negatively affects the recovery of skeletal material, its preparation, and the time needed for filing reports. Santa Catarina has passed legislation for missing persons in 2015, 4 years prior to the sanction of federal laws implementing the national policy for the disappeared. Nonetheless, a lack of integration between stakeholders remains a problem that PCI has tried to circumvent with the Conecta Programme, a multidisciplinary and integrated initiative between families of the missing persons, police agencies, and the Public Ministry. The programme aims to collect not only reference DNA samples, but also relevant anthropological and dental data. It also offers facial progression services in cases of disappearances that occurred many years ago. Despite a history of disasters in the state, PCI still needs to implement international DVI standards at an institutional level. Recent training on Phase 1 DVI procedures, integrated with other responding institutions, indicates better preparation for future disasters. There are many challenges ahead for Santa Catarina’s forensic institution and professionals that have yet to be addressed, but the overall situation on routine personal identification, missing persons initiatives, and DVI has improved over the last 2 years.     

The need for a complete dental autopsy of unidentified edentulous human remains

In December 2017, a decomposed unidentified body was found near the river Tronto in Teramo, Italy. The corpse was found without any identifying documents or specific personal belongings, except for a packet of cigarettes. The medical examiner determined a gastric perforation from the intake of hydrochloric acid to be the cause of death. A jar of muriatic acid found near the body led to suicide being considered the manner of death. The Penal Court in Teramo appointed two forensic odontologists to complete the postmortem assessment and collect dental data for personal identification. The corpse was found wearing a complete set of upper and lower dentures. The dental autopsy and 42 periapical X-ray images helped generate a biological profile of a man totally edentulous with upper and lower dentures, as well as an osteosynthesis with two plates and screws in the left ascending ramus of the mandible. In March 2018, the sister of a missing person reported the disappearance of her brother, and a presumptive identification was performed through visual recognition of the decomposed body. The sister confirmed the presence of two dentures and the location of the maxillo-facial surgery for the treatment of the fractured mandible. A complete dental autopsy was able to establish his identity without any DNA comparison needed. This case highlights the importance of performing a complete dental autopsy inclusive of dental radiographs, and its value in the identification of all unknown human remains even when totally edentulous.A complete dental autopsy should be performed in all cases of human identification.

Keypoints

• Despite a corpse being edentulous, a complete dental autopsy can still be useful.
• Dental radiographs, such as bitewings, periapical images, panoramic radiographs, and CT scans, are recommended in all identification autopsies.

     

Fragment analysis in forensic anthropology

Anthropological analysis of fragmentary evidence can be challenging but diverse methods allow substantial information to be gleaned. Scanning electron microscopy/energy dispersive X-ray spectroscopy enables determination if bone and/or tooth tissue is present. Protein radioimmunoassay or DNA analysis can establish the species present. Histological analysis can assist in species determination and reveal information about thermal changes. Radiocarbon analysis with special reference to the modern bomb-curve can clarify the postmortem interval. Anthropologists should also be aware that DNA analysis not only can enable positive identification but assist in the evaluation of sex and age at death.     

Accuracy of developing tooth length as an estimate of age in human skeletal remains: the deciduous dentition

Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development.     

Assessment of the forensic application of 50 Y-STR markers in a large pedigree

Short tandem repeats on the Y chromosome (Y-STRs), characterized by paternal inheritance, are valuable in forensic practice. Notably, the potential application of Y-STRs in pedigrees should be drawn upon, especially in China’s surname-concentrated natural villages. The study focused on 50 Y-STRs, including 13 rapidly mutating (RM) Y-STRs that largely constitute the current Y-STR commercial kits, and determined the differences in these Y-STRs between branches in a large pedigree and the discriminatory power of these haplotypes in different units for male relatives. As indicated in the results, 14 inconsistencies were observed at 9 Y-STRs between 10 father-son pairs. In addition, these 50 Y-STR haplotypes discriminated 10 out of 47 father-son pairs, 106 of 148 cousin pairs, 70 of 119 uncle-nephew pairs, 17 of 39 brother pairs, and 14 out of 33 grandfather-grandson pairs in a large pedigree. The RM Y-STR set is able to differentiate close male relatives in a large pedigree.     

