Journal of forensic sciences最新文献

Vertebrate scavengers represent important taphonomic agents that can act on a body, particularly when in an outdoor environment. Understanding the effects of these agents will direct how and where to search for human remains and influence the likelihood of discovery in a particular region. The current study aimed to identify the taphonomic impact of scavenger guilds in the peri-urban and rural regions of southeastern British Columbia. Vertebrate scavenger activity on pig carcasses was recorded remotely using trail cameras and analyzed to determine temporal scavenging profiles. Both the peri-urban and rural environments produced comparable scavenger guilds, namely: turkey vultures, American crows/northern ravens (classified as “corvids”), American black bears, and coyotes. Although the two locations had different study lengths due to variable degrees of scavenging, for the period that was common to both locations (summer to early fall), the black bear was the most frequent scavenger followed by coyote. However, the dispersal of remains by the mammalian scavengers was distinctly different between sites. Only 12%–33% of skeletal elements were recovered at the rural sites compared to 80%–90% recovered at the peri-urban sites, even though the latter sites had a longer study timeframe. The extended timeframe of the peri-urban sites confirmed that certain scavengers (e.g., turkey vultures and black bears) are only seasonally active in this region. These findings demonstrate the variability of scavenger behavior and the need to assign caution and local ecological knowledge when predicting scavenger trends. Such taphonomic information is relevant for human remains searches in regions with comparable scavenger guilds.

Forensic entomology plays an important role in medicolegal investigations by using insects, primarily flies, to estimate the time of colonization. This estimation relies on the development of the flies found at the (death) scene and can be affected (and sometimes corrected) by external factors, such as temperature and humidity, and internal factors, such as species and sex. This study leverages infrared (IR) spectroscopy combined with machine learning models—Partial Least Squares Discriminant Analysis (PLS-DA) and eXtreme Gradient Boosting trees Discriminant Analysis (XGBDA)—to differentiate between male and female Cochliomyia macellaria larvae, commonly found on human remains. Significant vibrational differences were detected in the infrared spectra of third instar C. macellaria larvae, with distinct peaks showing variations in relative absorbance between sexes, suggesting differences in biochemical compositions such as cuticular proteins and lipids. The application of PLS-DA and XGBDA yielded high classification accuracies of about 94% and 96%, respectively, with female spectra consistently having higher sensitivity than males. This non-destructive approach offers the potential to refine supplemental post-mortem interval estimations significantly, enhancing the accuracy of forensic analyses.

Forensic examiners make important decisions to address legal questions, yet there is now ample evidence that their decisions can be subjective and inconsistent. This commentary suggests that elements of deliberate practice may help in not only having more consistent forensic decisions but also toward expected accuracy. Specifically, four elements of deliberate practice: (1) setting a goal, (2) motivation, (3) feedback, and (4) repetition are outlined with examples for addressing issues of cognitive bias and managing stress at work. If any of these elements are missing, such as delayed or no feedback, then suboptimal or no improvement of examiners' decision-making may result. This tool for deliberately improving decision-making may be applicable to other legal professionals; thus, potentially driving policies that may help enhance the criminal justice system broadly.

Indra L, Giles S, Alfsdotter C, Errickson D, Lösch S. Evaluation of porcine decomposition and total body score (TBS) in a central European temperate forest. J Forensic Sci. 2024;6(3):784–97. https://doi.org/10.1111/1556-4029.15497.

Tables 3 and 4 contain errors. The partial body score numbering of sections C and D of both tables is not continuous. Table 3 should have 6pts, 7pts, and 8pts in section C, and then 9pts, 10pts, 11pts, and 12pts in section D. Table 4 should have 6pts and 7pts in section C, and then 8pts and 9pts in section D. The correct tables are provided below.

We apologize for these errors.

This study examined how variations in signature complexity affected the ability of forensic document examiners (FDEs) and laypeople to determine whether signatures are authentic or simulated (forged), as well as whether they are disguised. Forty-five FDEs from nine countries evaluated nine different signature comparisons in this online study. Receiver Operating Characteristic (ROC) analyses revealed that FDEs performed in excess of chance levels, but performance varied as a function of signature complexity: Sensitivity (the true-positive rate) did not differ much between complexity levels (i.e., 65% vs. 79% vs. 79% for low vs medium vs high complexity), but specificity (the true-negative rate) was the highest (95%) for the medium complexity signatures and lowest (73%) for low complexity signatures. The specificity of high-complexity signatures (83%) was between these values. The sensitivity for disguised comparisons was only 11% and did not vary across complexity levels. One hundred-one novices also completed the study. A comparison of the area under the ROC curve (AUCs) revealed that FDEs outperformed novices in medium and high-complexity signatures but not low-complexity signatures. Novices also struggled to detect disguised signatures. While these findings elucidate the role of signature complexity in lay and expert evaluations, the error rates observed here may differ from those in forensic practice due to differences in the experimental stimuli and circumstances under which they were evaluated. This investigation of the role of signature complexity in the evaluation process was not intended to estimate error rates in forensic practice.

