基于痕迹检验的交通事故再现鉴定案例分析

交通事故再现是确定交通事故责任和事故成因的方法之一。在利用事故再现仿真软件进行交通事故再现过程中,应以交通事故现场痕迹的客观事实为依据。结合一起汽车与两轮车碰撞的交通事故案例,通过交通事故现场痕迹检验,分析交通事故形态,确定相关仿真再现参数。利用PC-crash软件,建立汽车、两轮车和人体模型,进行事故重建,并利用路面痕迹、车体痕迹、人体痕迹等对再现结果进行了验证。在鉴定中将事故过程再现与现场痕迹鉴定结合起来,提高了交通事故鉴定的客观性和科学性。     

新冠疫情期间DNA虚拟仿真实验教学设计研究

生物物证技术在刑事侦查领域发挥着重要作用,DNA鉴定被称为新的破案法宝之一。但在现场实验教学中往往存在空间、时间有限等问题的限制,特别在新型冠状病毒疫情期间,现场DNA实验教学无法正常开展,限制了学生学习DNA相关理论知识的积极性,无法达到生物物证检验鉴定能力的培养要求。而虚拟仿真实验通过远程教学,可以解决以前及疫情期间实验教学中出现的问题,让学生对人类DNA提取与鉴定的流程及鉴定方法有更深层次的理解,提高实验教学效果。本文在DNA实验内容、仿真系统规格要求、功能要求、实施流程等方面进行设计,对前期的教学效果进行调查,最终结论认为DNA虚拟仿真实验在新冠疫情期间可以突破仪器设备和时空限制,实验教学中学生全流程全时段参与,建立"互联网+实验室"教学模式,促进实验教学资源开放共享。     

基于PC-Crash软件的道路交通事故再现技术研究进展

随着计算仿真技术和数字模拟技术的发展,运用数字化方法进行道路交通事故现场处理和过程分析逐渐替代了传统计算方法。其中PC-Crash软件仿真系统可对32辆以下的道路交通事故车辆进行再现,其再现准确度已经得到充分验证,并被交通警察部门和鉴定机构广泛使用。本文对PC-Crash软件用于道路交通事故再现的相关研究进行综述,探讨基于PC-Crash软件的道路交通事故再现技术在法医学实践中的应用及存在的一些问题,为道路交通事故仿真再现的研究与鉴定提供参考,同时为事故处理提供理论依据。     

1例杀人碎尸案的法医学现场分析

1案例资料2005年4月27、29日,5月2、6日在某河流不同河段分别发现了人体躯干上段、双上肢、双右小腿、1条左小腿、1块盆腔组织、1个人头。1.1现场勘验除“4.29”现场外,其余现场均位于一条河流的不同河段,“4.27”现场发现上段躯干,尸块南侧发现一袋口用绿色电线打死结捆绑的透明薄膜袋。“5.02”现场发现用50cm×40cm的黑色背包包装的人体臀部、会阴部及盆腔组织。“5.06”现场发现用3层“华润超市”购物袋包裹着的人头1个,已高度腐败。“4.29”现场位于某废水排泄沟内,发现1条右小腿及双上肢,手掌皮肤及指甲脱落,赤足。距该处北侧15.5m、3…     

案事件数据可视化研判平台的构建与应用展望

伴随信息化技术的普及,如何利用重大案事件现场勘查结果发掘要素关联关系及关键物证关联的外源信息,对现场勘查的调度指挥和定罪量刑具有极其重要的作用。作者在对国内外现场勘查技术的新进成果进行综述的基础上,以案事件要素关联机理为基准,现场要素可视化技术为核心,开展现场要素数据关联研判及可视化技术分类研究。本文从总体框架、功能模块、关联模式和方案设计等方面,介绍了现场勘验数据可视化展示与目标关联分析研判平台构建内容,并对研发出的案事件数据可视化研判平台的应用前景进行展望。     

论公共场所爆炸现场的快速处置与勘验

火车站等公共场所发生爆炸后,警方要采取应急警务对犯罪嫌疑人、受伤亡人员、现场秩序、痕迹物证保全与记录等开展快速处置与勘验。爆炸现场快速处置与勘验就是现场整体清理与转移,虽然现场的原始位置变化了,但是载体及其位置关系还在,特别是整体搬迁的残留物、抛出物等相互关系也要记录好。现场编号是勘查人员对现场的场所区域、痕迹物证分布、尸体位置等所做的标记,这种外在的符号添加和记录留存应该与现场客观记录的需要相匹配。     

犯罪现场方位拍照的方法

犯罪现场方位照相是为说明犯罪场所和环境的特点、季节、气候、犯罪地点方向、位置及现场与周围的关系,将其拍照下来的方法。 早期现场方位拍照较容易,选择一处较高较远且能显示现场及周围环境特点的位置进行拍照,用一张或几张照片的拼接即可将现场方位固定。现在,大批高层建筑的兴建给现场方位照相带来困难。具体表现在:(一)选择拍照点难。由于建筑物相互遮挡。选择远了无法拍照;选择近了     

