Validation of a standard forensic anthropology examination protocol by measurement of applicability and reliability on exhumed and archive samples of known biological attribution.
Forensic Sci Int. 2017 Sep 07;279:241-250
Authors: Francisco RA, Evison MP, Costa Junior MLD, Silveira TCP, Secchieri JM, Guimarães MA
Forensic anthropology makes an important contribution to human identification and assessment of the causes and mechanisms of death and body disposal in criminal and civil investigations, including those related to atrocity, disaster and trafficking victim identification. The methods used are comparative, relying on assignment of questioned material to categories observed in standard reference material of known attribution. Reference collections typically originate in Europe and North America, and are not necessarily representative of contemporary global populations. Methods based on them must be validated when applied to novel populations. This study describes the validation of a standardized forensic anthropology examination protocol by application to two contemporary Brazilian skeletal samples of known attribution. One sample (n=90) was collected from exhumations following 7-35 years of burial and the second (n=30) was collected following successful investigations following routine case work. The study presents measurement of (1) the applicability of each of the methods: used and (2) the reliability with which the biographic parameters were assigned in each case. The results are discussed with reference to published assessments of methodological reliability regarding sex, age and-in particular-ancestry estimation.
PMID: 28926780 [PubMed – as supplied by publisher]
Strength of linguistic text evidence: A fused forensic text comparison system.
Forensic Sci Int. 2017 Jul 08;278:184-197
Authors: Ishihara S
Compared to other forensic comparative sciences, studies of the efficacy of the likelihood ratio (LR) framework in forensic authorship analysis are lagging. An experiment is described concerning the estimation of strength of linguistic text evidence within that framework. The LRs were estimated by trialling three different procedures: one is based on the multivariate kernel density (MVKD) formula, with each group of messages being modelled as a vector of authorship attribution features; the other two involve N-grams based on word tokens and characters, respectively. The LRs that were separately estimated from the three different procedures are logistic-regression-fused to obtain a single LR for each author comparison. This study used predatory chatlog messages sampled from 115 authors. To see how the number of word tokens affects the performance of a forensic text comparison (FTC) system, token numbers used for modelling each group of messages were progressively increased: 500, 1000, 1500 and 2500 tokens. The performance of the FTC system is assessed using the log-likelihood-ratio cost (Cllr), which is a gradient metric for the quality of LRs, and the strength of the derived LRs is charted as Tippett plots. It is demonstrated in this study that (i) out of the three procedures, the MVKD procedure with authorship attribution features performed best in terms of Cllr, and that (ii) the fused system outperformed all three of the single procedures. When the token length is 1500, for example, the fused system achieved a Cllr value of 0.15. Some unrealistically strong LRs were observed in the results. Reasons for these are discussed, and a possible solution to the problem, namely the empirical lower and upper bound LR (ELUB) method is trialled and applied to the LRs of the best-achieving fusion system.
PMID: 28735218 [PubMed – as supplied by publisher]
Zopiclone concentrations in oral fluid and blood after, administration of therapeutic doses of zopiclone.
Forensic Sci Int. 2017 Jul 13;278:177-183
Authors: Hjelmeland K, Gustavsen I, Øiestad EL, Øiestad ÅML, Høiseth G, Mørland J
PURPOSE: Little is known about the relationship between concentrations in oral fluid (OF) and blood for the widely prescribed hypnotic drug zopiclone. The purpose of this study was to investigate the usefulness of OF zopiclone concentrations to predict blood zopiclone concentrations in order to introduce OF testing as an alternative to more cumbersome blood testing.
METHODS: 16 healthy young male volunteers received capsules of either 5 or 10mg zopiclone on two different study days separated by at least one week. Blood and OF were collected simultaneously at baseline and 9 times after intake of zopiclone on each study day. In addition an OF sample was collected 24-81h after intake. Lunch was served between samples taken 2.5 and 3.5h after intake. All samples were analysed for zopiclone, and the cut-off was 10ng/ml in blood and 0.2ng/ml in OF-buffer mixture.
