WinID2 versus CAPMI4: two computer-assisted dental identification systems

Disasters produce victims that require identification. Comparing antemortem and postmortem dental records provides an important means of identification. Computers have assisted this process. Currently, the principal computer programs are CAPMI4 and WinID2. The present study compared these programs on a sample of 100 simulated victims and 105 simulated postmortem fragments. CAPMI4 provided 48 correct matches and WinID2 provided 71 correct matches. In addition, comparisons were made within WinID2 to determine which of its three dental data sets was the most successful for suggesting correct matches.     

A new algorithm for use in computer identification

On 9 May 1987, a Soviet-made IL-62M Polish airliner, LOT Flight 5055, crashed, exploded, and burned, killing the crew and 183 passengers. A forensic science team from the Armed Forces Institute of Pathology, comprised of 6 dental officers, 3 forensic pathologists, and 3 medical photographers, worked in concert with the Polish forensic science team. The small number of antemortem records and the extreme fragmentation of the remains presented a new scenario for computer use. Typically, the Computer-Assisted Postmortem Identification (CAPMI) software is used to compare remains against an antemortem database. Results are listed by the number of tooth-to-tooth matches based on restorative or other characteristics or both. The Polish disaster confounded this approach to some degree, however, and suggested a reconsideration of the theory on which the sort is made, that is, that the cases with maximum number of matches to preexisting dental records would be the most likely identification (ID) match. A hypothesis was constructed that, if searches were accomplished for fragments with a minimum number of mismatches, the correct matches would appear higher in the rank order. Six antemortem records (that had all dental information) were sorted against one hundred and twelve postmortem fragmented records. The resulting report was reordered so that records were listed by minimum number of mismatches. There was significant improvement in rank placement for all of the records. Thus it was accepted that in the situation of highly fragmented remains a different sorting based on the number of mismatches is indicated. Programming changes to make this option available have been implemented in the new version of CAPMI.     

An Improved Version of a Tool Mark Comparison Algorithm

Chumbley et al. (2010) described a statistically based algorithm for comparing pairs of tool marks. They presented empirical evidence that the algorithm produces well‐separated similarity score values for “matching” and “non‐matching” pairs of tool marks. However, the algorithm has two substantial weaknesses. First, it is “uncalibrated” in the sense that error rates can be determined only through empirical investigation. Second, it relies on a randomized test and can lead to different similarity scores when the algorithm is repeatedly applied to the same pair of tool marks. We present an improved version of the procedure, which eliminates the randomized scores and yields more consistent and predictable error rate control. This is accomplished by replacement of a random sampling step from the original algorithm with a deterministic process. We demonstrate the improved algorithm and compare its performance to the original by applying to known “matching” and “non‐matching” pairs of tool marks.     

Dental characteristics of a large military population useful for identification

The number and complexity of dental restorations has decreased for younger Americans. Since the presence and extent of restorations are important data for forensic science identification purposes, the Computer-Assisted Postmortem Identification (CAPMI) system was used to assess the practical effect of the decreased selectivity expected as a result of improved dental health. Dental examination data from 7030 soldiers were recorded on optical mark read forms and entered into a database. The data were reorganized and analyzed to generate summary statistics about the incidence of each type of restoration (divided into 16 categories) for both anterior, posterior, upper, lower, and combined segments. Patients' ages ranged from 17 to 49 with a mean of 24 years 5 months. Sixty percent were from 18 to 25 years old. A characteristic is defined as any situation other than a virgin tooth; for example, extracted, missing, unerupted, or restored. The average subject had 7 dental characteristics with approximately 75% having 4 or more. Within the entire population, 9% had 32 unrestored teeth. 3.6% had only one characteristic. To test the selectivity and uniqueness of various combinations of dental characteristics, 363 simulations using the CAPMI system were made against the entire 7030 subject database. Sample records (33 per group) with 2, 3, 4, 5, 6, 7, 8, 9-11, 12-14, 15-18, and 19+ characteristics were chosen at random from the database and searches were made.(ABSTRACT TRUNCATED AT 250 WORDS)     

The bones in the Abbey: are they the murdered princes? A review of the evidence

In 1674, the skeletons of two children were found in the Tower of London. They were believed to represent the remains of the "Princes in the Tower" (who had disappeared in 1483), and were reinterred as such in Westminster Abbey. Popular belief and conventional historical tradition held that the princes had been murdered by their uncle, King Richard III, to clear his path to the throne. In 1933, the bones in the Abbey were disinterred and examined, with the conclusion that they were indeed those of the princes. One skull was also thought to show evidence of death by suffocation, supporting another feature of popular legend. Later reviews of the investigation, however, revealed significant errors and omissions. This report summarizes the inconsistencies present in the scientific record and suggests that reexamination of the remains with improved techniques in both carbon dating and forensic science would provide a much more accurate analysis, thus helping to clarify the historical record.     

