Journal of forensic sciences最新文献

Tape is a type of trace evidence commonly seen in forensic science. Little to no research has been published regarding the optimal storage material for pressure-sensitive adhesive (PSA) tape. The purpose of this project was to determine the substrate with the least amount of interference for storing PSA tape. Interferences such as difficulty removing tape from the substrate or substrate components leaching into the adhesive can affect the analysis. This was a long-term study in which samples were stored on various substrates for nearly 10 years. Ten different tape samples were placed on eight different substrates for a total of 80 samples. The substrates included typical materials currently used for tape storage as well as other, less common materials. The tape samples were evaluated for ease of removal at various time intervals. The adhesives from each tape were analyzed at similar time intervals by Fourier transform infrared spectroscopy (FTIR). In addition, the adhesives were analyzed by pyrolysis gas chromatography–mass spectrometry (PyGC-MS), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and x-ray fluorescence (XRF) at the last time interval (112 months) and compared to the adhesive tape samples from the original rolls of tape to determine if there was any adverse effect from the substrates during storage. The FedEx backing was the only substrate that had no adverse effects regarding ease of removal. The substrates that had the least effect on the adhesive for both short-term and long-term storage included FedEx backings, adhesive sheet backings, and polyester transparency sheets.

Identifying the species of shark responsible for a bite on humans is both complex and important for understanding and managing the shark risk. Depending on the species, tiny teeth may or may not be present in the symphyseal space at the junction of the upper and lower half-jaws. In the case of bites, these tiny teeth (if present) often leave specific marks that may enable species to be quickly and reliably distinguished. We first present the anatomo-morphological characteristics of the jaws of the three most traumatogenic species for humans which are the white, tiger, and bull sharks. The white shark has no symphyseal teeth, while the tiger and bull sharks do. On the basis of three confirmed real case studies involving those species, we then show that for the white shark, the wide symphyseal space between the first two teeth of each jaw usually leads to wounds including the presence of (quite) large flesh flaps, without any tooth imprint. Conversely, wounds following bites made by the tiger and bull sharks will generally leave characteristic small imprints of symphyseal teeth, especially in the case of incomplete or superficial bites. Although not systematic, this diagnostic approach provides fast, reliable, and clean results. The discrimination between two species with symphyseal teeth can then be made on the basis of complementary anatomic information such as jaw curvature and details linked to the anatomy of the teeth themselves, as well as the ecological context.

Despite developing prior to the appearance of secondary sexual characteristics of the skeleton, the permanent dentition exhibits sexual dimorphism. Therefore, teeth can serve as a means to estimate sex assigned at birth even in young individuals. This project takes a large global sample of maximum dimensions of the crown as well as measurements of the crown at the cervix to explore sexual dimorphism. Dimorphism is noted in teeth throughout the dental arcade, particularly in the canines. We provide sectioning points as well as the probability of correct classification (ranging from 50.9% to 81.3%) for each measurement to aid the practitioner in sex estimation from the dentition. This research provides a method to estimate sex without arbitrary population specifications. We argue for a global approach that incorporates more population variation to remove the need to estimate “ancestry,” (which in actuality is translated to a social race category) and therefore does not force sexual dimorphism-related variation into these mutable and ambiguous categories. Further, this paper demonstrates the utility of the dentition as an additional indicator to aid with the estimation of sex assigned at birth in forensic anthropology. The goal of this research is to better understand the expression of sexual dimorphism across the skeleton in a global context.