关于加强灭火救援现场舆论引导的几点看法

随着网络信息的快速发展,灭火救援行动始终是舆论关注的焦点之一。成功的现场舆论引导和媒体管理可以弱化火灾对公众及媒体产生的消极影响,发挥媒体的积极作用,而建立、完善灭火救援现场媒体报道的管理机制,也是势在必行、行之有效的舆论管理方式。本文分析了公安消防部队目前在灭火救援现场宣传舆论工作的现状,提出了加强现场舆论引导及做好宣传报导工作的几项措施,旨在为规范和加强灭火救援现场的舆情工作提供一些合理化的意见建议。     

重视抛尸现场关联物品的检验

杀人抛尸现场的关联物品是指在抛尸现场与尸体有直接关联的物品，如凶手杀人所用的凶器、绳索及尸体上沾附的泥土、柴草和尸体包裹物(如麻袋、床单)或VI腔堵塞物等。由于抛尸现场不是杀人第一现场，多为偏僻的沟、井及庄稼田里等，故现场的发现较晚，甚至发现时尸体已高度腐败、腐烂，损伤特征及一些有价值的东西已不存在，失去了鉴定的意义；或遇     

嗜尸性昆虫证据在案发现场的分布研究

为了明确案发现场昆虫证据的分布,为法医昆虫学现场昆虫证据收集提供借鉴,我们利用猪尸体进行模拟,对现场昆虫的分布进行了调查,重点观察了大头金蝇、丝光绿蝇、绯颜裸金蝇、厚环黑蝇、阎甲科、隐翅甲科、埋葬甲科和皮蠹科昆虫的活动情况。结果表明,昆虫标本主要分布于尸体上及现场约10米范围的地面和地下,据此我们提出了法医昆虫学现场取样规范。     

The use of error rates to predict and characterize the efficacy of presumptive field tests

From a forensic perspective, a presumptive test, one which indicates the presence or absence of a certain target material such as blood, is an invaluable tool. Among these tests, there are different specificities, sensitivities, and shelf lives. The accuracy of a test is an algebraic combination of the specificity and sensitivity of the test. Each test has limitations as given by its false positive and false negative rates. The aim of this study was to illustrate how the false positive and false negative rates are to be properly determined using a simulation study for the phenolphthalein test. New presumptive tests must be properly evaluated/validated through testing of commonly encountered household items and other potentially probative items usually found at crime scenes, however, the makeup of test sets must appropriately capture all error rates. In order to correctly use these results when the test is applied to an unknown sample recovered at a crime scene, the error rates cannot be applied directly to estimate whether or not the sample is actually the analyte of interest. In a validation study, the forensic scientist calculates the false positive rate as the p(Positive Reaction|Blood), whereas at the scene, the crime scene investigator wishes to determine the p(Blood|Positive Reaction). All crime scene investigators need to ensure that the conditional is not transposed when interpreting such results. Furthermore, this work provides a model for the assessment of a multiple test diagnostic system intended for investigators.     

Swedish crime scene technicians: facilitations,epistemic frictions and professionalization from the outside

ABSTRACT

This article investigates the role of crime scene technicians in the Swedish criminal justice system, and particularly how Swedish crime scene technicians not only examine crime scenes but also facilitate the criminal justice system’s joint production of forensic evidence. It proposes thinking about the criminal justice system as a conglomeration of epistemic cultures, that is, of communities with different ways of producing and understanding forensic evidence. Such a perspective makes it possible to understand interprofessional frictions as epistemic frictions as well as to draw attention to the facilitations, mediations and translations that crime scene technicians perform. This perspective also makes it possible to illuminate how the crime scene technicians’ professionalization – a professionalization from the outside – affects both their future crime scene work and their facilitations.     

Victim's perceptions of initial police responses to robbery and aggravated assault: Does race matter?

Despite the fact that police officers are usually the first persons within the criminal justice system to respond to a criminal victimization, the majority of research investigating racial discrimination within the system has examined primarily the effects of race on adjudication outcomes which occur after initial police interventions, such as conviction decisions and sentences. Very little empirical effort has been devoted to examining the effects of race on early police responses to a reported victimization. Using data from the National Crime Victimization Survey from 1987 to 1992, this paper investigates the effects of both the victim's and the offender's race on three police responses to robbery and aggravated assault: (1) police response time to the scene, (2) effort exerted by the police at the scene, and (3) likelihood of arrest. It was found that police were quicker to respond and also exerted more effort at the scene such as searching and taking evidence to incidents of black on white robbery compared to all other racial dyads. This relationship held even after controlling for other factors such as victim-offender relationship, poverty, injury to the victim, and victim's gender. No significant effects of race, however, were found when predicting the probability of arrest in cases of robbery. The effects of race on police responses to aggravated assault were more complicated. For assaults involving strangers, police were significantly more likely to exert additional effort at the scene if the victim was white and the offender was perceived to be black. This effect was reversed, however, for nonstranger assault victimizations. Police were significantlyless likely to exert effort at the scene or to make an arrest in black on white assaults involving nonstrangers. The most consistent predictors of arrest in both stranger and nonstranger assault victimizations were police response time, injury to the victim, and the incident occurring in a public setting.     

