Journal of forensic sciences最新文献

The increasing use and misuse of gabapentin pose a major risk to public health and traffic safety. Gabapentin has been approved by the Food and Drug Administration (FDA) since 1993 for adjunctive therapy in the treatment of epilepsy and neuralgia but is increasingly being prescribed for numerous off-label uses including insomnia, anxiety, depression, and migraine. Reported side effects include blurred vision, drowsiness, and loss of coordination. Driving behaviors such as exiting the lane of travel and crashes have been reported in connection to drugged driving investigations concerning gabapentin. To further assist with the toxicological interpretation of gabapentin in driving under the influence of drugs (DUID) scenarios, a review of approximately 108,000 gabapentin-positive DUID cases was conducted. Of those, 858 cases met inclusion criteria and underwent additional evaluation. Blood specimens were screened via enzyme-linked immunosorbent assay (ELISA) and confirmed by liquid chromatography tandem mass spectrometry (LC–MS/MS) for quantitation of gabapentin. This review found an overall DUID gabapentin positivity of 7.9% between January 2020 and December 2022; 17 states from various geographical regions had at least one positive gabapentin DUID case. Observations in six driving and human performance cases where gabapentin was the only drug reported were consistent with the known adverse effects of the medication. Half of the case histories reviewed involved crashes where the driver was determined to be at fault. Additionally, 94% of the cases in this review involved gabapentin in combination with other drugs. The most prevalent drug combinations were opioids and gabapentin present in 64% of cases.

Manual ground searches and cadaver dogs are traditional methods for locating remains, but they can be time- and resource-intensive, resulting in the decomposition of bodies and delay in victim identification. Therefore, thermal imaging has been proposed as a potentially useful tool for detecting remains based on their temperature. This study investigated the potential of a novel search technique of thermal drones to detect surface remains through the detection of maggot mass temperatures. Two trials were carried out at Selangor, Malaysia, each utilizing 12 healthy male Oryctolagus cuniculus European white rabbits and DJI Matrice 300 RTK drone China, equipped with a thermal camera; Zenmuse H20T to record the thermal imaging footage of the carcasses at various heights (15, 30, 60–100 m) for 14 days for each trial. Our results demonstrated that the larval masses and corresponding heat emissions were at their largest during the active decay stage; therefore, all the carcasses were observable in thermal images on day 5 and remained until day 7. Statistical analyses showed that (1) no statistically significant differences in thermal images between clothed and unclothed subjects (p > 0.05); (2) 15 m above ground level was proven to be the optimal height, as it showed the greatest contrast between the carcass heat signature and the background (p < 0.005). Our data suggested the potential window of detection of thermal signatures was detectable up to 7 days post-deposition. This could be an important guideline for the search and recovery teams for operational implementation in this tropical region.

Refractive errors (RE) are commonly reported visual impairment problems worldwide. Previous clinical studies demonstrated age-related changes in human eyes. We hypothesized that the binocular RE metrics including sphere and cylinder power, axis orientation, and interpupillary distance (IPD) can be used for forensic age estimation of an unknown individual. RE data of both eyes were collected from the clinical optometric exams and prescription glasses of 2027 Egyptian individuals aged between 2 to 93 years. The differences between age groups as well as sides, and sexual dimorphism were explored. Two modeling methods were compared: multiple and stepwise linear regression (LR) versus machine learning Regression Forest (RFM). Data were apportioned into training and test datasets with a ratio of 80/20. The results showed significant differences among the age groups in each eye for all variables. Stepwise LR improved the results over models based on the one-sided lens due to selection of IPD in addition to the left and right axis, and left sphere as independent variables. For the RFM, the left axis and IPD were the most important features. RFM outperformed LR in terms of accuracy and root mean squared error (RMSE). The estimated age within ±10 years showed 81.4% accuracy rate and RMSE = 8.9 years versus 38.5% accuracy rate and RMSE = 17.99 years using RFM and stepwise LR, respectively, in the test set. The current study upholds the significance of the age-related changes of refractive error in formulating alternative forensic age estimation models when standard methods are unavailable.