Three-dimensional computer-assisted craniometrics: a comparison of the uncertainty in measurement induced by surface reconstruction performed by two computer programs

Digital investigation of anthropological material through computed tomography (CT) offers several new opportunities in morphometrics. However, an object measured with computer-assisted methods does not necessarily exactly match the original one. The scanning and surface reconstruction of the object induce some alterations, and data acquisition is prone to measurement uncertainty. The purpose of this research is to evaluate the intra- and inter-observers variations in medical CT scan measurements of a known-size phantom and two dry crania. Two software packages, AMIRA and Treatment and Increased Vision for Medical Imaging (TIVMI), which use different techniques of surface reconstructions, were compared. The mean difference between the measurements was lower for TIVMI, using an objective algorithm based on the half-maximum height (HMH) protocol in three dimensions (3D). AMIRA can induce up to a 4% error in known measurements and 5% uncertainty in dry skull measurements. This study emphasises the risk of object shape alteration in each step of its digitisation.     

The gander disaster: dental identification in a military tragedy

The authors record the contributions of dentistry to the identification of victims of one of the most significant disasters in aviation and U.S. military history--the December 1985 crash of a DC-8 charter airliner near Gander, Newfoundland (now known as Newfoundland and Labrador), Canada, which killed 248 Army personnel and 8 crewmembers. Most of the dental records of the military victims were destroyed in the crash, and, as a result, this loss hampered dental identification. Nevertheless, dental identification was the primary means of identification for many because a very high percentage of the bodies were severely burned and fragmented. Many phases of the U.S. identification efforts have been reported, but the dental-investigation aspects have been mentioned only in passing. Therefore, this article documents the dental team's organization, methodology, and a variety of remarkable problems that the team encountered.     

Confirmatory Factor Analysis of “Competence in Use of Firearms Questionnaire” Administered to City Police

The following research describes the psychometric characteristics of the Competence in Use of Firearms Questionnaire, administered to 139 city police agents from four municipalities of the southern region of Tenerife. The questionnaire was based partly on the framework of the competence model of Pereda and Berrocal (2001), and contained 101 items. We tested the construct validity of the questionnaire, its internal consistency, and its potential for practical application. The initial results suggested four factors, differing to some extent from the original model.     

Effect of Head Position on Facial Soft Tissue Depth Measurements Obtained Using Computed Tomography

Facial soft tissue depth (FSTD) studies employing clinical computed tomography (CT) data frequently rely on depth measurements from raw 2D orthoslices. However, the position of each patient's head was not standardized in this method, potentially decreasing measurement reliability and accuracy. This study measured FSTDs along the original orthoslice plane and compared these measurements to those standardized by the Frankfurt horizontal (FH). Subadult cranial CT scans (n = 115) were used to measure FSTDs at 18 landmarks. Significant differences were observed between the methods at eight of these landmarks (p < 0.05), demonstrating that high‐quality data are not generated simply by employing modern imaging modalities such as CT. Proper technique is crucial to useful results, and maintaining control over head position during FSTD data collection is important. This is easily and most readily achieved in CT techniques by rotating the head to the FH plane after constructing a 3D rendering of the data.     

Systematic differences in electropherogram peak heights reported by different versions of the GeneScan software

DNA profiling using STRs on the 310 and 3100 Genetic Analyzers routinely generates electropherograms that are analyzed with the GeneScan software available from the instrument's manufacturer, Applied Biosystems. Users have been able to choose from three different smoothing options that have been known to result in significant differences in the peak heights that are reported. Improvements in the underlying algorithm of the most recent version of the software also result in significant and somewhat predictable differences in peak height values. Laboratories that have performed validation studies using older versions of GeneScan should either reanalyze the data generated in those validation studies with the newest version of the software or otherwise take into consideration the systematically higher peak height values obtained as they begin following the recommendation of the manufacturer and use the new algorithm.     

