A Robust Approach to Automatically Locating Grooves in 3D Bullet Land Scans

Land engraved areas (LEAs) provide evidence to address the same source–different source problem in forensic firearms examination. Collecting 3D images of bullet LEAs requires capturing portions of the neighboring groove engraved areas (GEAs). Analyzing LEA and GEA data separately is imperative to accuracy in automated comparison methods such as the one developed by Hare et al. (Ann Appl Stat 2017;11, 2332). Existing standard statistical modeling techniques often fail to adequately separate LEA and GEA data due to the atypical structure of 3D bullet data. We developed a method for automated removal of GEA data based on robust locally weighted regression (LOESS). This automated method was tested on high-resolution 3D scans of LEAs from two bullet test sets with a total of 622 LEA scans. Our robust LOESS method outperforms a previously proposed “rollapply” method. We conclude that our method is a major improvement upon rollapply, but that further validation needs to be conducted before the method can be applied in a fully automated fashion.     

Developmental Validation of the ANDE 6C System for Rapid DNA Analysis of Forensic Casework and DVI Samples

A developmental validation was performed to demonstrate reliability, reproducibility, and robustness of the ANDE Rapid DNA Identification System for processing of crime scene and disaster victim identification (DVI) samples. A total of 1705 samples were evaluated, including blood, oral epithelial samples from drinking containers, samples on FTA and untreated paper, semen, bone, and soft tissues. This study was conducted to address the FBI’s Quality Assurance Standards on developmental validation and to accumulate data from a sufficient number of unique donors and sample types to meet NDIS submission requirements for acceptance of the ANDE Expert System for casework use. To date, no Expert System has been approved for such samples, but the results of this study demonstrated that the automated Expert System performs similarly to conventional laboratory data analysis. Furthermore, Rapid DNA analysis demonstrated accuracy, precision, resolution, concordance, and reproducibility that were comparable to conventional processing along with appropriate species specificity, limit of detection, performance in the presence of inhibitors. No lane-to-lane or run-to-run contamination was observed, and the system correctly identified the presence of mixtures. Taken together, the ANDE instrument, I-Chip consumable, FlexPlex chemistry (a 27-locus STR assay compatible with all widely used global loci, including the CODIS core 20 loci), and automated Expert System successfully processed and interpreted more than 1200 unique samples with over 99.99% concordant CODIS alleles. This extensive developmental validation data provides support for broad use of the system by agencies and accredited forensic laboratories in single-source suspect-evidence comparisons, local database searches, and DVI.     

Electrical Pulse Generated Upon Discharging a Firearm and Its Implication for Gunshot Residue Analysis

Ammunition primers consisting of a mixture of lead styphnate, barium nitrate, and antimony (III) sulfide, upon deflagration, lead to the formation of inorganic gunshot residue (GSR). The cations, from their predeflagration form, undergo reduction reactions during burning to form the classic spheroidal, micron-sized particles indicative of GSR. However, the rapidly changing pressure and temperature of the reaction zone implies that the reactions cannot go to completion. In this study, we use a conductivity detector to show that GSR produces an electrical pulse which corroborates the incomplete redox chemistry. We find that the shape of some GSR formed in an electric field also suggests its nonneutral character. Tantalizingly, the formation of GSR might be a result of Coulombic repulsion shattering the molten droplets in to smaller spheroids. Lastly, we suggest that deposition or transfer of GSR could be influenced by static electricity, an area which should be further studied.     

Intentional Homicide: A Fifteen-Year Study (2000–2014) at the Department of Forensic Medicine,University of Rome “Sapienza”

This study analyzes postmortem records from 260 homicide cases autopsied by the Department of Forensic Medicine in Rome from 2000 to 2014. The victims were mainly males (74%) and young (61% aged from 21 to 50 years). Although the victims were mostly Italians, the number of foreign victims (33%) has increased since 1990, primarily due to immigration. The offenders frequently used firearms (39%), particularly in multiple murders. An increase in blunt (20%) and sharp force (32%) weapons was also seen. The primary crime scene was residential (42%), and the head was the most frequently injured body region. Male victims occurred frequently in the context of organized crime (7.6%). In family or intimate-sexual relationships, women were the majority of victims (8%). Forensic pathologists play an important role during investigation. They should consider all the information available to them, including autopsy information, crime scene information, and crime investigation data.     

The Utility of Expanded Conclusion Scales During Latent Print Examinations

During fingerprint comparisons, a latent print examiner visually compares two impressions to determine whether or not they originated from the same source. They consider the amount of perceived detail in agreement or disagreement and accumulate evidence toward same source and different sources propositions. This evidence is then mapped to one of three conclusions: Identification, Inconclusive, or Exclusion. A limitation of this 3-conclusion scale is it can lose information when translating the conclusion from the internal strength-of-evidence value to one of only three possible conclusions. An alternative scale with two additional values, support for different sources and support for common sources, has been proposed by the Friction Ridge Subcommittee of OSAC. The expanded scale could lead to more investigative leads but could produce complex trade-offs in both correct and erroneous identifications. The aim of the present study was to determine the consequences of a shift to expanded conclusion scales in latent print comparisons. Latent print examiners each completed 60 comparisons using one of the two scales, and the resulting data were modeled using signal detection theory to measure whether the expanded scale changed the threshold for an “Identification” conclusion. When using the expanded scale, examiners became more risk-averse when making “Identification” decisions and tended to transition both the weaker Identification and stronger Inconclusive responses to the “Support for Common Source” statement. The results demonstrate the utility of an expanded conclusion scale and also provide guidance for the adoption of these or similar scales.     

