Journal of forensic sciences最新文献

Forensic evidence recovered from crime scenes often contains a mixture of human and bacterial DNA. Although short tandem repeat (STR) profiling of genomic DNA (gDNA) is widely used for human identification, its effectiveness can be limited in cases involving highly degraded DNA. In such cases, human mitochondrial DNA (mtDNA) and microbiome analysis may serve as alternative methods. In this study, we developed a multiplex quantification assay targeting the bacterial 16S rRNA V7 region and the human mitochondrial NADH-dehydrogenase subunit 5 (ND5) gene. Quantification was performed using TaqMan-based real-time PCR (Human-Bacteria qPCR; HBQ) and droplet digital PCR (Human-Bacteria ddPCR; HBD). Optimal primer and probe concentrations were at 7 μM for the HBQ assay, and 5 μM bacterial primer set, 7 μM human mtDNA primer set, and 700 nM probes for the HBD assay. Sensitivity testing showed that the HBQ assay detected all DNA samples-except G147A-down to 20 fg, while the HBD assay detected both bacterial and human DNA at 20 fg, demonstrating higher analytical sensitivity than the real-time PCR method. Moreover, mock forensic samples were analyzed to confirm the assay applicability, and PCR inhibitor tolerance tests using humic acid and tannic acid were conducted to further validate their performance. Furthermore, the HBQ and HBD assays may be used in quality control processes for samples potentially affected by bacterial DNA or human mtDNA contamination and could also be applied to other fields such as food safety, environmental science, and biological research involving microbial DNA and human mtDNA.

Sex estimation methods from the pelvis have been well-studied in research settings to estimate accuracy, error, and bias. However, patterns in casework are minimally described. We uniquely examine forensic anthropology casework in the United States retrospectively for the Phenice and Klales et al.'s sex estimation methods. Our hypothesis is that casework patterns will reflect the greater literature derived from research settings that show Phenice's method is more accurate and has lower error and sex bias. We use the publicly available Forensic Anthropology Database for Assessing Methods Accuracy. A sample of 229 cases from the United States reported the outcomes of applying these methods. McNemar's tests evaluate whether estimated sex is consistent with documented sex, and a Fisher's exact test compared the performance of the two methods. We further calculated accuracy, error, and sex biases of the methods. The McNemar's and Fisher's exact tests were not statistically significant, which indicates that both methods estimated sex at a rate close to the documented sex and to each other. Phenice's method displayed an accuracy of 99.4%, an error of 0.6%, and a sex bias of -2.4%. Alternatively, the Klales et al.'s method performed slightly lower with a 97.5% accuracy, 2.5% error, and 3.5% sex bias. Forensic anthropology casework in the United States reflects broader patterns in accuracy, error, and bias in the research setting literature, where Phenice outperforms the Klales et al.'s method, despite the values from casework probably reflecting practitioners using information beyond the method reported to make a final sex estimate.

The demand for analyzing images from sources such as closed-circuit television cameras has increased significantly. Conventional analyses, including gait and soft biometrics, typically require the comparison of two video footage clips, as these methods are predicated on video-to-video comparisons. Moreover, numerous prerequisites often limit their applicability, particularly in the field of gait biometrics. To address these limitations, this paper introduces a simple yet effective image-to-person comparison method, leveraging image reproduction from a structure from motion (SfM)/photogrammetry-based three-dimensional (3D) computer graphics reference virtual avatar. This avatar is generated from a reference real person. It is demonstrated that the proposed method, by applying 3D joint manipulations to the reference virtual avatar, qualitatively reproduces a person captured in a target image with high fidelity. Furthermore, quantitative silhouette comparisons successfully confirm distributions for forensic image-to-person comparison. The proposed method holds promise as a body shape-based forensic image-to-person comparison tool in scenarios where a real person can be used as a reference.

