The Development and Application of Random Match Probabilities to Firearm and Toolmark Identification

The field of firearms and toolmark analysis has encountered deep scrutiny of late, stemming from a handful of voices, primarily in the law and statistical communities. While strong scrutiny is a healthy and necessary part of any scientific endeavor, much of the current criticism leveled at firearm and toolmark analysis is, at best, misinformed and, at worst, punditry. One of the most persistent criticisms stems from the view that as the field lacks quantified random match probability data (or at least a firm statistical model) with which to calculate the probability of a false match, all expert testimony concerning firearm and toolmark identification or source attribution is unreliable and should be ruled inadmissible. However, this critique does not stem from the hard work of actually obtaining data and performing the scientific research required to support or reject current findings in the literature. Although there are sound reasons (described herein) why there is currently no unifying probabilistic model for the comparison of striated and impressed toolmarks as there is in the field of forensic DNA profiling, much statistical research has been, and continues to be, done to aid the criminal justice system. This research has thus far shown that error rate estimates for the field are very low, especially when compared to other forms of judicial error. The first purpose of this paper is to point out the logical fallacies in the arguments of a small group of pundits, who advocate a particular viewpoint but cloak it as fact and research. The second purpose is to give a balanced review of the literature regarding random match probability models and statistical applications that have been carried out in forensic firearm and toolmark analysis.     

Race and General Strain Theory: Microaggressions As Mundane Extreme Environmental Stresses

This article spotlights racial microaggressions as relevant for understanding delinquency and the race gap in offending among middle-schoolers. In doing so, we draw on an emerging body of delinquency research rooted in general strain theory that demonstrates the emotional and behavioral tolls of face-to-face discrimination. We contend that this body of research has not established the full impact of racial microaggressions on delinquency because it has not considered that the specter of microaggressive encounters follows African American youth in particular from experience to experience. Specifically, we propose that racial microaggressions influence juvenile offending both directly—as previously documented—and by exacerbating the impact of co-occurring stressful events and experiences on negative emotions and delinquency. Using data collected at a southeastern middle-school, we find support for this proposition, empirically documenting that racial microaggressions interact with co-occurring stressful experiences in OLS models predicting delinquency.     

Bruise Documentation,Race and Barriers to Seeking Legal Relief for Intimate Partner Violence Survivors: a Retrospective Qualitative Study

Documentation of physical injuries from intimate partner violence (IPV) is critically important when a victim seeks legal help. Bruising, a common IPV injury, is often less visible on victims of color. This retrospective qualitative study is focused on IPV survivors’ and service providers’ experiences with the complex interrelationship between IPV injury, bruise documentation, race and legal assistance. Focus group results with a racially diverse group of female IPV survivors and legal service providers indicate that all victims struggle with documenting their bruises, but for women of color, even documentation of visible bruising underrepresents the severity of their IPV injuries. Further, there are a number of social, logistic, and systemic barriers to injury documentation that may make legal relief for IPV difficult for all women, but particularly more difficult for women of color. Proposed solutions to address the gap include, improved documentation techniques, and greater education for legal service providers. Implications for the field of family violence generally and potential future research directions are also discussed.     

Evaluation of the rapid analyte measurement platform (RAMP) for the detection of Bacillus anthracis at a crime scene

The aim of this study was to evaluate the accuracy and reliability of the rapid analyte measurement platform (RAMP) for presumptive identification of Bacillus anthracis spores. Test samples consisted of serial dilutions of spore preparations of several Bacillus species, including B. anthracis, which were tested, using the RAMP Anthrax test cartridge, according to the manufacturer's instructions. The fluorescence labelled antibody-antigen complexes were detected in the portable reader after 15 min following sample addition. Dilutions of common environmental and household powders were also tested to identify possible false positive results. B. anthracis spores were identified reliably in test samples containing more than 6000 spores. The test kits were highly specific, showing no cross reactivity with other Bacillus species or any environmental powders tested. The RAMP system for detection of B. anthracis spores, from environmental samples, showed consistent results under a variety of analytical conditions, enabling the trained user to provide a rapid, accurate preliminary risk assessment of a suspected bioterrorism incident.     