An Evaluation of Differentially Spliced Genes as Markers of Sex for Forensic Entomology,,

Blow flies (Calliphoridae) are important medically and economically and are commonly used in forensics as temporal markers in death investigations. While phenotypic traits in adult flies can be sexually dimorphic, sex identification in immatures is difficult. Consequently, little is known about how sex may result in developmental disparities among sexes even though there are indications that they may be important in some instances. Since genetic mechanisms for sex are well studied in model flies and species of agricultural and medical importance, we exploit the sex-specifically spliced genes transformer (tra) and doublesex (dsx) in the sex determination pathway to optimize a sex identification assay for immatures. Using known primer sets for tra and with a novel one for dsx, we develop PCR assays for identifying sex in four forensically relevant Calliphoridae species: Lucilia sericata (Meigen), Lucilia cuprina (Wiedemann), Cochliomyia macellaria (Fabricius), and Chrysomya rufifacies (Macquart) and evaluated their performance. Band detection rates were found to range from 71 to 100%, call rates ranged from 90 to 100%, and no error was found when bands could be called. Such information is informative for purposes of testimony and in preparation for development studies. The developed assays will assist in further differentiating sexually dimorphic differences in development of the Calliphoridae and aid in more accurately estimating insect age when age predictive markers (size, development time, molecular expression) are sexually dimorphic.     

Evaluation of direct PCR for routine DNA profiling of non-decomposed deceased individuals

Forensic DNA profiling is a standard method used in the attempt to identify deceased individuals. In routine investigations, and if available, the preferred sample type is usually blood. However, this requires the invasive re-opening of the body, days or weeks after the autopsy, which is undesirable in resource-constrained mortuary settings. Motivated by the ease of sampling as well as reduced health and safety risks, this study aimed to establish the success rate of generating a full DNA profile on first attempt from buccal swab lysates using a direct PCR approach. Buccal swab samples were collected from 100 unidentified deceased males, and were subjected to direct DNA profiling with use of the Promega PowerPlex® Y23 Kit. At the time of sample collection, these individuals had been stored for between 1 and 887 days. This study shows that full DNA profiles were initially obtained from 73% of samples, which constitutes the first empirical data pertaining to first time success rates of direct PCR from post-mortem buccal lysates. Further investigation of partial and failed DNA profiles using real-time PCR showed that samples did not contain PCR inhibitors, DNA was not degraded, but DNA concentration was particularly low. Repeating DNA profiling with increased lysate input and extra PCR cycles yielded an additional six full DNA profiles, resulting in an overall success rate of 79%. Overall, DNA profile success rate was not associated with the duration of storage (p = 0.387). Lastly, massively parallel sequencing with the ForenSeq™ Signature DNA Prep kit provided more informative profiles for three additional samples. These results indicate that blood should therefore remain the sample of choice in a post-mortem setting, yet buccal lysates hold potential to be optimised further, which may ease the human identification workflow.     

A Review of Proposed Positive Dental Identifications from the World War II Era

In 1949, the American Graves Registration Service Pacific Zone proposed the identification of 27 sets of remains (skulls/crania/mandibles) based on comparisons with written dental records. All were denied, and the remains were buried as unknowns. In 2003 and 2015, the remains were exhumed by the DPAA. Currently, 26 individuals previously recommended for identification have been positively identified. The DPAA Science Director's opinion corresponded with 24 of their recommendations, while DNA excluded three. Caution should be taken by the forensic scientist when building assemblages through skeletal and dental articulation. The forensic odontologist must always consider variations in restorative care/extraction patterns and the possibility of documentation errors when reviewing/interpreting historical and current day dental records used for AM/PM comparisons. The odontologist should base their opinion on the strength of the antemortem/postmortem comparison, number and type of concordances, and distinct dental care and extraction patterns.     

Analysis of Frontal Sinuses for Personal Identification in a Chinese Sample Using a New Code Number

The study of frontal sinuses for personal identification is a considered approach in the forensic field. In Yoshino's system, the frontal sinus patterns of a given person were formulated as a code number (codY) obtained by arranging the class numbers in each classification item. The aim of this work was to use a new code number (codC) with eight digits that includes other two continuous variables obtained as ratios SOR₁ (left frontal sinus area/left orbit area) and SOR₂ (right frontal sinus area/right orbit area), comparing the results with that of Yoshino. Digital radiographic images of the skulls of 150 Chinese people were analyzed. Spearman's partial correlation coefficients were evaluated between variables characterizing frontal sinus patterns. We used a maximum-weight dependence tree for statistical analysis. Results demonstrated that codC significantly reduced the probability of having the same personal code number compared with codY. Our scientific approach results valid for personal identification purposes.     

超龄人员用工法律关系研究 —— 以《审理劳动争议案件解释（三）》第七条为切入点

因《劳动合同法》与《劳动合同法实施条例》存在相左规定,司法实践中,对超龄用工关系性质的认定不统一。《最高人民法院关于审理劳动争议案件适用法律若干问题的解释(三)》第七条对此冲突进行了补正。然而,因超龄用工关系认定理论的不足,仍未能解决司法实务中判断基准与裁判标准不统一问题,影响了司法的稳定性和可预见性。对此问题应以广阔的视角和务实的精神加以检讨:即以"社会保险待遇说"和"特殊劳动关系说"为理论支撑,在辨识劳动关系和劳动法律关系的前提下,从"分类以视之"的分析方式和解决思路入手,厘清超龄用工关系之情形,以准确认定其法律性质。