Journal of forensic sciences最新文献

Obtaining an accepted minimum amount of extracted and purified DNA is critical for generating complete forensic short tandem repeat (STR) profiles. Certain sample types encountered in forensic laboratories may pose challenges in obtaining the desired target amount of extracted DNA, which can be compounded when an extraction yields low recovery, resulting in a loss of the genetic material necessary for downstream forensic DNA typing. While multiple studies have evaluated the impact of extraction chemistries on yield, they often focus on "end-to-end" profiling success rather than quantifying the discrete loss of DNA during the extraction step. This study presents a quantitative framework using digital PCR (dPCR) to benchmark extraction efficiency by comparing known amounts of DNA pre- and post-extraction. Extraction efficiency was evaluated using silica spin column and magnetic resin-based protocols across five input amounts, with three sample types: whole blood, human cells, and pre-extracted DNA. Results demonstrate significant differences in efficiency between protocols for cellular samples, with both methods exhibiting increased variability at the 1 ng threshold. This data also revealed that previously extracted DNA (SRM 2372a) fails to accurately represent cellular extraction dynamics, serving instead as a control for purification-related loss (e.g., column retention) rather than lysis efficiency.

Understanding the dynamics of DNA methylation (DNAm) post-mortem could support forensic applications, particularly the estimation of the post-mortem interval (PMI), age, and sex of remains. In this study, we investigated DNAm changes in pig carcasses (Sus scrofa) as analogs for human decomposition, while measuring the progression of decay. Genome-wide methylation arrays and ELISA assays were run on pig soft tissues collected post-mortem, alongside assessments of DNA integrity. Overall, DNA integrity and DNAm levels declined throughout the post-mortem period, with distinct seasonal differences. We established thresholds for estimating age and sex, referred to as epigenomic profiling, showing that key epigenetic markers retain predictive value post-mortem. Additionally, CpG sites that mapped to the Sus scrofa genome were selected to develop an ElasticNet model that integrated DNAm to estimate the PMI, highlighting the potential of DNAm as an investigative tool. In conclusion, this study is the first to demonstrate the utility of DNAm and epigenomic profiling in extended PMIs, and the first successful attempt to estimate both age and sex post-mortem from DNAm alone.

Barium is an alkaline earth metal widely used in various industrial applications and as a rodenticide. Barium poisoning primarily occurs through occupational exposure or deliberate ingestion. Water-soluble barium compounds, such as barium chloride and barium carbonate, can induce severe neurological, cardiovascular, and muscular toxicity. While atomic absorption spectrometry (AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES), and inductively coupled plasma-mass spectrometry (ICP-MS) are commonly used for barium analysis, this study developed and validated an ion chromatography (IC)-based method utilizing a 250 μL sample loop for the quantitative analysis of barium in blood and qualitative analysis of forensic evidence. The method was validated with a limit of detection (LOD) of 0.03 mg/L and a limit of quantification (LOQ) of 0.10 mg/L. Intra-day and inter-day precision (RSD) ranged from 1.9% to 5.3% and 1.8% to 5.1%, respectively. Intra-day and inter-day accuracy (bias) ranged from 92.1% to 98.9% and 93.2% to 97.1%, respectively, with a linearity of R² > 0.99. The method was successfully applied to a suicide case involving barium ingestion, where barium was detected at 1.66 mg/L in the heart blood, as well as in the gastric contents and crime scene evidence. This IC-based approach provides a reliable alternative for barium determination in forensic toxicology.

Keyword-based search is widely used in digital forensic investigations, yet its effectiveness depends strongly on investigator experience, leading to inconsistent results and missed evidence. While previous studies have explored machine learning and large language models (LLMs) to address this, practical deployment is often constrained by confidentiality requirements and the infrastructure costs of maintaining high-performance models locally. We propose a practical LLM-based keyword augmentation method that expands investigator-supplied seed keywords, whether single words or multiple words, while restricting inputs to non-sensitive case context. This enables rapid evidence triage using file names without transmitting primary evidence content to external services. We validate the approach in three stages: (i) using 426 documents, we confirm that file names correlate with document bodies through semantic similarity and keyword coverage analyses, showing clear separation from randomized file name-content pairings; (ii) in a benchmark of 1500 file names comprising 500 relevant cases and 1000 controls, prompt-only keyword generation using ChatGPT models demonstrates effective retrieval performance, with ChatGPT-4.1 achieving the best overall balance; and (iii) in a usability study involving 20 digital forensic investigators, augmented keywords improve evidence detection, with junior investigators showing statistically significant gains as assessed by the Wilcoxon signed-rank test. Overall, the method supports efficient triage in geographically distributed and large-scale investigations by applying LLM-augmented keywords, thereby reducing experience-related performance gaps.

