Journal of forensic sciences最新文献

In forensic handwriting analysis, it is crucial to understand the relative frequencies of findings relevant to the specific author, especially when using statistical methods. These are factored into the likelihoods used to determine the probabilities for the different authorship hypotheses. However, if ad hoc writings are included in the comparison materials, the representation of a comparison writer's habits can be distorted. An overrepresentation of certain creation time points can be avoided by treating ad hoc series of comparison writing samples as internally homogeneous agglomerates, incorporating only a single value per series into the average relative frequency of a given finding for a comparison writer. Additionally, the proposed approach produces finding counts largely independent of the length of the handwriting sample, which has a positive impact on the efficiency and cost-effectiveness of the expert evaluation.

Deepfake videos are growing progressively more competent because of the rapid advancements in artificial intelligence and deep learning technology. This has led to substantial problems around propaganda, privacy, and security. This research provides an analytically novel method for detecting deepfake videos using temporal discrepancies of the various statistical features of video at the pixel level, followed by a deep learning algorithm. To detect minute aberrations typical of deepfake manipulations, this study focuses on both spatial information inside individual frames and temporal correlations between subsequent frames. This study primarily provides a novel Euclidean distance variation probability score value for directly commenting on the authenticity of a deepfake video. Next, fine-tuning of InceptionResNetV2 with the addition of a dense layer is trained FaceForensics++ for deepfake detection. The proposed fine-tuned model outperforms the existing techniques as its testing accuracy on unseen data outperforms the existing methods. The propsd method achieved an accuracy of 99.80% for FF++ dataset and 97.60% accuracy for CelebDF dataset.

Increasingly, studies compare risk and protective factors for involvement in violent and nonviolent terrorist behaviors. This exploratory study investigates whether this distinction is sufficient, or whether it should be disaggregated further into more granular terrorist roles and behaviors. Using data on 404 referrals to a UK countering violent extremism Prevent hub specializing in mental health and associated needs, we compare violent and nonviolent referrals, and then more specific behaviors (vulnerability, proactive extremism, foreign fighting, and violence planning). Bivariate and multivariate analyses show there is value in disaggregating beyond the binary violence versus nonviolence distinction, as more (and more detailed) relationships emerged when using the disaggregated set of behaviors. While gender did not differentiate violent and nonviolent referrals, women were more likely to be referred for radicalization vulnerability or potential foreign fighting. Extreme right-wing and extreme Islamist referrals were no more or less violent overall, but Islamist referrals were disproportionately referred for both the most and least violent behaviors. Personality and developmental disorders were associated with violence, and disaggregated behaviors provided detailed insight into the drivers of these associations. These exploratory findings, while interesting, likely do not generalize beyond our specific sample. Instead, this study's value lies in demonstrating the utility for both research and, eventually, practice of disaggregating beyond violence and nonviolence. The results demonstrate clear operational implications for threat assessment in the need to include a more refined set of risk factors to aid in assessing risk of more relevant outcomes than terrorist involvement overall.

Active euthanasia is legally permissible in only eight jurisdictions worldwide and may only be administered by qualified personnel following specific selection criteria. Mercy killing refers to the deliberate termination of the life of an individual suffering from a terminal chronic medical condition. Detecting both illegally performed active euthanasia and instances of mercy killing presents challenges for forensic pathologists. The presented case describes a mercy killing involving a 72-year-old woman with multiple chronic conditions who was killed by her grandson via heroin intoxication after administration of the anxiolytic alprazolam. Key findings from the external postmortem examination included a single fresh injection site on the inside of the elbow and a superficial T-shaped cut on the flexor side of the left forearm. Toxicological analyses revealed elevated blood levels of heroin metabolites, including 6-monoacetylmorphine and absence of hydroxyalprazolam, indicating an only short survival time following heroin injection. A cocaine concentration in blood was comparatively low but rather high in hair samples. Elderly individuals with multiple chronic conditions are at increased risk of becoming homicide victims. Comprehensive forensic documentation of injection sites is essential to avoid overlooking deaths caused by injection and to differentiate them from medical measures during resuscitation attempts.

The role of sickle cell trait (SCT) in sudden exertional death is well-recognized in sports and military training. However, it is not yet studied for non-firearm arrest-related death (NF-ARD). With extensive multi-pronged searches, a large database (n = 1389) of NF-ARDs was established. For the years 2006-2021 (inclusive) there were 50 NF-ARDs of Black persons in which postmortem evidence of SCT was found. A control cohort consisted of 414 NF-ARDs of Black persons with no reported SCT. The mean age for SCT cases was 33.1 ± 10.4 years versus 37.0 ± 10.4 years for the control group (p = 0.01). The body-mass index for SCT cases was 28.3 ± 6.6 kg/m² versus 30.7 ± 7.6 kg/m² for the control group (p = 0.03). The prevalence of cardiomegaly was 21% for SCT cases versus 39% in the control cohort (p = 0.008). The postmortem prevalence of SCT in NF-ARDs of Black persons (n = 50, 10.7%) was higher than the prevalence of SCT in the US Black population, which is 7.1% (p = 0.003). In this study of NF-ARDs in Black persons, the prevalence of SCT and the differences between the SCT cases and the control cohort suggest that exertional collapse associated with sickle cell trait may be a contributory factor in NF-ARDs.