Haptics in forensics: The possibilities and advantages in using the haptic device for reconstruction approaches in forensic science

Non-invasive documentation methods such as surface scanning and radiological imaging are gaining in importance in the forensic field. These three-dimensional technologies provide digital 3D data, which are processed and handled in the computer. However, the sense of touch gets lost using the virtual approach. The haptic device enables the use of the sense of touch to handle and feel digital 3D data. The multifunctional application of a haptic device for forensic approaches is evaluated and illustrated in three different cases: the representation of bone fractures of the lower extremities, by traffic accidents, in a non-invasive manner; the comparison of bone injuries with the presumed injury-inflicting instrument; and in a gunshot case, the identification of the gun by the muzzle imprint, and the reconstruction of the holding position of the gun.The 3D models of the bones are generated from the Computed Tomography (CT) images. The 3D models of the exterior injuries, the injury-inflicting tools and the bone injuries, where a higher resolution is necessary, are created by the optical surface scan.The haptic device is used in combination with the software FreeForm Modelling Plus™ for touching the surface of the 3D models to feel the minute injuries and the surface of tools, to reposition displaced bone parts and to compare an injury-causing instrument with an injury.The repositioning of 3D models in a reconstruction is easier, faster and more precisely executed by means of using the sense of touch and with the user-friendly movement in the 3D space. For representation purposes, the fracture lines of bones are coloured. This work demonstrates that the haptic device is a suitable and efficient application in forensic science. The haptic device offers a new way in the handling of digital data in the virtual 3D space.     

Age estimation of individuals aged 5–23 years based on dental development of the Indonesian population

Dental development can be used to estimate age for forensic purposes. However, most of the currently available methods are less reliable for the Indonesian population due to population variability. This study presents a new method and evaluates other methods that utilize dental development to estimate the age of Indonesian people. Panoramic radiographs of 304 young Indonesian people aged 5–23 years old were analysed for deciduous tooth root resorption, permanent tooth calcification, and eruption. The extent of tooth root resorption was determined based on AlQahtani’s modified Moorrees et al. method. Tooth calcification was classified based on a modified Demirjian et al. method. Tooth eruption was evaluated based on AlQahtani’s modified Bengston system. The sequence of tooth root resorption, and permanent tooth calcification and eruption were grouped into 19 age categories (from 5–23 years old) in an atlas. The differences between males and females, between maxillary and mandibular teeth, and between right and left teeth were also analysed. There were minimal significant differences of tooth development between males and females, and between the right and left teeth (P > 0.05), while the maxillary and mandibular dental development was significantly different (P < 0.05). The newly developed atlas showed the development of the right side of maxillary and mandibular tooth of combined sex of Indonesian population. Another 34 panoramic radiographs of known-age and sex individuals from Indonesia were assessed using the newly developed Atlas of Dental Development in the Indonesian Population, Ubelaker’s Dental Development Chart, The London Atlas of Human Tooth Development and Eruption by AlQahtani, and the Age Estimation Guide-Modern Australia population by Blenkin-Taylor. Accuracy was assessed by comparing estimated age to actual chronological age using the Bland-Altmand test. Results show that the smallest range of error was found in the Atlas of Dental Development in the Indonesian Population (−0.969 to 1.210 years), followed by The London Atlas of Human Tooth Development and Eruption by AlQahtani (−2.013 to 1.990 years), the Age Estimation Guide-Modern Australia population by Blenkin-Taylor (−2.495 to 2.598 years), and the Dental Development Chart by Ubelaker (−2.960 to 3.289 years). These findings show that the Atlas of Dental Development constructed in this study performs better than the other three methods and presents greater accuracy of age estimation in the Indonesian population.

Key points

• Dental development such as deciduous tooth root resorption, permanent tooth calcification, and tooth eruption can be used to estimate age for forensic purposes.
• The development of the teeth are influenced by genetic, ethnicity, and sex, therefore an age estimation method must be constructed based on the same population.
• There were minimal significant differences in tooth development between male and female, and between right and left teeth, but there was significant difference between maxillary and mandibular teeth.
• The Atlas of Dental Development in the Indonesian Population constructed in this study allowed more accurate age estimation of the Indonesian sample than the other methods tested.

