Validating TrueAllele® Interpretation of DNA Mixtures Containing up to Ten Unknown Contributors

Most DNA evidence is a mixture of two or more people. Cybergenetics TrueAllele^® system uses Bayesian computing to separate genotypes from mixture data and compare genotypes to calculate likelihood ratio (LR) match statistics. This validation study examined the reliability of TrueAllele computing on laboratory-generated DNA mixtures containing up to ten unknown contributors. Using log(LR) match information, the study measured sensitivity, specificity, and reproducibility. These reliability metrics were assessed under different conditions, including varying the number of assumed contributors, statistical sampling duration, and setting known genotypes. The main determiner of match information and variability was how much DNA a person contributed to a mixture. Observed contributor number based on data peaks gave better results than the number known from experimental design. The study found that TrueAllele is a reliable method for analyzing DNA mixtures containing up to ten unknown contributors.     

Testing hot-spots police patrols against no-treatment controls: Temporal and spatial deterrence effects in the London Underground experiment

Our understanding of causality and effect size in randomized field experiments is challenged by variations in levels of baseline treatment dosage in control groups across experiments testing similar treatments. The clearest design is to compare treated cases with no-treatment controls in a sample that lacks any prior treatment at baseline. We applied that strategy in a randomized test of hot-spots police patrols on the previously never-patrolled, track-level platforms of the London Underground (LU). In a pretest–posttest, control-group design, we randomly assigned 57 of the LU's 115 highest crime platforms to receive foot patrol by officers in 15-minute doses, 4 times per day, during 8-hour shifts on 4 days a week for 6 months. The effect of 23,272 police arrivals at the treatment hot spots over 26 weeks was to reduce public calls for service by 21 percent on treated platforms relative to controls, primarily when police were absent (97 percent of the measured effect). This effect was six times larger than the mean standardized effect size found in the leading systematic review. This finding provides a benchmark against the baseline counterfactual of no patrol in hot spots, with strong evidence of residual deterrence and no evidence of local displacement.     

Importance and Approach to Manner of Death Opinions in Opioid-Related Deaths

The majority of opioid-related deaths are accidental. However, the number of opioid-related suicidal deaths is likely under recognized. Presented here is a case of suicide by heroin overdose. The manner of death would have likely been deemed accidental if not for critical information shared by the decedent’s family during follow-up telephone interviews between the forensic pathologist and the decedent’s family, which included text messages that were sent by the decedent just before his death that were not known at the time of the initial medicolegal death scene investigation. This case highlights that when a forensic pathologist establishes an engaged relationship with the decedent’s family, the information elucidated can prove to be invaluable in reaching an informed opinion about the manner of death. For overdose cases, identifying an accurate manner of death allows the design of public health efforts that adequately address the health risks in the community. For aid in the determination of the manner of death for overdose cases, we propose a five-step checklist that may assist forensic pathologists and medicolegal death investigators when approaching similar cases.     

Results of the 2018 Rapid DNA Maturity Assessment

Three commercially available integrated rapid DNA instruments were tested as a part of a rapid DNA maturity assessment in July of 2018. The assessment was conducted with sets of blinded single-source reference samples provided to participants for testing on the individual rapid platforms within their laboratories. The data were returned to the National Institute of Standards and Technology (NIST) for review and analysis. Both FBI-defined automated review (Rapid DNA Analysis) and manual review (Modified Rapid DNA Analysis) of the datasets were conducted to assess the success of genotyping the 20 Combined DNA Index System (CODIS) core STR loci and full profiles generated by the instruments. Genotype results from the multiple platforms, participating laboratories, and STR typing chemistries were combined into a single analysis. The Rapid DNA Analysis resulted in a success rate of 80% for full profiles (85% for the 20 CODIS core loci) with automated analysis. Modified Rapid DNA Analysis resulted in a success rate of 90% for both the CODIS 20 core loci and full profiles (all attempted loci per chemistry). An analysis of the peak height ratios demonstrated that 95% of all heterozygous alleles were above 59% heterozygote balance. For base-pair sizing precision, the precision was below the standard 0.5 bp deviation for both the ANDE 6C System and the RapidHIT 200.     

Identification of Opioids and Related Substances using Handheld Raman Spectrometers

This study describes the performance of handheld Raman devices for detecting one hundred opioids and related substances including fentanyl and several analogs. Using a single “parent” device, signatures (spectra) with excellent signal-to-noise ratios were generated using <5 mg of most compounds. The signatures were added to a method (library), which was electronically transferred to three “daughter” devices. The devices were able to discriminate different salt forms and isomers. On average, the daughter devices yielded a true-positive rate of 97.3% for generating an alarm for opioids and were 93.3% effective for correctly identifying the opioid. The devices yielded true-negative, false-positive and false-negative rates of 100%, 0%, and 2.7%, respectively, where false negatives were due to weak signal and fluorescence. These data demonstrate that the parent-daughter electronic transfer method was successful and effective, which permits the ability to develop methods in the laboratory that can be seamlessly pushed out to field devices.     