Plastic bags, such as ziplock bags, have been used to transport illicit materials worldwide; however, very few studies have tried to optimize the recovery of DNA from these items. This study reports on the best combination of swabs and moistening solution for the greatest recovery of cellular material from ziplock bags. Five swabs, two different variations of Copan Diagnostics nylon 4N6FLOQSwabs, one Medical Wire rayon DRYSWAB, one IsoHelix rayon swab, and one Livingstone cotton swab, were evaluated with two moistening solutions, Triton X-100 in either distilled water or isopropanol. Fingermarks were deposited on ziplock bags and stained with Diamond™ Nucleic Acid Dye to allow visualization of the cells pre- and post-swabbing to determine the number of cells recovered. Based on cell counting data, swabs moistened with Triton X-100 in distilled water performed better than those moistened with isopropanol. Livingstone cotton swabs had the worst recovery of cellular material, while the other swabs tested had no significant difference in their respective solutions. A comparison of the best three swabs for cellular recovery yielded no differences in the DNA concentration extracted. A linear relationship was observed between the log number of cells recovered by swabbing and the DNA concentration following extraction and quantification. The process of monitoring cell collection using fluorescence microscopy on ziplock bags allowed evaluation of swabbing efficacy. Additionally, this study highlights the ability to evaluate cellular recovery independently of traditional extraction, quantification, or profiling techniques which may unequally affect samples.

Artifacts produced by postmortem animal scavenging are commonly encountered at autopsy. Knowledge of the pattern of artifacts produced by postmortem animal scavenging is essential for the correct interpretation of the autopsy finding. In household deaths, such artifacts are usually caused by domestic animals and by small insects such as flies, ants, beetles, etc. Ants are one of the early scavengers which feed on the dead bodies. The artifacts produced by the postmortem ant activity are usually superficial and non-bleeding type. Rarely, in the congested body regions and areas of marked hypostasis, postmortem bleeding artifacts due to ant bites are possible. In the reported case of hanging, such postmortem bleeding artifacts were present over both the legs, predominantly over the left leg. Typical ant bite lesions in the form of superficial excoriations were also present over the peri-ligature area, over and around both nipples and over the lower part of the abdomen. Morphologically, postmortem bleeding artifacts produced by ant bites exhibit four patterns: droplet pattern, stripe pattern, pool pattern, and mixed pattern. In this case, a mixed pattern (droplet pattern and stripe pattern) of postmortem bleeding artifacts was observed. The presence of postmortem bleeding artifacts over the lower limbs was attributed to the pooling of the blood due to suspension of the body, followed by passive escape of blood due to ant bites. The possibility of such artifacts produced by ant bites should be considered when the origin of the lesion is unclear.

Determining specific line-crossing sequences has always posed a challenge for document examiners. Interactions between pen ink and stamp seal ink can be complicated and changeable due to the many seals and writing inks available in the market. This study determines the line-crossing sequence of stamping before writing by observing the influence of seal ink on pen writing. The results of examining four types of pens and six types of seal ink crossings reveal that assessing the completeness of writing strokes can determine sequencing. Different ink types interact to produce different phenomena. In addition, time interval and pen structure affected the interaction between two inks in a crossing. A 70% accuracy rate was achieved in a nationwide blind test, which will be discussed in this article.

Badly burned skeletal remains are commonly submitted to forensic laboratories for victim identification via DNA analysis methods. Burned skeletal remains present many challenges for DNA analysis as they can contain low amounts of DNA which can also be damaged and degraded, resulting in partial or no STR profiles. Therefore, a simple, but effective screening method that identifies which samples may provide the most successful STR or mtDNA typing results for identification would enable forensic laboratories to save time, money, and resources. One metric that can be used and a screening method is the color of burned bone, as bone color changes with exposure to fire as temperature and length of exposure increase. This research developed a quantitative screening method based on the surface color of burned bone. The different visual bone colors (light brown, dark brown, black, gray, and white) were quantified using the Commission on Illumination L*a*b color space. These values were then compared to DNA yield, STR, and mtDNA profile completeness to identify whether the L*a*b values can predict genotyping success. A Bayesian network was constructed to determine the probability of STR typing success, given a set of L*a*b values. Results demonstrated that samples with an a* value greater than or equal to one and b* value greater than eight (light brown and dark brown burned samples) were the most predictive of STR typing success and mtDNA typing success. A decision tree for processing burned bones was constructed based on the color value thresholds.