Supplemental data for this article are available online at https://doi.org/10.1080/20961790.2021.1886648.     

A review of experimental design in forensic taphonomy: moving towards forensic realism

Forensic taphonomy as a discipline requires standardization to satisfy Daubert criteria for scientific data to be admissible in court. In response, there has been a shift towards quantification of methodology and estimating the postmortem interval. Despite these advances, there are still biases and limitations within the discipline not explicitly addressed in the early stages of experimental design nor in final published works. In this article, unresolved debates with respect to the conductance and reporting of forensic taphonomic research are reviewed, beginning with the nature of experimental cadavers, human or animal analogues and their body size, and second, the forensic realism of experimental setups, specifically with respect to caging, clothing and number of carcases. Pigs, albeit imperfect, are a good model to gain a general idea of the trends that may be seen in humans in subsequent validation studies in facilities where human donors are available. To date, there is no consensus among taphonomists on the extent of the effect that body mass has on decomposition progression. More research is required with both human cadavers and non-human analogues that builds on our current knowledge of forensic taphonomy to answer these nagging questions. This will enable the discipline to make the reliable assumption that pigs and donor decomposition data can be applied to homicide cases. A suite of experimental design aspects is suggested to ensure systematic and standardized data collection across different biogeoclimatic circumstances to identify and quantify the effects of potential confounding variables. Such studies in multiple, varied biogeographic circumstances with standardized protocols, equipment and carrion will facilitate independent global validation of patterns. These factors are reviewed to show the need for adjustments in experimental design to ensure relevance and applicability of data within locally realistic forensic situations. The initiation of a global decomposition data network for forensic taphonomists is recommended.

Key points

• Pigs are a valuable, albeit imperfect, proxy for human decomposition studies.
• There are few or conflicting data on effects of carcase size, carrion ecology, exclusion cages and scavengers.
• We recommend single, clothed, uncaged carcases for baseline research to reflect regionally specific forensic casework.

     

A technique to capture, analyze, and quantify anterior teeth rotations for application in court cases involving tooth marks

Anterior teeth within the human dentition have a specific numerical rotation value. Bite marks show an array of angled indentations, abrasions, microlacerations, and contusions. These marks generally represent the incisal surfaces of the suspect's dentition reflecting the rotation values of the teeth in the dental arch. This study described a method for capturing and analyzing anterior dental rotations. The rotations of individual anterior teeth within the study population were categorized as common, uncommon, and very uncommon according to Allen's classification. In the absence of a large number of incisal patterns present in a bite mark, a single but heavily weighted tooth rotation could be of equal discriminatory potential to several common rotation values. No prevalence studies quantifying individual tooth rotations are available. The measurement of each individual tooth rotation together with its individual discrimination potential will enhance the evaluation of the concordant features observed in bite marks.     

An inter-laboratory study of DNA-based identity,parentage and species testing in animal forensic genetics

The probative value of animal forensic genetic evidence relies on laboratory accuracy and reliability. Inter-laboratory comparisons allow laboratories to evaluate their performance on specific tests and analyses and to continue to monitor their output. The International Society for Animal Genetics (ISAG) administered animal forensic comparison tests (AFCTs) in 2016 and 2018 to assess the limitations and capabilities of laboratories offering forensic identification, parentage and species determination services. The AFCTs revealed that analyses of low DNA template concentrations (≤300 pg/µL) constitute a significant challenge that has prevented many laboratories from reporting correct identification and parentage results. Moreover, a lack of familiarity with species testing protocols, interpretation guidelines and representative databases prevented over a quarter of the participating laboratories from submitting correct species determination results. Several laboratories showed improvement in their genotyping accuracy over time. However, the use of forensically validated standards, such as a standard forensic short tandem repeat (STR) kit, preferably with an allelic ladder, and stricter guidelines for STR typing, may have prevented some common issues from occurring, such as genotyping inaccuracies, missing data, elevated stutter products and loading errors. The AFCTs underscore the importance of conducting routine forensic comparison tests to allow laboratories to compare results from each other. Laboratories should keep improving their scientific and technical capabilities and continuously evaluate their personnel’s proficiency in critical techniques such as low copy number (LCN) analysis and species testing. Although this is the first time that the ISAG has conducted comparison tests for forensic testing, findings from these AFCTs may serve as the foundation for continuous improvements of the overall quality of animal forensic genetic testing.     