In this work, we employed a new ambient ionization mass spectrometry technique, sandpaper spray mass spectrometry (SPS-MS), as an efficient tool to analyze pills and tablets of pharmaceutical formulations. The following samples were analyzed: regulators of blood pressure, cholesterol, and diabetes, and drugs for the treatment of erectile dysfunction (ED). Additionally, a hard candy of Cannabis sativa containing Δ9-tetrahydrocannabinol (Δ⁹-THC) and its related isomer cannabidiol (CBD) was also evaluated. The surfaces of the samples, without any prior treatment, were sanded onto triangular-cut sandpaper, and full MS scans (and MS/MS) were acquired in both positive and negative ionization modes. SPS-MS (and MS/MS) allowed for prompt detection of the active pharmaceutical ingredients (APIs) in each formulation. Other components of the formulations, added as excipients, were also tentatively identified. The results described herein indicate that the SPS-MS technique can be applied to fast screening of pills and tablets being potentially used as an efficient tool to detect counterfeit pharmaceutical and illicit products, a current issue of increasing concern.

A comparison of error rates between studies in forensic handwriting examination has been made in response to the lack of knowledge on error in this field. Fifteen indicators have been used to describe and compare error rates between studies. The results of each study have been processed to determine these indicators. Parameters related to the participants, conclusion scale, amount of time allocated to the task, and the task itself are also reported. The error rate indicators are provided for each study, and then combined across studies using values of mean and standard deviation. Experts were found to perform better than laypeople. For handwritten texts, absolute error rate for experts ranges from 0.32% to 5.85% (with a mean of 2.84 ± 2.33%), and for laypeople from 11.43% to 28.72% (with a mean of 21.40 ± 8.94%). For signatures, absolute error rate for experts ranges from 0% to 4.86% (with a mean of 2.50 ± 1.55%), and for laypeople from 10.68% to 28% (with a mean of 19.55 ± 7.05%). Overall, experts have an absolute error rate of 2.63 ± 1.73% (against 20.16 ± 7.20% for laypeople). Experts are also more likely to give inconclusive answers than laypeople. Overall, the rate of absolute inconclusive answers for experts is 21.96 ± 23.15% (against 8.13 ± 7.96% for laypeople). The comparative review of error rates presented in the present article contributes to validating the discipline by showing how research has been devoted to meeting the criteria of testing to be considered scientific.

This study investigated the stroke and slope characteristics in left-handed and right-handed handwriting. Stroke (letters t, f, đ, and H) and slope (letters t, f, l, d, and g) directions were analyzed on in-house samples (n = 64), revealing statistically significant differences (p ≤ 0.05) between the groups. Right-handers predominantly exhibited left-to-right strokes (98%–100%), while left-handers showed greater variability. Although statistically significant for most letters analyzed, slope direction did not demonstrate consistent patterns. A logistic regression model was developed and validated on the same sample to classify handedness based on the averaged strokes of the letter “t.” The model was further tested on samples (n = 252) from a publicly available handwriting database. If the model classified the sample as produced by left hand, it was correct in 100% of cases. In contrast, when the model classified writing as right-handed, it was correct in 73%–97% of cases, depending on the validation sample. The model classified writing as of left-handed origin if more than 36% of the letters “t” had a stroke from right to left, while otherwise, writing was classified as of right-handed origin. The developed method showed great potential for classifying the handedness of the author of disputed handwriting, thus eliminating individuals as text authors or narrowing down the pool of potential authors.

In tool mark identification, there is still a lack of characteristics and methodologies standardization used to analyze and describe sharp force trauma marks on skeletal remains. This study presents a classification method for cut marks on human bones, providing an applicable methodology for their examination and the relevant terminology for describing cases of sharp force trauma. A total of 350 cut marks were produced by stabbing pig ribs (Sus scrofa) with seven knives. The samples were analyzed under a stereomicroscope with a tangential light source. Through the analysis of cut marks, eleven traits were identified as significantly associated with the type of knife used. These traits included the general morphology of the kerf shape, the entrance and exit cross-profile shapes, the location of the rising on the entrance and exit cross-profile, the presence or absence of feathering, the presence or absence of shards and the location and the general morphology of the mounding. Binary logistic regression models were later trained and tested using nine out of the eleven traits. The first model categorized the cut mark as either produced by a serrated or non-serrated blade, while the second, as either produced by a single- or double-beveled blade. Classification scores of those models ranged between 63%–85% for the serration class and 63%–89% for the blade bevel class. This study proposes a new set of traits and the use of machine learning models to standardize and facilitate the analysis of stab wounds.

