血迹分析在现场血迹提取中的应用

对命案现场血迹的研究和分析历来是命案现场勘验及现场分析的重要组成部分。传统上,对现场血迹的研究分析侧重于对血迹形态及其形成过程的分析和研究,通过对现场血迹的分布规律及形态特征的观察和测量,判断血迹来源与形成机制,进而推断血迹与案件或犯罪事实之间的关系和过程[1]。     

血迹形态在命案现场中的应用1例

血迹是凶杀案件中最常见的痕迹物证之一。根据血迹的种类、数量、分布、形态、色泽、检验鉴定和形成方式等综合分析，可以对出血来源，出血部位，受伤时体位，受伤后的活动过程、案件性质、作案地点、作案时间、作案工具、作案人数和作案过程等做出推断，为侦察破案提供依据和证据支持。笔者通过详细的现场勘验，依据现场遗留血迹，分析血迹的形成方式和过程，来解读血迹中包含的犯罪信息。     

水泥地面上滴落状血迹形态的模拟实验

目的观察水泥地面上不同高度、速度对滴落状血迹的形态和大小,应用于现场勘验。方法采用等量抗凝人血,在静态和动态条件下,进行滴落状血迹的模拟实验,观察血迹的形态,测量其直径,用专业统计软件进行分析。结果在静态条件下,滴落状血迹呈圆形,其周围有毛刺状突起;滴落状血迹的大小(直径)与滴落高度之间有较好的线性关系,可得出回归方程。在慢走、急走、跑、快跑动态条件下,滴落状血迹为圆形或椭圆形,沿运动方向的一侧出现突起;高度、速度分别对血迹形态有影响,而且两者有交互作用。结论滴落状血迹形态和大小的观察和测量,可用推断出血部位的高度、运动速度和方向。     

动脉喷溅血迹动力学及形态学的模拟实验观察

目的观察不同压力、管径对在水平方向上形成的喷溅状血迹的喷射距离及形态的影响。方法建立室内现场环境,利用自制的模拟喷射装置,在60～210mmHg范围内设6种压力,在1.5～4.5mm范围内设4种管径条件,于50、100、150cm 3种高度,制作动脉喷溅血迹。观察水平面上不同喷射高度的喷溅血迹的分布范围、血迹大小及形态特征,并测量其距离,采用SPSS 13.0统计软件进分析,并进行方差检验。结果在不同高度,血液喷射距离随压力增大而增加,随管径增大而减小,两因素间存在交互作用,距离与压力及管径存在较好的线性关系,可得出回归方程。而喷溅血迹的形态特征总体趋势为:高度越高圆形血滴直径约大;管径越粗,边缘毛刺状突起越明显;压力越大,喷射距离越远,且卫星状血迹逐渐增多,拖尾更拉长;随管径的增加,出现椭圆形血滴所需的压力越高。结论动脉喷溅血迹的形态及喷射距离的观察与测量,可用于推断命案现场喷溅源位置及人体受损伤时的体位。     

命案现场血迹形态分析1例

正命案现场血迹的形态与分布,蕴含着丰富的犯罪行为轨迹信息,通过对命案现场血迹形态与分布机理的分析,可为推断犯罪嫌疑人作案过程的先后次序以及受害人当时所处位置、状态等提供可参考的依据。同时对分析作案时间、作案人数、使用凶器、逃离路线和刻画作案人特征等也具有重要的意义~([1-2])。1案例资料1.1简要案情2009年7月4日夜,某装修店面的两名员工在一辆"本田"商务车轿车内看守店内装潢材料时被杀死     

不同高度滴落血在3种不同载体上的形态和平均直径

暴力犯罪现场一般都会留下各种血迹,如滴落状、喷溅状、流柱状、擦拭状、抛射状血迹等[1,2],能够反映出血迹形成的方式、受害人出血时的位置、出血后的活动情况以及案件发生过程中其它有价值的信息,据此可以重现犯罪现场所发生事件的过程,在甄别证人证言及犯罪嫌疑人供述等方面有非常重要的意义。本文作者将抗凝人血从不同高度垂直滴落在表面光滑程度不等的物体上,对物体上血迹的形态和大小进行测量和观察,旨在找出垂直滴落血迹的特点及形态变化规律,为分析鉴别刑事案件现场的血迹特征提供实验参考资料。1材料与方法将滴管吸满新鲜的抗凝人…     

书讯

<正>《血迹形态分析原理理论与实践》(精装本)斯图尔特H.詹姆斯,保罗E.基什,T伯立特.萨顿著,刘力,唐晖译。本书分别介绍了血迹形态血、血液生物学和物理学特征,血迹分类及形成机理,血迹的现场和实验室检测方法等;讨论了有关血迹分析的法律问题。每个章节都附有案例分析和图片。本书可为犯罪现场勘查、法庭科学实验室检验参考借鉴,也可为法医病理学及相关研究以及相关司法活动所参考。邮寄价格:296元/本。     