A test of the differential accuracy of the maxillary versus the mandibular dentition in age estimations of immature skeletal remains based on developing tooth length

Liversidge and colleagues developed a method for predicting the age of immature skeletal remains based on the length of developing teeth. This quantitative method combines dental data from both jaws, except for the permanent lateral incisor, and because there are reasons to suspect that these two types of data are not identical and should not be combined, it raises concerns regarding the accuracy of the technique when applied differently to each jaw. In this study, the differential accuracy of the method was test when applied to the maxillary and mandibular dentition. The test sample is comprised of 57 Portuguese subadult skeletons of known age at death. Results suggest an overall high consistency between estimates obtained from both jaws, but for the permanent dentition only. In the deciduous dentition the age estimates obtained from the maxillary teeth tend to be greater than the age estimates obtained from the mandibular pair, and the differences are significant for the incisors and canine. Additionally, ages obtained from the maxillary deciduous canine also differ significantly from true chronological age. In the permanent dentition there were no differences between the ages provided by both jaws but both the maxillary and mandibular second molars show a significant tendency to underestimate true chronological age. Although this study cannot validate completely the method presented by Liversidge and colleagues, it does provide an important test to its accuracy and calls for further research into its overall performance, particularly with respect to the results obtained from both jaws.     

Forensic data management and database systems in forensic investigations for cases of missing and unidentified persons in Brazil

Forensic investigations, especially those related to missing persons and unidentified remains, produce different types of data that must be managed and understood. The data collected and produced are extensive and originate from various sources: the police, non-governmental organizations (NGOs), medical examiner offices, specialised forensic teams, family members, and others. Some examples of information include, but are not limited to, the investigative background information, excavation data of burial sites, antemortem data on missing persons, and postmortem data on the remains of unidentified individuals. These complex data must be stored in a secured place, analysed, compared, shared, and then reported to the investigative actors and the public, especially the families of missing persons, who should be kept informed of the investigation. Therefore, a data management system with the capability of performing the tasks relevant to the goals of the investigation and the identification of an individual, while respecting the deceased and their families, is critical for standardising investigations. Data management is crucial to assure the quality of investigative processes, and it must be recognised as a holistic integrated system. The aim of this article is to discuss some of the most important components of an effective forensic data management system. The discussion is enriched by examples, challenges, and lessons learned from the erratic development and launching of databases for missing and unidentified persons in Brazil. The main objective of this article is to bring attention to the urgent need for an effective and integrated system in Brazil.     

Highly efficient and automated extraction of DNA from human remains using a modified EZ1 protocol

Bones and teeth often represent the only sources of DNA available for identifying human remains. DNA in bones and teeth is generally better preserved than that in soft tissues because of the presence of hard connective tissue with a high level of calcium. Because of the extensive mineralisation, the choice of an efficient DNA extraction procedure is important to minimise the sampling of a high level of minerals and to remove polymerase chain reaction (PCR) inhibitors. Some protocols are available for DNA extraction from bones and teeth as part of the Qiagen EZ1 DNA Investigator Kit using the EZ1 Advanced XL automated purification platform. To improve the efficiency of DNA extraction from skeletal remains, the present study focuses on a modification to these already available protocols. In this study, different bones and teeth collected between 1 and 50 years after death were subjected to DNA extraction using the standard EZ1 protocol, a supplementary protocol, and a modified protocol. The modified approach included a decalcification step, whereas the Qiagen protocols worked directly on non-decalcified powder. In all three procedures, 150 mg samples were used for DNA extraction. We evaluated the quantity of DNA recovered from samples, the presence of any PCR inhibitors co-extracted, the level of DNA degradation, the quality of short tandem repeat (STR) profiles, and the reproducibility of the modified procedure. When compared with the other protocols, the modified protocol resulted in the best recovery of DNA that was free of PCR inhibitors. Additionally, the STR profiles were reliable and of high quality. In our opinion, the decalcification step increases DNA recovery by softening tissues, which allows lysis solutions to act more effectively. Furthermore, the use of two lysis solutions and the variation added to the EZ1 purification step allow for DNA recovery with quality and quantity superior to those of the previously available Qiagen-based protocols. These findings may be helpful solutions to the problems commonly encountered when dealing with difficult samples, such as bones and teeth.