Composite Machine Learning Algorithm for Material Sourcing,

This study developed a composite machine learning algorithm for attribution of materials of forensic interest (like ammonium nitrate) to original sources. k-nearest neighbor and random forest models were used for source elimination and classification, respectively, in a two-step, composite algorithm based on particle color, size/shape, and trace element concentration features. Novel approaches for simulation to supplement within-source reference features based on empirically measured multi-lot analyses, an improved hold-one-lot-out method for cross-validation, an assessment of the likelihood of the presence of a reference sample, fusion of the source probabilities from the respective classification models, and the calculation of metrics for assessing ensemble sourcing performance are described. Excellent sourcing predictions were obtained; the sourcing algorithm identified the correct source as the top choice 89% of the time, and the correct source was identified to be an average of 2.7 times more likely than the most likely incorrect source.     

烧骨组织形态变化及DNA技术在个体识别中的应用

烧骨在火灾、焚尸、交通、爆炸等案件和事故的检材中具有特殊的地位。通过对不同条件焚烧下烧骨组织形态及DNA变化规律的研究,可为法医实践中烧骨的种属鉴定、性别及年龄判定提供准确的依据和标准,同时可利用残存的基因位点对烧骨残块进行个体识别和同一认定。烧骨DNA的提取方法及检测技术也在不断探索和改进。本文对烧骨在形态学、组织学和分子生物学水平研究进展以及烧骨评测的方法、技术进行概述,旨在为法医实践及进一步研究提供新的方法和思路。     

Three‐Dimensional Comparative Analysis of Bitemarks*

Abstract: Historically, the inability to accurately represent bitemarks and other wound patterns has limited their evidentiary value. The development of the ABFO #2 scale by Krauss and Hyzer enabled forensic odontologists to correct for most photographic plane distortions. The technique presented here uses the ABFO #2 scale in conjunction with the evolving technologies of laser scanners and comparative software commonly used by the automobile industry for three‐dimensional (3D) analysis. The 3D software comparison was performed in which measurements were analyzed of the normal distance for each point on the teeth relative to the bitemarks. It created a color‐mapped display of the bitemark model, with the color indicating the deviation at each point. There was a correlation between the bitemark and the original teeth.     

The primary investigation of material evidence and the evaluation of its suitability for expert biological identification by genomic "dactyloscopy"

Use of DNA "fingerprinting" method for biological analysis of material evidences exhibit new potentials for making concrete expert conclusions. But such expertise is time consuming and difficult to perform that's why it is important to evaluate fitness of expert material for DNA fingerprinting at early stages of object investigation. Method of preliminary treatment of objects sent for DNA fingerprint expertise in case of sexual assault is suggested and tested. This method allows one to evaluate objects easily from the standpoint of possibility to perform such investigation.     

The impact of a change in commitment procedures on the character of involuntary psychiatric patients

The statutory requirements for involuntary civil psychiatric confinement have become increasingly restrictive. In the jurisdiction under investigation, patients were originally admitted under an Order to Apprehend (OTA) procedure simply on the petition of two affiants who indicated the patient was in need of care. A newly elected judge instituted changes requiring affiants to claim the subject was "dangerous" to self or others and asking for a clinical assessment and recommendation before signing the petitioned request for involuntary confinement. It might be expected that the more restrictive procedures would have produced a population of more assaultive patients. A study of petitions signed under in the earlier (N = 133) and later, more restrictive (N = 218) procedures indicated that the proportion of assaultive or dangerous patients was virtually identical. Further investigation, using hospital data an OTA patients from this area in both time periods, suggested that while patients were not more assaultive, they appeared to be more seriously ill or psychiatrically impaired. Apparently, movement to a dangerousness standard that allows clinical discretion in interpreting its presence may result in involuntary commitments for more seriously ill, although not necessarily more assaultive, patients.     

Accounting for Projection Bias in Models of Delinquent Peer Influence: The Utility and Limits of Latent Variable Approaches

Objectives

Projection effects have been shown to bias respondent perceptions of peer delinquency, but network data required to measure peer delinquency directly are unavailable in most existing datasets. Some researchers have therefore attempted to adjust perceived peer behavior measures for bias via latent variable modeling techniques. The present study tested whether such adjustments render perceived peer coefficients equal to direct peer coefficients, using original data collected from 538 young adults (269 dyads).

Methods

After first replicating projection effects in our own data and examining the degree to which measures of personal, perceived peer, and direct peer violence represent empirically distinct constructs, we compared coefficients derived from two alternative models of personal violence. The first model included an error-adjusted latent measure of perceived peer violence as a predictor, whereas the second substituted a latent measure of directly-assessed, peer-reported violence.

