A study of DNA transfers onto plastic packets placed in personal bags

The ability to detect low level DNA brings with it the uncertainty of whether the detected DNA is a result of transfer. To address this uncertainty, a simulation study was conducted in which a mock illicit drug packet was placed into the personal bags of individuals. When the average transit time of the packets was increased from around 2 h to more than 14 h, the percentage of the DNA profiles recovered from the packets which could be attributed to the individuals increased greatly from 5.3% to 48.6%. We found that drug packers who were poor shedders could not be included as contributors to the DNA profiles from the drug packets at all and there was a higher chance that individuals other than themselves could be included as contributors to the DNA profile recovered from drug packets. We also found that it was equally likely that the drug packers who had direct contact with the drug packets and bag owners who did not, could be included as contributors to the DNA profiles recovered from the packets. The results in this study highlight the importance of taking into consideration the transit time of drug packet, the shedder status of the alleged packer and the history of an item, when evaluating DNA evidence in the context of illicit drug activities.     

Determining the Refractive Index Variation within Panes of Vehicle Windshield Glass

Refractive indices of seven double‐paned vehicle windshields were measured to assess the variation across the pane of glass and to evaluate collection techniques for known glass standards by comparing false negative rates. Measurements were made using a Foster and Freeman GRIM3 instrument, and a minimum of 240 measurements were made per pane. The mean SD of the windshields was 0.00004. It was further determined that collecting a known sample from two different sections of a shattered windshield gave the lowest rate of false negatives when using ± 2 standard deviations to estimate the RI variation of the known glass. Additionally, refractive indices often were highest in the center of the windshield and decreased toward the left and right edges; in approximately half the sample set, the two panes of a single windshield were differentiated by one or more properties.     

UNPACKING THE BLACK BOX OF PEER SIMILARITY IN DEVIANCE: UNDERSTANDING THE MECHANISMS LINKING PERSONAL BEHAVIOR,PEER BEHAVIOR,AND PERCEPTIONS

The strong correlation between measures of personal and peer deviance occurs with near “law‐like” regularity. Yet, as with other manifestations of peer similarity (often referred to as homophily), the mechanisms generating this relationship are widely debated. Specific to the deviance literature, most studies have failed to examine, simultaneously, the degree to which similarity is the consequence of multiple causes. The current study addresses this gap by using longitudinal network data for 1,151 individuals from the Netherlands Institute for the Study of Crime and Law Enforcement (NSCR) School Project. Structural equation modeling is used to address these issues by adapting Jussim and Osgood's ( 1989 ) model of deviant attitudes in dyadic pairs to the current data. Across two separate behavioral domains (substance use and property offending), the results provide strong support for the prediction that individuals project their own deviant tendencies inaccurately onto their peers. Conversely, the results provide little or no support for the predictions that respondents accurately perceive their peers’ deviance or that their perceptions of peer deviance influence their own behavior. Implications for understanding the role of peer behavior in the etiology of adolescent deviance are discussed.     

道路交通事故速度重建技术现状

事故车辆行驶速度是道路交通事故调查的重要内容,也是公安交通管理部门进行事故认定,法院进行司法审判的关键技术依据。目前事故车辆行驶速度调查的主要途径是办案单位委托具有专业技术能力的司法鉴定机构进行速度重建,使用的方法主要有基于事故形态的速度重建、基于模拟软件的速度重建、基于车载记录数据的速度重建和基于视频图像的速度重建。通过从速度重建的技术发展、执业类别和能力验证等方面介绍了我国道路交通事故速度重建技术的发展现状。     

道路交通事故痕迹鉴定中常见问题分析

道路交通事故痕迹鉴定是道路交通事故技术鉴定中的重要鉴定项目之一,也是道路交通事故技术鉴定其他鉴定项目的基础,除应用手、足、工、枪、特等刑事技术传统痕迹的基础理论和方法外,还需要结合力学、道路工程学、道路安全学、车辆工程学、法医学等多学科知识综合评判的一门鉴定科学门类。道路交通事故痕迹鉴定的步骤主要分为合同评审、痕迹勘验、比对分析、作出评判、形成文书五个方面,在其发展的十几年时间里,出现了许多亟待解决的问题,根据道路交通事故痕迹鉴定实践工作中遇到的常见问题,重点归纳这些问题并提出解决方案。     