Positional Asphyxia in Opioid-Related Deaths: Is It Being Overlooked?

The contribution of positional asphyxia in opioid-related deaths is currently unknown. Diagnostic criteria for positional asphyxia include finding the decedent in a position that does not allow for adequate respiration and an inability to extricate themselves from the position due to various conditions. Our primary objective was to assess whether positional asphyxia and the resulting airway compromise were a contributing factor to death due to the toxic effects of opioids. We evaluated 225 deaths where the death scene investigation contained adequate information to evaluate for positional asphyxia and performed a Pearson chi-square test to determine if the proportion of deaths found in an airway compromising position was higher when opioid(s) caused the death. The proportion of decedents found in a potential airway compromising position was greater when the death was related to opioid use (p < 0.0001). Further, narrowing the dataset to decedents who were definitely in an airway compromising position [Yes (24.49%) vs. No (11.02%)] showed a statistically significant association between positional asphyxia and deaths related to opioid use (p = 0.0021). Carefully documenting the position in which the decedent was initially found may be a significant factor in accurate reporting and in harm reduction efforts to decrease the opioid mortality rate.     

Blast Suppression Foam,Aqueous Gel Blocks,and their Effect on Subsequent Analysis of Forensic Evidence*

In addition to having blast mitigation properties, aqueous foam concentrate AFC-380 blast suppression foam is designed to capture aerosolized chemical, biological, and radioactive particles during render-safe procedures of explosive devices. Exposure to aqueous environments and surfactants may negatively affect forensic evidence found at the scene, but the effects of AFC-380 foam and aqueous gel on the preservation and subsequent analysis of forensic evidence have not previously been investigated. Sebaceous finger and palm prints and DNA samples on paper, cardboard, tape, and various metal and plastic items, along with hairs, carpet and yarn fibers, and inks and documents, were exposed to AFC-380 foam. Similar mock evidence was also exposed to a superabsorbent gel of the type found in aqueous gel blocks used for shrapnel containment. Exposure to foam or aqueous gel was associated with a dilution effect for recovered DNA samples, but quality of the samples was not substantially affected. In contrast, exposure to AFC-380 foam or gel was detrimental to development of latent finger and palm prints on any substrate. Neither the hair nor the fiber samples were affected by exposure to either the foam or gel. Indented writing on the document samples was detrimentally affected by foam or gel exposure, but not inks and toners. The results from this study indicate that most types of forensic evidence recovered after being exposed to aqueous gel or blast suppression foam can be reliably analyzed, but latent finger and palm prints may be adversely affected.     

Socially Demoralizing Environments and the Development of the Street Code from Childhood to Emerging Adulthood

This study examines hypotheses regarding patterns of developmental change in street code commitment from childhood through emerging adulthood. It tests whether street code commitment demonstrates developmental stability or if it fluctuates in response to evolving socially demoralizing conditions. Latent growth curve and parallel process models are applied to longitudinal data from an African American sample. Confirmatory factor analysis tests the degree to which neighborhood violence, peer processes, and family hostilities combine to form a latent construct of socially demoralizing environments. Analysis also tests measurement invariance across the study assessment periods. Street code commitment demonstrates a non-linear growth pattern across time. Commitment increases in childhood, peaks in late adolescence, and declines in emerging adulthood. Exposure to demoralizing social environments demonstrates a similar pattern of change characterized by a peak in adolescence followed by a gradual decline. Harsh childhood social environments affect the initial levels but not the growth of the street code. Street code commitment fluctuates in response to contemporaneous environmental conditions. The street code is malleable from childhood through emerging adulthood. Commitment to the street code is not a stable product of socialization or early childhood social environmental exposures. The degree to which individuals embrace the code is largely a function of their current social environment.     

Assessing the Impact of Knowledge and Location on College Students’ Perceptions of Gun Control and Campus Carry Policies: a Multisite Comparison

American Journal of Criminal Justice - Recent incidents of mass shootings in schools have raised questions about the availability of “military-style” firearms and need for campus carry...     

Defining Mediator Knowledge and Skills

A two-year collaboration among researchers, practitioners, and advisers from the major national organizations of mediators produced a job analysis relevant to mediators involved in interpersonal disputes (i.e., divorce, community, formal parent-child mediation, etc.). One byproduct of the job analysis is an extensive list of the knowledge areas and skills important to effective job performance. This essay defines the knowledge and skill areas that emerged from the analysis.