RESULTS: Zopiclone was detected in all OF samples during the study day. After 24-81h, all subjects were also positive for zopiclone in OF, except from three subjects ingesting the 5mg dose. In a single case zopiclone was detected in a baseline OF sample 14days after intake on an earlier study day. Zopiclone was detected in both OF and blood in 231 OF/blood pairs, and a significant but weak correlation between OF and blood concentration was seen (R(2) of 0.30). The median (range) zopiclone OF/blood concentration ratio (ZOBCR) for all samples were 3.3 (0.8-18). The ZOBCR decreased when the OF volume increased. After 30 of 31 given doses of zopiclone, the ZOBCR was higher in samples collected before lunch than samples collected after lunch.
DISCUSSION: Vast intra- and interindividual differences in ZOBCR were found, and the correlation between OF and blood concentration was less pronounced than reported in former studies. In accordance with earlier studies we found a negative correlation between ZOBCR and OF volume. The ZOBCR decreases in relation to recent intake of a meal, probably because stimulated saliva production causes “dilution” of saliva. OF zopiclone concentration appeared unsuitable for estimation of blood zopiclone concentration. Due to long detection time, analysis of zopiclone in OF might be useful to detect non-recent, previous intake.
PMID: 28735217 [PubMed – as supplied by publisher]
The accuracy of the anatomical method for stature estimation in Black South African females.
Forensic Sci Int. 2017 Jun 12;:
Authors: Brits D, Manger PR, Bidmos MA
The anatomical method is considered the most accurate stature estimation method, but investigation has shown that it continuously underestimates stature. This underestimation is believed to be related to the use of universal soft tissue correction factors. Therefore, the aim of this study was to assess the accuracy of the soft tissue correction factors in a living population of Black South African females and to subsequently calculate a new soft tissue correction factor, specific for stature estimation in this population group. Thirty Black South African adult females voluntarily participated in this study and underwent a full body Magnetic Resonance Imaging (MRI) scan. Living stature was measured with a stadiometer and total skeletal height (TSH) was calculated from the MRI measurements. Stature was estimated from the TSH of each participant using Fully’s (1956) , Raxter et al.’s (2006)  and Bidmos and Manger’s (2012)  methods. Results indicated strong, statistically significant positive correlations between living and estimated statures, however, paired t-tests revealed that living stature was significantly underestimated using Fully’s and Raxter et al.’s methods, while the method by Bidmos and Manger significantly overestimated stature. A lack of statistically significant correlations between soft tissue correction factors and the total skeletal height was found. Likewise, an absence of statistically significant correlations between age and the estimation error, with and without age adjustments were also observed. A new soft tissue correction factor, specific for stature estimation in Black South African females was calculated. The newly proposed regression equation presented improved stature estimation accuracies for this population group.
PMID: 28698061 [PubMed – as supplied by publisher]
Voyaging into the third dimension: A perspective on virtual methods and their application to studies of juvenile sex estimation and the ontogeny of sexual dimorphism.
Forensic Sci Int. 2017 Jun 26;278:32-46
Authors: Wilson LAB, Humphrey LT
In contrast to the well-established and highly accurate morphological methods available for sexing adult skeletons, juvenile sex estimation is widely recognised as a difficult task that faces a series of challenges. The acquisition of 3D data, and construction of 3D models from volume or surface scans, has become increasingly common in forensic sciences, and these data offer considerable opportunity for the development and refinement of methods in sex estimation. The suitability and potential of virtual methods for juvenile sex estimation are evaluated with the aims of identifying (1) the benefits and challenges associated with virtual data and quantitative analysis of 3D models, and (2) pathways that may lead to practical improvements for sexing juveniles. The issues associated with sex estimation in juveniles are discussed and approached in the context of a framework that unifies classification results for a given trait, which provide information on its capacity to discriminate between the sexes, with the underlying patterns of dimorphism over ontogeny. Virtual collections of 3D models are suggested as integral to this framework because they enable the magnitude and mode of sexual dimorphism to be comprehensively quantified for a chosen trait or set of traits. Those data can be used to inform decisions about how to apply a method for sex estimation to maximize its success. Virtual collections, through extending the scope of analyses and impacting the way in which questions on sexual dimorphism in juveniles may be answered, are undoubtedly set to play a central role in future research.