Fentanyl concentrations in 23 postmortem cases from the hennepin county medical examiner's office

The purpose of this study was to compare blood fentanyl concentrations in fentanyl-related deaths with fentanyl concentrations found incidentally at autopsy, as well as with fentanyl concentrations found in hospitalized patients receiving fentanyl. Between the years 1997 to 2005, 23 fentanyl-positive postmortem cases were identified. Nineteen of 23 (82.6%) cases were deemed to be drug overdoses. Fentanyl alone was responsible for 8 of the 19 (42.1%) overdose deaths. Mean and median fentanyl concentrations were 36 (SD 38) microg/L and 22 microg/L, respectively, range 5-120 microg/L. Seven of the cases were accidental, one undetermined. The remaining 11 of the 19 (57.9%) cases were mixed drug overdoses. Fentanyl concentrations in these cases were 31 (SD 46) microg/L, range 5-152 microg/L. All of the mixed drug overdoses were determined to be accidental. Four cases where fentanyl was considered an incidental postmortem finding were determined to be natural deaths. In hospitalized inpatients (n = 11) receiving fentanyl 2 of the patients receiving fentanyl for chronic pain for more than 3 months had concentrations of 8.5 microg/L and 9.9 microg/L. The other nine inpatient concentrations were less than 4 microg/L. In conclusion, blood fentanyl concentrations found in cases where fentanyl alone was determined to be the cause of death were similar to cases where fentanyl was part of a mixed drug overdose. There was also considerable overlap between fentanyl concentrations in fentanyl-related overdose deaths compared to hospitalized patients being treated for chronic pain. Fentanyl concentrations in postmortem cases must be interpreted in the context of the deceased's past medical history and autopsy findings.     

Crisis (hostage) negotiators weigh in: the skills,behaviors, and qualities that characterize an expert crisis negotiator

This research identified what skills, behaviors, and qualities experienced crisis (hostage) negotiators believe enhance or harm their success during negotiation. 188 negotiators from various countries (primarily United States) voluntarily completed an online survey in which they listed the aforementioned characteristics and reported on various aspects of their own background and behaviors. Open-response questions were coded and quantitative methods revealed what qualities were listed most frequently by negotiators. Active listening, displays of empathy, effective communication, and remaining calm and collected appear at the top of their to-do lists. Conversely, being confrontational, arguing, yelling, and interrupting were reported as behaviors to be avoided. Most negotiators attend trainings multiple times a year and read on the topic of crisis negotiation. About half follow a model during negotiations, typically the FBI’s Behavioral Change Stairway Model. Findings are discussed with relevance to future research directions and improvement of negotiator trainings.     

Sibling Incest: A Model for Group Practice with Adult Female Victims of Brother–Sister Incest

Working with groups of people who have been sexually abused introduces mutual experiential themes into the process that can be beneficial and meaningful. This paper discusses brother–sister incestuous sexual abuse with implications for group work. Literature and research is reviewed concerning sexual abuse, incest, family relationships, and theories that aid in explaining incest. Themes covered include: effects of incest, coping methods, blaming, and family of the victim. Common themes are explored and implications for group work are suggested on the basis of length, detail, structure, content, and pre-group contact.     

Radiological determination of the cranial index of present-day Ghanaians

The cranial index (CI) of Ghanaians is currently unknown. The aim of this study was to measure the CI in a population of Ghanaians in order to classify them against pre-determined CI categories. A systematic random sampling method was used to select 300 normal computed tomography (CT) head scans of adult Ghanaians from the largest hospital in Ghana. All patients were deemed to have a normal cranial image configuration based on the radiological report. The biparietal diameter (BPD, width) and the occipitofrontal diameter (OFD, length) were measured on transaxial CT images using a workstation with a calibrated measurement calliper tool. The CI ratio was calculated as the BPD multiplied by 100 and divided by the OFD. Mean, standard deviation (SD) and range were calculated for BPD, OFD and CI. Differences in measurements between demographic groups were compared using an unpaired t-test, with test α set at 0.05. Of the population of Ghanaians included in this study, 165 (55%) were male and 135 (45%) were female. The mean CI was 77.3 ± 3.6 in males and 79.0 ± 3.3 in females, placing both genders in the mesocephalic category. However, the difference between males and females was found to be statistically significant (P = 0.02). The study indicated that most Ghanaian adults belong to the mesocephalic category of CI. Females also had a higher CI, which could be used to differentiate gender groups. This information can be useful for forensic medicine, plastic surgeries for clinical and research purpose.

Key points

• This study found the mean CI of adult Ghanaians to be 78.0 ± 13.0.
• This indicates that most Ghanaian adults belong to the mesocephalic category of CI.
• Females had a higher CI, which could be used to differentiate gender groups.
• To the best of our knowledge, this is the first study which assessed CI of Ghanaians using CT scan.