植物DNA检验技术在命案现场重建中的应用策略

植物DNA检验技术是利用植物遗传性状的稳态性对关联植物物证进行检验鉴定的手段。将该技术应用于现场重建,应基于植物物证与犯罪嫌疑人、被害人及其活动环境具有＂重大关联性＂。从命案现场重建的需求上看,应围绕犯罪嫌疑人及其可控物品中附着植物与现场植物的种属同一性判断、被害人尸体（尸块或尸骸）及其随附物品中附着植物与中心现场植物的种属同一性判断、疑似侵害物及其附着植物与嫌疑人行为关联植物的种属同一性判断等三个角度或层次进行检验和综合分析。植物DNA检验技术可阐明物证的时空运行停顿规律,为命案现场重建工作提供一种参考性解决方案。     

Ethical,legal, social,and policy issues in the use of genomic technology by the U.S. Military

Advances in genomic science are attracting the interest of the U.S. military for their potential to improve medical care for members of the military and to aid in military recruitment, training, specialization, and mission accomplishment. While researchers have explored the ethical, legal, and social issues raised by the use of genomic science in a wide variety of contexts, there has been virtually no examination of these issues in connection with the use of genomics by the military. This article identifies potential uses of genomic science by the military, proposes an applicable ethical and legal framework, and applies the framework to provide ethical and legal guidance for military decision-makers.     

Medical examiner response to the drug overdose epidemic in King County Washington: “Real-time” surveillance,data science,and applied forensic epidemiology

As the overdose epidemic overwhelmed medicolegal death investigation offices and toxicology laboratories, the King County Medical Examiner's Office responded with “real-time” fatal overdose surveillance to expedite death certification and information dissemination through assembling a team including a dedicated medicolegal death investigator, an information coordinator, and student interns. In-house testing of blood, urine, and drug evidence from scenes was performed using equipment and supplies purchased for surveillance. Collaboration with state laboratories allowed validation. Applied forensic epidemiology accelerated data dissemination. From 2010 to 2022, the epidemic claimed 5815 lives in King County; the last 4 years accounted for 47% of those deaths. After initiating the surveillance project, in-house testing was performed on blood from 2836 decedents, urine from 2807, and 4238 drug evidence items from 1775 death scenes. Time to complete death certificates decreased from weeks to months to hours to days. Overdose-specific information was distributed weekly to a network of law enforcement and public health agencies. As the surveillance project tracked the epidemic, fentanyl and methamphetamine became dominant and were associated with other indicators of social deterioration. In 2022, fentanyl was involved in 68% of 1021 overdose deaths. Homeless deaths increased sixfold; in 2022, 67% of 311 homeless deaths were due to overdose; fentanyl was involved in 49% and methamphetamine in 44%. Homicides increased 250%; in 2021, methamphetamine was positive in 35% of 149 homicides. The results are relevant to the value of rapid surveillance, its impact on standard operations, selection of cases requiring autopsy, and collaboration with other agencies in overdose prevention.     

What does method validation look like for forensic voice comparison by a human expert?

Method validation has gained traction within forensic speech science. The community recognises the need to demonstrate that the analysis methods used are valid, but finding a way to do so has been more straightforward for some analysis methods than for others. This article addresses the issue of method validation for the Auditory Phonetic and Acoustic (AuPhA) approach to forensic voice comparison. Although it is possible to take inspiration from general regulatory guidance on method validation, it is clear that these cannot be transposed on to all forensic analysis methods with the same degree of success. Particularly with respect to an analysis method like AuPhA, and in a field of the size and characteristics of forensic speech science, a bespoke approach to method validation is required. In this article we address the discussions that have been taking place around method validation, and illustrate one possible solution to demonstrating the validity of voice comparison by a human expert using the AuPhA method. In doing so we consider the constraints placed on sole practitioners, which generally go unacknowledged.     

Nondestructive Biological Evidence Collection with Alternative Swabs and Adhesive Lifters

In forensic science, biological material is typically collected from evidence via wet/dry double swabbing with cotton swabs, which is effective but can visibly damage an item's surface. When an item's appearance must be maintained, dry swabbing and tape‐lifting may be employed as collection techniques that are visually nondestructive to substrates' surfaces. This study examined the efficacy of alternative swab matrices and adhesive lifters when collecting blood and fingerprints from glass, painted drywall, 100% cotton, and copy paper. Data were evaluated by determining the percent profile and quality score for each STR profile generated. Hydraflock^® swabs, BVDA Gellifters^®, and Scenesafe FAST? tape performed as well as or better than cotton swabs when collecting fingerprints from painted drywall and 100% cotton. Collection success was also dependent on the type of biological material sampled and the substrate on which it was deposited. These results demonstrated that alternative swabs and adhesive lifters can be effective for nondestructive DNA collection from various substrates.