PMID: 28689044 [PubMed – as supplied by publisher]
Towards substrate-independent age estimation of blood stains based on dimensionality reduction and k-nearest neighbor classification of absorbance spectroscopic data.
Forensic Sci Int. 2017 Jun 08;278:1-8
Authors: Bergmann T, Heinke F, Labudde D
The age determination of blood traces provides important hints for the chronological assessment of criminal events and their reconstruction. Current methods are often expensive, involve significant experimental complexity and often fail to perform when being applied to aged blood samples taken from different substrates. In this work an absorption spectroscopy-based blood stain age estimation method is presented, which utilizes 400-640nm absorption spectra in computation. Spectral data from 72 differently aged pig blood stains (2h to three weeks) dried on three different substrate surfaces (cotton, polyester and glass) were acquired and the turnover-time correlations were utilized to develop a straightforward age estimation scheme. More precisely, data processing includes data dimensionality reduction, upon which classic k-nearest neighbor classifiers are employed. This strategy shows good agreement between observed and predicted blood stain age (r>0.9) in cross-validation. The presented estimation strategy utilizes spectral data from dissolved blood samples to bypass spectral artifacts which are well known to interfere with other spectral methods such as reflection spectroscopy. Results indicate that age estimations can be drawn from such absorbance spectroscopic data independent from substrate the blood dried on. Since data in this study was acquired under laboratory conditions, future work has to consider perturbing environmental conditions in order to assess real-life applicability.
PMID: 28686961 [PubMed – as supplied by publisher]
Estimation of changes in breech face and firing pin marks over consecutive discharges and its impact on an IBIS(®) Heritage™ System.
Forensic Sci Int. 2017 Jun 29;278:47-51
Authors: Kirk JN, Law EF, Morris KB
When a firearm is discharged, the individual marks of the breech face and firing pin are imprinted onto the primer of the cartridge case. These individual marks are reproducible between shots; however, over a large number of consecutive shots, it has been observed that minute changes in these individual marks may occur. Changes in individual marks may affect an examiner in their ability to identify or eliminate and may change the magnitude of a likelihood ratio, depending on the system used by the laboratory, but the effect that these changes have on the Integrated Ballistic Identification System (IBIS(®)) is largely unknown. If such changes negatively affect the performance of the IBIS(®) then consequences may result with respect to the correct matching candidate not be returned in the top results further compared by an examiner. Two hundred consecutive test fires performed in a clean environment (indoor shooting range) were collected in sequence from 24 new Ruger(®) SR9 9mm pistols and entered into an IBIS(®) Heritage™ System. The full known match data were extracted for each firearm, and δ sets were created that had a specific number of cartridge cases between the two cartridge cases being compared. Receiver operating characteristic (ROC) area under the curve (AUC) values for these δ sets were compared to the full known match sets to determine if any significant changes in performance resulted. Although there were instances of significant differences, these only occurred in less than 25% of comparisons, and overall no decreasing trends in performance were observed.
PMID: 28689045 [PubMed – as supplied by publisher]
Worldwide population variation in pelvic sexual dimorphism: A validation and recalibration of the Klales et al. method.