The rapid advancement of deepfake technology poses a significant threat to digital content authenticity and public trust. Deepfakes leverage artificial intelligence to generate realistic yet manipulated images and videos, often for deceptive purposes. This study introduced an enhanced version of the MesoNet convolutional neural network tailored for deepfake detection. The model incorporates two additional convolutional layers, resulting in substantial performance gains across various metrics. It achieved a precision of 96.60%, recall of 95.33%, F₁-score of 95.96%, accuracy of 95.59%, and a Matthews Correlation Coefficient (MCC) of 91.11%, outperforming baseline models such as ResNet-50, VGG variants, and AlexNet. Additionally, a real-time detection system was developed using a React frontend and Flask backend, demonstrating the model's potential for practical deployment. This research contributed a robust and scalable approach to deepfake detection and lays the groundwork for real-world applications in digital forensics and content authenticity verification.

This case study reports the forensic identification of N-methylaniline (NMA) in an automotive gasoline sample seized from a gas station in Brazil, with a semi-quantitative estimate of ca. 1.9% (v/v), indicating a case of fuel adulteration. Although NMA has been investigated in experimental fuel formulations as a potential nonmetallic anti-knock additive capable of increasing octane rating, to the best available knowledge, no previous studies have reported its detection in real-world gasoline samples. In Brazil, the National Petroleum Agency (ANP) authorizes only previously approved additives, meaning that the presence of NMA constitutes a noncompliant fuel component. The sample was analyzed using gas chromatography-mass spectrometry (GC-MS), tandem mass spectrometry (MS/MS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR). The compound was unambiguously identified and characterized, demonstrating the effectiveness of these complementary analytical techniques for detecting unapproved or unconventional additives in complex hydrocarbon matrices. This case underscores the relevance of forensic fuel analysis for regulatory compliance and highlights the need for continuous monitoring to mitigate health, environmental, and operational risks associated with aromatic amine contamination.

Facial identification examiners assess whether two facial images-such as an image of an unknown person from surveillance footage and a controlled image of a known individual-depict the same person or different people. To communicate their observations, they rely on predefined verbal articulation scales that sometimes have associated numeric equivalents. However, these terms have not been calibrated against the actual strength of the evidence except indirectly through proficiency tests and black box studies. The present research reanalyzes the findings of face comparisons from the most comprehensive facial identification black box study to date, as well as multiple facial examination proficiency tests, to generate a quantitative measure of the strength of the evidence for each comparison. We used an ordered probit model to summarize the distribution of responses of both individual examiners and examiner teams to produce a set of likelihood ratios for each group and test. The likelihood ratios can be lower than values implied by the evaluative statements, which do not seem to justify the strengths of evidence implied by current articulation scales used in facial comparisons. Our analyses suggest that examiners are using language that overstates the strength of the evidence by several orders of magnitude.

Juvenile firesetting remains underexamined in non-Western forensic populations. This study investigated the psychiatric, motivational, and familial characteristics of 55 adolescents (mean age = 15.05 years; 92.7% male) referred for court-ordered forensic psychiatric assessment in Turkey between 2019 and 2025. Structured coding captured motivational subtypes, family adversity, psychiatric diagnoses, co-occurring offending, and incident characteristics. Motivations included antisocial/criminal, anger- or revenge-driven, impulsive, curiosity-related, and distress-linked acts. Family adversity-particularly fragmented caregiving and neglect-was common, alongside high rates of conduct disorder, attention-deficit/hyperactivity disorder, and depression. Fires most frequently occurred at home or outdoors and were typically ignited with lighters. Recurrence occurred in 14.5% of cases and was more strongly associated with delinquent behavior patterns than with psychiatric diagnoses; co-occurring offending independently predicted recurrence (odds ratio = 7.78, p = 0.046). Findings highlight heterogeneous externalizing pathways shaped by cumulative family adversity and extend the international literature by providing forensic evidence from a non-Western context. Results may inform structured assessment and tailored intervention strategies within juvenile justice systems.