Experimental forensic scenes for the characterization of ground-penetrating radar wave response

Over the last few decades, the use of non-intrusive geophysical techniques, which allows for coverage of an entire crime scene in a reasonable amount of time, in forensic investigation has increased. In this study, we analyze the effectiveness of ground-penetrating radar (GPR) in forensics. Experimental scenes were simulated and some of the most commonly buried items in actual crime scenes were introduced, such as bone remains, guns and drug caches. Later, a GPR survey was conducted on the experimental grids with a 500 MHz antenna. The final purpose was to characterize the radar wave response expected for each set of remains to assist with its identification in later actual investigations. The results collected provided promising information that can be used when surveying real cases. Nevertheless, there were some interpretational difficulties regarding the sizes of the items and the electromagnetic properties of the materials. For these cases, finite-difference time-domain modeling was employed to achieve an advanced interpretation of the field data. The simulated models used were built from accurate geometric data provided by photogrammetric methods, which replicate the experimental scenes in fine detail. Furthermore, this approach allowed for the simulation of more realistic models, and the synthetic data obtained provided valuable information for assisting in the interpretation of field data. As a result of this work, it was concluded that GPR can be an effective tool when searching for a variety of materials during a crime scene investigation.     

交通事故机动车驾驶人鉴定特点研究

遵循系统科学的原则,将交通事故机动车驾驶人鉴定作为一个体系来研究。机动车驾驶人鉴定的对象虽然是人,但应充分考虑人与车、人与路以及人与整个事故现场之间的关系,既要研究驾驶人自身,也要研究其反映形象以及相关的事实和现象。通过对事故现场、车辆、衣着、人体等要素进行观察和分析,尤其是对各要素之间的关联性和动态性分析,提出了综合鉴定机动车驾驶人的方法。     

足迹信息的计算机管理与查询

目的　根据国内足迹计算机管理系统的现状和需求 ,研制了适合我国刑侦工作特点的足迹管理与查询系统。方法　通过建立鞋厂鞋样、现场足迹和犯罪嫌疑人足迹数据库 ,利用足迹分析与比对软件进行管理和查询。结果　该软件完全能实现足迹管理计算机化 ,降低技术人员的劳动强度 ,提高足迹信息的使用率。结论　该软件使用方便快捷 ,适合推广使用     

Real-time forensic DNA analysis at a crime scene using a portable microchip analyzer

An integrated lab-on-a-chip system has been developed and successfully utilized for real-time forensic short tandem repeat (STR) analysis. The microdevice comprises a 160-nL polymerase chain reaction reactor with an on-chip heater and a temperature sensor for thermal cycling, microvalves for fluidic manipulation, a co-injector for sizing standard injection, and a 7-cm-long separation channel for capillary electrophoretic analysis. A 9-plex autosomal STR typing system consisting of amelogenin and eight combined DNA index system (CODIS) core STR loci has been constructed and optimized for this real-time human identification study. Reproducible STR profiles of control DNA samples are obtained in 2 h and 30 min with ≤0.8 bp allele typing accuracy. The minimal amount of DNA required for a complete DNA profile is 100 copies. To critically evaluate the capabilities of our portable microsystem as well as its compatibility with crime scene investigation processes, real-time STR analyses were carried out at a mock crime scene prepared by the Palm Beach County Sheriff's Office (PBSO). Blood stain sample collection, DNA extraction, and STR analyses on the portable microsystem were conducted in the field, and a successful “mock” CODIS hit was generated on the suspect's sample within 6 h. This demonstration of on-site STR analysis establishes the feasibility of real-time DNA typing to identify the contributor of probative biological evidence at a crime scene and for real-time human identification.     

The Effects of Substance Use on Offender Crime Scene Behavior

Abstract:  Substance use has an effect on an individual's propensity to commit acquisitive crime with recent studies showing substance users more likely to leave forensic material at a crime scene. An examination of acquisitive crime solved in Northamptonshire, U.K., during 2006 enabled 70 crime scene behavior characteristics to be analyzed for substance and nonsubstance use offenders. Logistical regression analyses have identified statistically significant crime scene behavior predictors that were found to be either present at or absent from the crime scene when the offender was a substance user. Most significant predictors present were indicative of a lack of preparation by the offender, irrational behavior, and a desire to steal high value, easily disposed of, property. Most significant predictors absent from the crime scene were indicative of more planning, preparation, and execution by the offender. Consideration is given to how this crime scene behavior might be used by police investigators to identify offenders.