Journal of forensic sciences最新文献

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.

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.

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.

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.

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.

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.

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.

Recently, an unusual method of home burglary has emerged in several European countries. Nitric acid is used to attack the tumbler lock of the front door. The aim of this study is to gain insights into the technical functioning of this method and to evaluate the advantages and disadvantages of this modus operandi. For this purpose, four pin-tumbler locks were attached to a custom-made holder and 65% nitric acid was successively injected into the key channel using a syringe. The locks were checked manually and using a CT scanner to see whether the lock was overcome and how the acid did affect the pins and springs. In three out of four cases the lock was overcome. The shortest time was 22 min until the pin pairs could be removed and it was possible to turn the core with a screwdriver. Overall, the results show that the modus operandi works with standard locks. According to the authors, the long duration and the high health risk are significant disadvantages in relation to other overcoming methods.