Alcohol calculations are carried out in many forensic case types. On occasion, individuals under the age of 18 are involved, and alcohol calculations may be beneficial. To date, there are no studies that have determined the best way to estimate total body water (TBW) or alcohol elimination rates in juveniles for alcohol calculations. We utilized a data set of 207 females and 218 males, aged 3–18 years, from a variety of ethnic backgrounds, where TBW had been empirically measured, to evaluate the best anthropometric equation to use to estimate TBW in juveniles. For males aged 3–15 years and females aged 2–13 years, the equation of Wells et al. was the most accurate and precise (RMSE of ≤10.4% in males and ≤9.9% in females). For males aged 16+ years and females aged 14+ years, the equation of Watson et al. was more appropriate (RMSE ≤11.5% and ≤12.4%, respectively). Based on published studies where the alcohol elimination rate was determined in 43 juveniles (aged 10-17 years) who were hospitalized due to alcohol consumption, a mean alcohol elimination rate of 16 mg/100 mL/h should be used. The recommended range being 9–25 mg/100 mL (5th–95th percentile). This study provides evidence that there are valid anthropometric equations to determine TBW and alcohol elimination rates that can be used for alcohol calculations in juveniles between the ages of 10 and 17.

Self-induced extreme intoxication akin to automatism (SIEA) is a complicated and controversial legal concept resistant to jurisdictional consensus. In the United States, SIEA has, at times, been considered under the concept of “settled insanity.”. In the United Kingdom, the defense may be allowed for specific intent crimes, though the defendant's awareness of the foreseeability of risk is addressed at trial. In Canada, recent jurisprudence has led to legal and practice landscape changes related to self-induced extreme intoxication. Here, we provide an overview of automatism and an update on the Canadian perspective with a review of the facts and an analysis of the Supreme Court of Canada's landmark decision in R v. Brown, where the court permitted the SIEA defense to be utilized for general intent crimes and acquitted Matthew Winston Brown, a 26-year-old male with no history of mental illness, with respect to two counts of “break and enter” and one count of “aggravated assault.” We review the social and legislative response to the changing case law as well as related implications for expert testimony, which may be provided by forensic mental health professionals. Given the judicial and legal implications of the recent changes for both perpetrators and victims of violent crime and given the dynamic international landscape on extreme intoxication in criminal law, the review is thought to be of interest to a broad category of stakeholders including policymakers and those working in forensic psychiatry and law.

The complexity of the drug market and the constant updating of drugs have been challenging issues for drug regulatory authorities. With the emergence of new psychoactive substances (NPS) and the nonmedical use of prescription drugs, forensic and toxicology laboratories have had to adopt new drug screening methods and advanced instrumentation. Using high-performance liquid chromatography coupled with Orbitrap mass spectrometry, we developed a screening method for common NPS and other drugs. Two milliliters of mixed solvent of n-hexane and ethyl acetate (1:1, v:v) were added to 500 μL of blood or urine sample for liquid–liquid extraction, and methanol extraction was used for hair samples. The developed method was applied to 3897 samples (including 332 blood samples, 885 urine samples, and 2680 hair samples) taken from drug addicts in a province of China during 2019–2021. For urine and blood samples, the limits of detection (LODs) ranged from 1.68 pg/mL to 10.7 ng/mL. For hair samples, the LODs ranged from 3.30 × 10⁻⁵ to 4.21 × 10⁻³ ng/mg. The matrix effects of urine, blood, and hair samples were in the range of 47.6%–121%, 39.8%–139%, and 6.35%–118%, respectively. And the intra-day precision was 3.5%–6.0% and the inter-day precision was 4.18%–9.90%. Analysis of the actual samples showed an overall positive detection rate of 58.9%, with 5.32% of the samples indicating the use of multiple drugs.