Journal of forensic sciences最新文献

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.

Surface-enhanced Raman spectroscopy (SERS) was utilized to measure low-level fentanyl concentrations mixed in common cutting agents, cocaine, 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine, and caffeine. Mixtures were prepared with a fentanyl concentration range of 0–339 μM. Data was initially analyzed by plotting the area of a diagnostic peak (1026 cm⁻¹) against concentration to generate a calibration model. This method was successful with fentanyl/MDMA samples (LOD 0.04 μM) but not for the other mixtures. A chemometric approach was then employed. The data was evaluated using principal component analysis (PCA), partial least squares (PLS1) regression, and linear discriminant analysis (LDA). The LDA model was used to classify samples into one of three designated concentration ranges, low = 0–0.4 mM, medium = 0.4–14 mM, or high >14 mM, with fentanyl concentrations correctly classified with greater than 85% accuracy. This model was then validated using a series of “blind” fentanyl mixtures and these unknown samples were assigned to the correct concentration range with an accuracy >95%. The PLS1 model failed to provide accurate quantitative assignments for the samples but did provide an accurate prediction for the presence or absence of fentanyl. The combination of the two models enabled accurate quantitative assignment of fentanyl in binary mixtures. This work establishes a proof of concept, indicating a larger sample size could generate a more accurate model. It demonstrates that samples, containing variable, low concentrations of fentanyl, can be accurately quantified, using SERS.

Modern techniques can generate highly discriminatory DNA profiles from minuscule biological samples, providing valuable information in criminal investigations and court proceedings. However, trace and touch DNA samples, due to their nature, often have lower success rates than other biological materials, such as blood. Further, forensically aware criminals can utilize gloves and meticulously clean the crime scene to remove DNA traces of themselves from contacted surfaces. Air sampling offers a novel approach to the collection of human DNA that has the potential to bypass some of these issues. This study reports on the results of research into the prevalence and persistence of human DNA in the air. The ability to collect human DNA from the air was investigated with the use of an AirPrep Cub Sampler ACD220 in different spaces, with and without the presence of individuals for various durations of sample collection. Results of this study demonstrate that level of occupation and sampling duration each have an influence on quantity and quality of DNA recovered from the air whereas the effects of orientation and distance of participants from the collection device as well as sequence of occupation remain unclear and require further investigation.

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.

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.

During maceration, a string of beads was found near the surgically modified right os coxa and femur of the remains of a 55-year-old woman donated to the Forensic Investigation Research Station at Colorado Mesa University. The remains were initially used in the study of decomposition of human remains, and then macerated to clean the skeleton. Documentation on this decedent noted three separate “hip replacement” surgeries, but no other details. The surgical modifications include significant alterations to the right os coxa and femur consistent with a Girdlestone procedure, generally used to treat an infected hip replacement unresponsive to other treatment. In this procedure, the surgeon removes the femoral head, and in this case, also the portion of the replacement in the os coxa. In this individual, a portion of the proximal femur was reflected, possibly to reduce contact with the os coxa. The beads are consistent with antibiotic beads, used to treat the infection that likely necessitated the Girdlestone procedure. Both the operation and the inclusion of the antibiotic beads are unusual and are potentially useful in the identification process.

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.

In British Columbia, Canada, unidentified skeletal human remains are often recovered by law enforcement or civilians and there is a question if they are modern and of medicolegal significance, or historical or archaeological. We used relatively fast and inexpensive carbon and nitrogen stable isotope analysis of human bone collagen from a selection of these remains (n = 48) combined with a logistic regression model to classify remains as modern, historical, or archaeological. We then confirmed our temporal classification through directly radiocarbon dating each individual and found that we could predict the temporal group with 93% accuracy. In regions where archaeological remains have dietary isotope values distinct from living people, dietary stable isotope analysis can provide a time-, and resource-efficient method to screen cases of unidentified human remains early in death investigation.

Law enforcement officers should now expect to encounter forms of digital evidence at most of their inquiries, and as a result ensure they are prepared to effectively deal with it. This should involve the production of a digital evidence strategy (DES) which describes those actions required of any investigative team to effectively identify, collect, examine, and evaluate any digital devices/data, while also defining the circumstances for when it is appropriate to conduct such tasks. To help officers to produce robust DESs this work provides a DES template which utilizes the “GAMEPLANS” acrostic to identify nine fundamental components that are required of all DESs—“G”–Grounds for investigation; “A”–Authorization; “M”–Method of investigation; “E”–Evaluation of the meaning of any findings; “P”–Proportionality; “L”–Logic; “A”–Agreement; “N”–Necessity; “S”–Scrutiny. Each of these components are described including the sub-tasks that are contained within each, which any officer constructing a robust and effective DES must address (and provide evidence of having addressed). To support this, a DES template file is also provided, which can be utilized by officers.