The conventional methamphetamine (MA) detection method using the Simon reaction can be affected by false positives owing to compounds similar to aliphatic secondary amines. In this study, we examined the new Simon reaction to improve the qualitative accuracy of MA detection to discriminate substances that give false positives in a conventional Simon reaction. After the conventional Simon reaction for MA and false positives (N-isopropylbenzylamine (NIP-BA), N-methylbenzylamine (NMe-BA), L-proline (Pro), and L-hydroxyproline (HYP)), which are colored blue, di-tert-butyl dicarbonate (t-Boc) reagent was added, and color tone changes were observed. When t-Boc was added to the false positives (NIP-BA, NMe-BA, Pro, and HYP), the colors of MA, Pro, and HYP changed to purple; NIP-BA changed to blue; and NMe-BA changed to light pink after 3 min. These results suggested that MA can be differentiated from NIP-BA and NMe-BA. Furthermore, the solid-phase chromogenic method was examined, and it was confirmed that MA could be differentiated from Pro and HYP. The method developed in this study should increase the accuracy of MA appraisal at crime scenes and contribute to the reduction of misclassifications arising from false-positive substances.

Forensic document examiners are often confronted with questioned documents written with ballpoint pens. Depending on the force applied (or pressure) as well as the angle between the pen and the surface, sister lines running parallel to the inked strokes can be left by the lip of the housing ball. In a real case, sister lines were observed on the left side of inked strokes of a questioned signature. To assess whether the writer of that signature was a left-handed or a right-handed writer based on this result, an experimental study was carried out. Handwritten samples and signatures from 182 right-handed and 18 left-handed writers were collected with different ballpoint pens. For every writer, the presence or absence of sister lines was recorded. Sister lines were observed in 49% of the writers of the studied population (in 50% of the right-handed and ca. 39% of the left-handed writers). Most individuals who left sister lines showed a writing angle of 50°–55°. The location of sister lines was tabulated to inform probabilities of observing sister lines at a given location, if the writer is a right-handed or left-handed writer. In the case at hand, a likelihood ratio of 48 was obtained in support of the proposition of a left-handed writer, rather than a right-handed writer. Applying Bayes' theorem, such value moves the prior probability of 15% that the writer of the questioned signature is left-handed to a posterior probability of 89%.

The detection of explosives and explosive devices based on the volatile compounds they emit is a long-standing tool for law enforcement and physical security. Toward that end, solid-phase microextraction (SPME) combined with gas chromatography–mass spectrometry (GC–MS) has become a crucial analytical tool for the identification of volatiles emitted by explosives. Previous SPME studies have identified many volatile compounds emitted by common explosive formulations that serve as the main charge in explosive devices. However, limited research has been conducted on initiators like fuses, detonating cords, and boosters. In this study, a variety of SPME fiber coatings (i.e., polydimethylsiloxane (PDMS), polydimethylsiloxane/divinylbenzene (PDMS/DVB), divinylbenzene/carboxin/polydimethylsiloxane (DVB/CAR/PDMS), and carboxin/polydimethylsiloxane (CAR/PDMS)) were employed for the extraction and analysis of volatiles from Composition C-4 (cyclohexanone, 2-ethyl-1-hexanol, and 2,3-dimethyl-2,3-dinitrobutane (DMNB)) and Red Dot double-base smokeless powder (nitroglycerine, phenylamine). The results revealed that a PDMS/DVB fiber was optimal. Then, an assortment of explosive items (i.e., detonation cord, safety fuse, slip-on booster, and shape charge) were analyzed with a PDMS/DVB fiber. A variety of volatile compounds were identified, including plasticizers (tributyl acetyl citrate, N-butylbenzenesulfonamide), taggants (DMNB), and degradation products (2-ethyl-1-hexanol).