Glock Inc. introduced the Glock Marksman Barrels (GMBs) for their fifth-generation production model, in which they incorporated an additional rail component to their existing polygonal rifling process. This addition has resulted in debate among firearm examiners regarding its effectiveness for identifications. This study answers important questions regarding their manufacture, the presence of subclass, how the resulting striations differ barrel to barrel, and if the addition of the rail component offers a benefit or hindrance for examiners during microscopic comparisons. Production and manufacturing information was ascertained via a trip to the Glock factory in Smyrna, GA. Glock engineers provided key information on mandrel fabrication and barrel rifling manufacture. Microscopic evaluation of casts obtained from unfired, consecutively manufactured GMBs revealed repeating patterns among sections of each rail. This is a result of mandrel manufacturing practices resulting in subclass carryover during hammer forging. The tool marked surfaces of GMB bullets, 12 fired from each of 10 consecutively manufactured barrels, were scanned into the EvoFinder® system. An objective evaluation utilized the system's algorithm to determine if each fired bullet could be properly assigned to its original barrel, regardless of the region used. Results demonstrate that inclusion of N-max as a criterion for comparison, in the form of a total score calculation, allowed for complete separation of KM and KNM distributions for additional regions. Furthermore, examiners tested with sets prepared from the same bullets, where the LEAs and GEAs were concealed, found no indication that subclass carryover on the rails would result in false positives.

The rapid proliferation of smart devices introduced challenges and opportunities in digital forensics. These devices continuously collect sensitive user data, such as health metrics, location history, and authentication credentials, often stored across complex, platform-dependent environments. This article proposes the digital forensic investigation framework for wearable devices (DFIF-WD), supported by two key algorithms, DFX-WD, and DFA-WD, that enable efficient application-level artifact extraction from smart wearables. The framework emphasizes logical extraction techniques that eliminate the need for administrative privileges, thereby ensuring minimal invasiveness and broader device compatibility. The study successfully identifies persistent digital artifacts from rooted mobile devices through systematically analyzing companion mobile applications associated with commercial smartwatches. The findings reveal significant shortcomings in current data deletion mechanisms and underscore the forensic potential of residual application data. The proposed framework is validated across multiple device ecosystems, highlighting its adaptability, scalability, and relevance in real-world Internet of things (IoT) investigations. This research enhances the reliability and reproducibility of wearable forensics and sets the stage for standardized practices in the evolving domain of IoT digital investigations.

Acute traumatic spinal cord injury (TSCI) is a life-altering yet largely preventable neurological disorder with high morbidity and mortality. Clinical registries typically gather comprehensive trauma data from living patients but often exclude autopsy data from scene-of-injury fatalities, leaving the pathology of acute TSCI underexplored. To address this gap, we reviewed autopsy records from the New York City Office of the Chief Medical Examiner spanning a 15-year period (2003-2018) to characterize the demographic, forensic, and neuropathological features of lethal acute blunt TSCI. Cases were excluded if post-injury survival occurred beyond the acute phase, if there was pre-existing spinal disease or if there was a non-blunt trauma mechanism of injury. A total of 220 cases met inclusion criteria, with a mean age of 48.37 years (range 2-96). Most spinal injuries were accidental and resulted from motor vehicle collisions, falls from standing height, or descents from height. Ethanol was present in approximately one-third of cases. Atlanto-axial dislocation occurred in 14.5% of cases, predominantly among younger individuals who were involved in motor vehicle collisions. Lethal spinal injuries were most commonly single-level fractures. Neuropathological data were available for 184 cases, of which 147 (80%) had concomitant acute spinal cord injury, with cord transections, contusions, and parenchymal softening being the most frequent. Extra-axial hemorrhages involving the epidural and subdural spaces were the most common spinal hemorrhages related to blunt trauma.