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by marked differences in communication patterns, reciprocal social interactions, and restricted, stereotyped, and repetitive interests and activities. Various behavioral problems in ASD, more so when accompanied by coexisting psychopathology, can sometimes lead to legal problems. In this study, the cases in which an opinion was requested in terms of criminal responsibility with the diagnosis of ASD in the 5-year period between 2018 and 2022 in the expertise department of psychiatric observation, where psychiatric cases were hospitalized and observed in the Council of Forensic Medicine (CFM), which is the official expert institution in Türkiye, were retrospectively evaluated. The mean age of the group whose criminal responsibility was reduced or removed was 22.9 years (±7.52) and the mean IQ score was 76.63 ± 18.94. The most common crime in this group was intentional injury (5/11), and it is noteworthy that the victims of these crimes were usually relatives of people with ASD (5/6). The criminal acts of people with ASD are usually single-movement, spontaneous, unplanned, impulsive acts. In addition, although there is no problem in cognitive perception in people with high functioning ASD (HF-ASD), various forensic situations may arise due to defects in emotional awareness. When we look at the practices of the CFM in Türkiye, it is seen that in cases where the diagnosis of ASD is clear and can be associated with the crime, criminal responsibility is usually completely eliminated. In HF-ASD types, although it is important to be associated with the crime, it is seen that criminal responsibility is generally reduced.

Estimating biological sex is a crucial aspect of forensic anthropology, and is pivotal in forensic investigations. Presently, the most frequently adopted osteological sex estimation methods focus on the anterior pelvis, which is easily susceptible to postmortem damage, revealing a need for additional accurate methods. This study introduces a novel method for estimating adult sex through metric pelvic scar analysis, using a known skeletal sample (169 females; 51 males). Relationships between sex and scar dimensions were subjected to Kendall's tau-B testing, and the strongest associated measurements were further analyzed using binary logistic regression to determine their predictive capacity. The final estimation method was tested on an additional known-sex sample of 43 males and 43 females from the Spitalfields skeletal collection. All associations between biological sex and scar measurements were significant, with the preauricular sulcus and newly defined inferior interosseous cavity presenting the strongest relationships (τb 0.223–0.504). Individual regression models using the approximate volume of each feature predicted sex with over 80% accuracy, but when combined in a single regression model, the accuracy increased to an impressive 97.1%. When then applied to the validation sample, the final estimation model achieved an accuracy of 90.7%. These results highlight the high estimation accuracy achieved by simultaneously utilizing the approximate volume of the sulcus and the inferior cavity. This is not only highly accurate but also utilizes the sturdier posterior pelvis, making it a promising tool for forensic investigations and the wider field of osteology.

In mass disaster events, forensic DNA laboratories may be called upon to quickly pivot their operations toward identifying bodies and reuniting remains with family members. Ideally, laboratories have considered this possibility in advance and have a plan in place. Compared with traditional short tandem repeat (STR) typing, single nucleotide polymorphisms (SNPs) may be better suited to these disaster victim identification (DVI) scenarios due to their small genomic target size, resulting in an improved success rate in degraded DNA samples. As the landscape of technology has shifted toward DNA sequencing, many forensic laboratories now have benchtop instruments available for massively parallel sequencing (MPS), facilitating this operational pivot from routine forensic STR casework to DVI SNP typing. Herein, we present the commercially available SNP sequencing assays amenable to DVI, we use data simulations to explore the potential for kinship prediction from SNP panels of varying sizes, and we give an example DVI scenario as context for presenting the matrix of considerations: kinship predictive potential, cost, and throughput of current SNP assay options. This information is intended to assist laboratories in choosing a SNP system for disaster preparedness.