Forensic Sci Int. 2017 May 08;:
Authors: Kenyhercz MW, Klales AR, Stull KE, McCormick KA, Cole SJ
Sex estimation is an integral aspect of biological anthropology. Correctly estimating sex is the first step to many subsequent analyses, such as estimating living stature or age-at-death. Klales et al. (2012)  provided a revised version of the Phenice (1969)  method that expanded the original three traits (ventral arc, subpubic concavity/contour, and medial aspect of the ischio-pubic ramus) into five character states to capture varying degrees of expression within each trait. The Klales et al. (2012)  method also provided associated probabilities with each sex classification, which is of particular importance in forensic anthropology. However, the external validity of this method must be tested prior to applying the method to different populations from which the method was developed. A total of 1915 innominates from four diverse geographic populations: (1) U.S. Blacks and Whites; (2) South African Blacks and Whites; (3) Thai; and (4) unidentified Hispanic border crossers were scored in accordance with Klales et al. (2012) . Trait scores for each innominate were entered into the equation provided by Klales et al. (2012)  for external validation. Additionally, recalibration equations were calculated with logistic regression for each population and for a pooled global sample. Validation accuracies ranged from 87.5% to 95.6% and recalibration equation accuracies ranged from 89.6% to 98% total correct. Pooling all samples and using Klales’ et al. (2012)  equations achieved an overall validation accuracy of 93.5%. The global recalibration model achieved 95.9% classification accuracy and can be employed in diverse worldwide populations for accurate sex estimation without the need for population specific equations.
PMID: 28666560 [PubMed – as supplied by publisher]
Sexual dimorphism of the calcaneus in contemporary Cretans.
Forensic Sci Int. 2017 Apr 15;:
Authors: Nathena D, Michopoulou E, Kranioti EF
During the past decade, several studies have been carried out using the calcaneus bone for sex estimation. This paper collected data using ten variables for metric characteristics of the calcaneus of 144 modern Cretans and examined their correlation with known sex. Secondly, the formulae developed by Peckmann et al. (2015) for modern Athenians was put to the test in order to investigate if it could be applied to this modern Cretan sample as well. Results showed a high correlation between the calcaneus metrics and the known sex of the individuals, however the formulae for Athenians do not seem to be suitable for the Cretans due to the high sex bias reported in this study. Thus, new standards were created for sex estimation from the calacanei in our sample. Bilateral asymmetry was noted in the majority of cases, thus formulae were developed for left, right and mean values. Maximum width (MAXW) was the variable that performed the best in the Cretan sample. Overall, the cross-validated accuracies for univariate and multivariate equations reached 84.2% with males most often correctly identified. The calcaneus was proved to be useful for sex estimation in this modern Cretan population. Further work will explore the suitability of the produced standards for other regions of mainland Greece and islands.
PMID: 28625510 [PubMed – as supplied by publisher]
First records of Synthesiomyia nudiseta (Diptera: Muscidae) from forensic cases in Italy.
Forensic Sci Int. 2017 May 10;:
Authors: Lo Pinto S, Giordani G, Tuccia F, Ventura F, Vanin S
The knowledge of the fauna associated with carrions and cadavers for a specific region plays a fundamental role in the estimation of the time since death in forensic cases. In the last years global warming and globalization have affected the insect species distribution. This phenomenon is affecting also the species of forensic interest associated with the cadaver decomposition. The species distribution shift, in the forensic context, has been mainly observed in Diptera of different family: Calliphoridae, Stratiomyidae and Phoridae. In the last decade the presence of the carrion feeding species, Synthesiomyia nudiseta (Diptera: Muscidae), was reported from forensic cases in Spain and in the last year from Italy where the species was collected from 5 bodies in different decomposition stages in the Genoa district. All the records concern indoor cases with the presence of other species belonging to the first colonization waves (e.g. Calliphoridae, Sarcophagidae). Different hypothesis about the presence of the species in Italy can be suggested, but the molecular analysis and the importation records support the introduction trough commercial exchanges with Asian countries instead of a variation in the species distribution area from the Iberian Peninsula.
PMID: 28526458 [PubMed – as supplied by publisher]