Chemical analysis aimed at identifying post-explosion residues is critical for investigating crimes or accidents involving explosives, establishing it as a vital area of forensic chemistry. In general, only trace amounts remain in samples analyzed for this purpose, making the presence of interferents a constant concern. Therefore, understanding the materials used from collection to sample preparation is essential for this type of analysis. This study focuses on organic contaminants in collection and laboratory materials analyzed by gas chromatography/mass spectrometry (GC/MS), complementing a previous study by Mauricio et al. (2020), which addressed inorganic contaminants in materials used for similar purposes in ion chromatography (IC). No prior studies have specifically investigated the potential organic interferences introduced by various materials commonly used in forensic laboratories for sample pre-processing, storage, and evidence collection in this context. Plastic films, bottle caps, disposable gloves, syringes, swabs, disposable cups, plastic tubes, and plastic pipettes were examined. GC/MS analyses revealed that certain materials, particularly syringe plungers, gloves, and plastic films, can interfere with the detection of post-explosion residues from explosive emulsions and ANFO (ammonium nitrate-fuel oil). These findings emphasize the importance of evaluating materials for potential interferences prior to sample collection and processing to minimize contamination risks. This study provides significant insights into how commonly used laboratory materials can impact forensic analysis, thereby enhancing the reliability of post-explosion residue analysis and supporting more accurate forensic investigations.

A 77-year-old professional gold craftsman ingested a white powder used in goldsmithing, mistaking the powder for a health supplement. He detected a strange taste and immediately fell sick, reported the incident to 911, and was taken to the emergency room. He died approximately 8.5 h post-ingestion despite treatment. There were no significant findings in the autopsy, the victim's heart blood sample, gastric contents, and the white powder the victim had taken were submitted to the department of forensic toxicology. Using scanning electron microscopy energy dispersive X-ray analysis, potassium and gold (Au) were detected in the white powder. Ion chromatography analysis detected cyanide. Concentrations of cyanide were 0.5 mg/L in heart blood and 13.3 mg/L in gastric contents. Qualitative and quantitative analyses of Au in the heart blood sample and gastric contents using inductively coupled plasma-optical emission spectrometry detected concentrations of 79.8 mg/L and 2010.1 mg/L, respectively. Au and cyanide synergistically enhance cytotoxicity through inhibition of detoxification and increasing intracellular accumulation. In the present case, the detected blood cyanide concentration was sub or minimally lethal, and the blood Au concentration was high. The cause of the victim's death was the combined toxicity of Au and cyanide.

The Response Time Concealed Information Test can reveal that a person recognizes a relevant item (probe, e.g., a murder weapon) among other, irrelevant items (controls), based on slower responses to the probe compared to the controls. A previous study (Lukács, 2022, JARMAC) analyzed the data of 14 experiments and demonstrated that classification accuracy is increased by increased test length (i.e., increased number of trials included in the analysis). However, that study left the important question open whether prior practice (whose trials are not included in the analysis) influences the classification accuracy of subsequent testing (i.e., subsequent trials included in the analysis). Reanalyzing the same data from the 14 experiments (comprising 2223 individual tests), we show that different sections of the test (each with the same number of trials), such as the first and second half of each examined test, do not differ substantially in their classification accuracy. The main implications for real-life application are that, at least up to about 600 trials, prior practice does not affect subsequent tests' results, and the number of examined relevant items or their order of presentation may be freely chosen without compromising the method's validity.

A critical component of the biological profile involves accurate estimation of the age-at-death of the decedent(s). While bias, inaccuracy, and population specificity have plagued age estimation methods, these issues are minimized by Bayesian statistics. Our primary analysis generated ages of transition from the published Suchey-Brooks pubic symphysis dataset and coupled them with informative priors derived from two modern American forensic samples (Forensic Data Bank [FDB] and Forensic Anthropology Database for Assessing Methods Accuracy [FADAMA]) to test the accuracy of Bayesian analysis against the original method. Exact binomial tests assessed the accuracy of the generated age ranges; realized accuracies and bias are reported for final age ranges at various coverages. In a second analysis, the Bayesian Suchey-Brooks parameters and original, non-Bayesian age ranges were also applied to FADAMA. In the primary analyses, the Bayesian approach improved age estimates over traditional ranges, especially for females. Highest posterior density ranges at 95% provided realized accuracies on a holdout sample between 93% and 96% with extremely low bias for most phases. We provide lookup tables with Bayesian age ranges for various coverages. In the second analysis, realized accuracies were slightly higher in the non-Bayesian approach for both sexes (86%-92% vs. 83%-91%), due to lower precision and likely practitioner bias in aging forensic cases. The popularity of the Suchey-Brooks pubic symphysis aging method in modern forensic casework necessitates the use of the Bayesian approach and we encourage practitioners to utilize the lookup tables for forensic casework in the United States.