Results

Results suggest that personal, perceived peer, and direct peer measures each reflect fundamentally separate constructs, but call into question whether latent variable techniques used by prior researchers to correct for respondent bias are capable of rendering perceived peer coefficients equal to direct peer coefficients.

Conclusions

Research cannot bypass the collection of direct peer delinquency measures via latent variable modeling adjustments to perceived peer measures, nor should models of deviance view perceived peer and direct peer measures as alternative measures of the same underlying construct. Rather, theories of peer influence should elaborate and test models that simultaneously include both peer measures and, further, should attempt to identify those factors that account for currently unexplained variance in perceptions of peer behavior.     

The reliability of forensic osteology--a case in point. Case study

The medico-legal investigation of skeletons is a trans-disciplinary effort by forensic scientists as well as physical anthropologists. The advent of DNA extraction and amplification from bones and teeth has led to the assumption that morphological assessment of skeletal remains might soon become obsolete. But despite the introduction and success of molecular biology, the analysis of skeletal biology will remain an integral part of the identification process. This is due to the fact, that the skeletal record allows relatively fast and accurate inferences about the identity of the victim. Moreover, a standard biological profile may be established to effectively narrow the police investigator's search parameters. The following study demonstrates how skeletal biology may collaborate in the forensic investigation and support DNA fingerprinting evidence.In this case, the information gained from standard morphological methods about the unknown person's sex, age and heritage immediately led the police to suspect, that the remains were that of a young man from Vietnam, who had been missing for 2.5 years. The investigation then quickly shifted to prove the victim's identity via DNA extraction and mtDNA sequence analysis and biostatistical calculations involving questions of kinship [4].     

Accuracy and Reproducibility of Bullet Trajectories in FARO Zone 3D

With three-dimensional (3D) laser scanning technology and software packages, the practice of documenting and measuring bullet trajectories has benefited from greater accuracy and reproducibility. This study investigated the accuracy and reproducibility of the bullet trajectory tools in the software package, FARO Zone 3D (FZ3D). Twelve participants were provided laser scanner data for 21 bullet trajectories on drywall panels with impact angles between 25° and 90°. When the impact plane was manually aligned by the operator, 75% of the absolute errors were within 0.91° and 0.98° for the azimuth and vertical angles, respectively. The vertical angle improved to 0.47° when impact plane alignment was taken with respect to gravity (no operator influence). Thus, manual alignment is shown to be subject to greater error than alignment with gravity. However, this study shows that the accuracy and reproducibility of the FZ3D bullet trajectory tools to be comparable with previous research studies.     

"I am flying to the stars"--suicide by aircraft in Germany

In 2006, 67 persons were killed in aircraft accidents in Germany and involving German aircrafts abroad. In spite of extensive investigation of each aircraft accident, there are no reliable data as to the number of suicides by aircraft. We report on a 50-year-old man who committed suicide by willfully crashing his Beech "Sierra" aircraft minutes after take off from an airport close to the town of Rendsburg, Germany. Before killing himself, the intoxicated pilot had sent an SMS announcing his suicide plans to a friend. The findings of the medico-legal investigation and the results of a review of aircraft accident reports by the German Federal Bureau of Aircraft Accidents Investigation (BFU) regarding suicidal plane crashes are presented.     

Forensic dental training in the dental school curriculum

This article reviews the literature regarding forensic education in the dental school curriculum and describes an exercise in forensic identification of victims of a mass casualty. Radiographs were made of dentate human cadavers in the gross anatomy laboratory at the Southern Illinois School of Dental Medicine. The jaws were then removed to provide "wet specimens" for the exercise. Several restorations were performed on the cadaver teeth, after which radiographs of the dissected jaws were made. One author wrote up mock dental records for each of the victims. These records included the first set or "premortem" radiographs. Students participating in the exercise were provided with a plane crash scenario, the dental records of the passengers on the manifest, the dissected jaws, and the second set or "postmortem" radiographs. Students were expected to form three teams. The first two teams evaluated the ante-mortem and postmortem dental records. The third team compared the ante-mortem and postmortem records to arrive at identification. The purpose of the exercise was twofold. It introduced dental students to forensic dentistry and emphasized the need for complete and accurate record keeping in the dental office. Several factors lessened the realism of the exercise and made it difficult to reproduce in the future. These included the uniformity of the dental records and the destruction of cadaver material following the exercise.