Key points

• Bones and teeth often represent the only sources of DNA for identifying human remains.
• The choice of an efficient DNA extraction procedure is important for maximizing DNA recovery and removing PCR inhibitors.
• This study focuses on modifications to the previously available Qiagen-based protocols.
• The modified protocol enabled the best recovery of DNA, and both quality and quantity were superior to those of the previously available Qiagen-based protocols.
• The STR profiles obtained from samples extracted using the modified protocol were reliable and of high quality.

     

Contributions of anatomy to forensic sex estimation: focus on head and neck bones

This study sought to provide an up-to-date review of the importance of anatomy to human identification,focusing on the usefulness of anatomical knowledge about the head and neck bones and teeth to sex estimation in routine forensic anthropology methods.A detailed search of osteology applications in forensic sex estimation was conducted through the electronic databases for the 10 years prior to July 2020.Relevant articles and classic literature on the subject were gathered and outlined in this review.Among the available literature,several metric analyses showed accuracy superior to 80%in sexual diagnosis.Angles measured from the inclination of glabellae and analysis of the external frontal bone surface through three-dimensional computer-aided design emerge as reliable cranial indexes for sex estimation.in the mandible,the condylar and coronoid height,bigonial width,and condylion-gonion distance express significant sexual dimorphism.Measurements of the canine are the best option for sex estimation using teeth,as well as the thickness of the dentine or enamel of incisors.The axis vertebra surpasses other neck bones for sex estimation due to its atypical shape and the presence of the odontoid process.Metric analyses based on anatomy can provide reliable accuracy in sexual diagnosis.Adequate training and anatomical knowledge can reduce bias and interobserver differences,and the use of three-dimensional models and computed tomography images can enhance the accuracy of these methods for sex estimation.However,every method should be validated before being applied to a different population.     

The development and application of a diatom-based quantitative reconstruction technique in forensic science

Diatoms are a group of unicellular algae that have been recorded and classified for over 200 years and have been used in a range of applications in forensic science. We have developed a quantitative diatom-based reconstruction technique to confirm drowning as a cause of death and localize the site of drowning in two recent, high-profile, case studies. In both case studies we collected diatom samples from the local and/or regional area to act as a control in the examination of diatom assemblages associated with lungs and clothing. In Case Study 1 the modern analog technique suggested that all lung and clothing samples have statistically significant similarities to control samples from shallow water habitats. In Case Study 2, the analog matching suggested that the majority of lung samples show a statistically significant relationship to samples from a pond, indicating that this was the drowning medium.     

螺旋CT三维重建在肋骨骨折法医临床鉴定中的应用

目的探讨螺旋CT三维重建评价肋骨骨折在法医临床中应用价值。方法收集肋骨骨折35例,分别采用X线摄片、CT扫描及螺旋CT三维重建检查。结论35例检查都取得清晰的立体图像,且可以消除周围组织结构,单独观察肋骨骨折情况。结果:螺旋CT三维重建在肋骨骨折的诊断、法医临床学中有较高的价值。     

Antemortem dental records: attitudes and practices of forensic dentists

This study was designed to provide insight concerning the attitudes and practices of forensic dentists regarding antemortem dental records reviewed for purposes of dental identification. Forensic dentists were invited to participate in a 10 item survey. The majority of the respondents reported a considerable amount of experience in dental identifications of the deceased. Sixty-six percent reported having suspected dental negligence or fraud in their antemortem record reviews. Only 17% believe that a forensic dentist should report suspected dental negligence, while 31% agree that dental fraud should be reported. Their response to additional issues addressed in the study suggests diversity in the practices and attitudes of forensic dentists in the use of antemortem dental records. In conclusion, opening a dialogue among practicing forensic dentists may lead to a standardized set of recommendations by the appropriate societies in the forensic dental community.