Femicides and family-related homicides represent a significant concern, with over 50% of homicides occurring within the family setting. This study aimed to explore the complex factors, including psychological aspects, behind such crimes, focusing on a sample of inmates incarcerated for homicide, attempted homicide, or femicide. The study analyzed data from 11 inmates (8 males, 3 females) incarcerated for homicide or attempted homicide. Demographic, clinical, and criminological data were collected, and psychological functioning was assessed using the Brief Psychiatric Rating Scale (BPRS) and the Symptom Checklist-90-Revised (SCL-90-R). The sample had an average age of 48 years and generally low educational attainment. Significant mental health issues were identified, with 45.5% of participants reporting a history of substance dependence and suicide attempts. Psychological assessments revealed a predominance of anxiety and depressive symptoms, particularly within the domain of negative affectivity. Findings suggest a link between emotional and relational dysfunction and violent behavior, indicating the need for targeted psychological interventions. However, given the small sample size, these results should be interpreted with caution and considered preliminary. Future research should employ more advanced statistical methods and include victims' perspectives to better identify risk factors and improve prevention strategies.

Gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) remains the primary analytical technique used for cannabis analysis in seized drug laboratories. Electron ionization (EI) mass spectra exhibit extensive fragmentation, enabling the identification of cannabinoids by comparison with reference EI mass spectral libraries. However, limitations such as thermal degradation and potential cannabinoid conversion can occur due to the elevated temperatures of the GC inlet. In contrast, liquid chromatography-mass spectrometry (LC-MS) uses a soft ionization technique, such as electrospray ionization (ESI), which predominantly yields the protonated molecule with minimal fragmentation. Even with collisional activation using tandem mass spectrometry (MS/MS) analysis, the product ion spectra are nearly identical for cannabinoid isomers, reducing the effectiveness of this technique for cannabinoid identification. In this study, copper (Cu) salts are used to induce cannabinoid molecular ion formation under ESI conditions, enabling cannabinoid isomer differentiation. Thirteen cannabinoids were analyzed in the presence of Cu, and the resulting MS/MS product ion spectra exhibited fragmentation analogous to cannabinoid EI mass spectra. To evaluate forensic applicability, the EI-like product ion spectra were searched against the NIST 20 EI-MS mass spectral library using NIST MS Search software. Spectral matches confirmed that this alternative approach can generate EI-like data under ESI-MS/MS conditions, improving cannabinoid isomer identification. Additionally, this method was applied to methanolic extracts of authentic cannabis plant material to ensure cannabinoid molecular ion formation in real-world samples. The developed method offers an alternative approach to traditional workflows, while providing spectral data consistent with those routinely interpreted by seized drug analysts.

Electrocution is a significant, preventable cause of medicolegal death. This study conducted a 5-year (2015-2019) retrospective autopsy-based analysis of 386 electrocution fatalities in Türkiye, evaluating demographic, environmental, and forensic findings to identify key epidemiological patterns and safety gaps. Victims were predominantly male (91.45%), with a peak incidence among young adults aged 20-29 (25.9%). Fatalities occurred most frequently during the summer (44.56%) and within workplace settings (53.89%). Notably, low-voltage (<1000 V) alternating current was the primary source of fatalities, accounting for 47.41% of cases. External electrical lesions were most prevalent on the upper extremities, with the left upper extremity identified as the most frequent site (28.2%). In cases where macroscopically distinct burns were absent, histopathological evaluation of skin specimens provided diagnostic confirmation. The most reliable microscopic markers included spindle-shaped nuclei (38.3%), thermoelectric effects (35.3%), and homogenization of dermal collagen (32.7%). Toxicological screening was largely negative for alcohol (83.94%) and illicit drugs (89.12%). Environmental analysis demonstrated that electrical leakage was approximately 2.7 times more likely on wet floor surfaces compared to dry ones. These findings highlight that electrocution fatalities in Türkiye are primarily occupational and accidental, emphasizing the urgent need for widespread adoption of residual current devices and stricter enforcement of workplace safety protocols.