Evaluative activity level guidance cautions DNA analysts not to respond to courtroom questions asking "how" and "when" DNA was deposited. However, criminal defendants have the right to confront and cross-examine witnesses against them. Al-Atiyyat v. State is the first U.S. case to address whether a DNA analyst's refusal to answer an activity level question violates a defendant's Sixth Amendment right to confrontation. Under the circumstances described, the court ruled that it does not. This case report examines the Al-Atiyyat decision and provides a detailed description of both the trial and appellate courts' Sixth Amendment analysis, including their collective frustration with the analyst's refusal to respond to defense counsel's activity level question. That frustration is symptomatic of the tension between current scientific guidance on activity level testimony and U.S. legal standards that control such testimony-whether evaluative or informal. This case report compares existing activity level guidance with relevant case law that governs the scope of a DNA analyst's testimony. It concludes that a gap exists between current guidance and U.S. law, which considers DNA analysts both qualified to offer opinions on activity level questions and legally obligated to respond to defense questions on cross-examination. The parties should litigate anticipated activity level issues before trial, so the court can define the proper scope of anticipated questions and testimony. The U.S. forensic DNA community should publish substantive guidance for analysts faced with activity level questions first raised during trial that considers both scientific and relevant legal principles.

Psychopathy is a multidimensional disorder influenced by behavioral, social, and biological factors. Minor physical anomalies (MPAs) are subtle morphological variations that arise from developmental disruptions during the prenatal period and are considered potential phenotypic indicators of such neurodevelopmental irregularities. Previous research has examined several neurodevelopmental aspects of psychopathy. However, the specific relationship between MPAs and psychopathy has not yet been systematically investigated. This cross-sectional study investigated the association between MPAs and psychopathy levels. The sample comprised 114 male offenders meeting DSM-5 criteria for Antisocial Personality Disorder (ASPD) and 54 healthy controls matched for age and sex. Psychopathy was assessed using the Psychopathy Checklist-Revised, and participants were classified as low (LP) or high psychopathy (HP). MPAs were evaluated using the Waldrop Minor Physical Anomaly Scale. Results indicated that total, craniofacial, and peripheral MPA scores were significantly higher in the HP group than in LP and control groups (p < 0.001). Psychopathy level strongly correlated with total MPA score (r = 0.83, p < 0.001). Regression analysis showed that MPAs, particularly craniofacial anomalies, were stronger predictors of psychopathy than psychosocial factors (B = 0.710, p < 0.001). This study demonstrated a significant association between MPAs and the level of psychopathy. The findings suggest that lower levels of psychopathic traits are more closely related to psychosocial factors, whereas higher levels may be more strongly associated with craniofacial MPAs. Multicenter and longitudinal studies examining neurodevelopmental and psychosocial interactions may contribute to a deeper understanding of the developmental dynamics of psychopathy.

Trace DNA can be deposited onto a wide range of surface types which can include substrates with a coating of oil: examples being firearm components, power tools, and kitchen utensils. We report on the impacts of oil on DNA recovery and downstream DNA processing. Thumbprints were made on 60 separate glass slides, then stained with Diamond Dye and fluorescent cellular material counted as an estimation of the cells deposited. Aliquots of five different mineral oils, chosen due to their common uses and variation in viscosity, were spread across the entire deposited thumbprint. The thumbprints coated with one of the five oils were left at room temperature for either 1 day or 7 days. A swab was used to collect cellular material which was then processed manually through a DNA extraction process, quantified and STR alleles amplified using the VeriFiler™ Plus STR kit. It was observed that all five oils impacted the initial DNA recovery process by saturating the swab. The presence of oils also impacted the DNA extraction process by interacting with the magnetic resin. Oils with higher viscosity accentuated these observed effects during the DNA extraction process, as the presence of a white precipitate was seen to be carried over into the final eluate. A total of 56% of the 1-day samples and 72% of the 7-day samples resulted in DNA profiles comprised of 12 or more alleles. The results of this study highlighted the possible impacts of collecting samples with oils present on the surface.