垂直抛甩状血迹形态的模拟观察

目的观察不同类型打击工具的垂直抛甩状血迹形态。方法选择常见的菜刀、匕首、方锤、铁管作为打击工具。用沾新鲜鸡血5 m L的工具自上而下进行垂直抛甩,对距离垂直墙壁30 cm处形成的血迹形态进行测量分析,通过对抛甩血迹的整体分布特征(跨度、宽度、密度)、起始血迹的形态特征(长度、宽度、接触角度)进行分析。结果匕首形成抛甩血迹的分布跨度最小(P0.05);在整体分布宽度上,菜刀最小(P0.05);在整体分布密度上,除菜刀与方锤之间差异无统计学意义,其他工具两两之间差异均有统计学意义(P0.05)。方锤较其他三种工具在起始血迹点长度上最长(P0.05);菜刀与方锤、匕首与方锤在起始血迹点宽度上差异有统计学意义(P0.05)。结论每一类型的打击工具所形成的垂直抛甩血迹形态具有一定的特征,可用于命案现场推断打击工具的类型。     

3D 技术在犯罪现场重建中的应用

3D技术在现场血迹重建的应用当前国内对于现场血迹重建的研究重点主要在血迹形态、血迹检测及DNA测定上,由于相关工具的缺乏使对现场血迹的分析应用很难深入和普及。3D技术对现场血迹重建时血迹形态的深入分析提供了很好的工具。目前,3D技术主要应用于现场上因动脉血管破裂,打击、撞击等形成的喷溅状血迹的分析。众所周知,喷溅血迹其形状类似于惊叹号,如果除去其尾部就相当于一个椭圆形。通过实验可知,该椭圆形的形状与血迹投射方向和血迹附着平面的角度(α)有着对应关系,当α为0度时,该椭圆形变为直线;当α为90度时,则为圆形;当α为180度时,则又变为直线。而该椭圆形形状的变化则可以用椭圆形的短轴与长轴之比来表示。根据其变化规律,可推导出其函数关系是α与椭圆的短长轴的比值成正弦函数关系。由此,根据犯罪现场     

9种介质上滴落状血迹的模拟实验研究和应用

目的观察不同高度和速度滴落在9种介质上的血迹的形态、大小及与高度,速度之间的关系。方法采用抗凝人血,在静态和动态条件下,进行滴落状血迹的模拟实验,观察血迹的形态,测量其直径,用spss12.0统计软件进行分析。结果在静态条件下,滴落血迹,多呈圆形,其周围有毛刺状突起;7种介质上滴落血迹的大小(直径)与滴落高度之间有较好的线性关系,可得出回归方程。在慢走、急走、跑、快跑动态条件下,滴落血迹为圆形或椭圆形,沿运动方向的一侧出现突起;高度、速度分别对血迹形态有影响,在水泥路面上两者有交互作用。结论滴落状血迹形态和大小,可用于对出血部位的高度、运动速度和方向的推断。     

“Bubbles”—A Spot Diagnosis

Abstract: Aspiration of blood is a phenomenon observed in violent and natural death scenarios. Bloodstain patterns evolving from expectoration of aspired blood may look suspicious of a violent genesis and thus mislead crime scene investigators. In the present case, a woman was found lying in a pool of blood on the kitchen floor. Furthermore, bloodstains covered her face, clothing, and surrounding furniture and walls. Bloodstain pattern analysis and medicolegal inspection of the suspected scene of crime were carried out and revealed dispersed stains with enclosed gas bubbles in the absence of signs of physical violence leading to the assessment of a natural manner of death. The bloodstains were attributed to expiration of blood because of an internal bleeding. Medicolegal autopsy confirmed the on‐site diagnosis as a fatal esophageal varix rupture was found.     

Changes in the morphology and presumptive chemistry of impact and pooled bloodstain patterns by Lucilia sericata (Meigen) (Diptera: Calliphoridae)

Bloodstain pattern analysis can be critical to accurate crime scene reconstruction. However, bloodstain patterns can be altered in the presence of insects and can confound crime scene reconstruction. To address this problem, we conducted a series of controlled laboratory experiments to investigate the effect of Lucilia sericata (Meigen) on impact bloodstains and pooled bloodstains in association with three combinations of common surfaces (linoleum/painted drywall, wood floor/wallpaper, and carpet/wood paneling). L. sericata fed from the pooled bloodstains and added insect stains through regurgitation and defecation of consumed blood. L. sericata formed defecatory trails of insect stains that indicated directionality. Defecatory stains fluoresced when viewed at 465 nm with an orange filter. These observations differed from Calliphora vicina insect stains because feeding on blood spatter was not observed and trails of insect stains were formed by L. sericata. The fluorescence of defecatory stains can be used as a method to detect insect stains and discriminate them from real bloodstains.     

Alteration of expirated bloodstain patterns by Calliphora vicina and Lucilia sericata (Diptera: Calliphoridae) through ingestion and deposition of artifacts

Abstract: Bloodstain pattern analysis can provide insight into a sequence of events associated with a violent crime. However, bloodstain pattern analysis can be confounded by the feeding activity of blow flies. We conducted two laboratory experiments to investigate the relationships between Lucilia sericata (green bottle fly) and Calliphora vicina (blue bottle fly), expirated bloodstains, and pooled bloodstains on a range of surfaces (linoleum, wallpaper, textured paint). C. vicina and L. sericata changed bloodstain pattern morphology through feeding and defecation. They also deposited artifacts in rooms where blood was not present originally. Chemical presumptive tests (Hemastix^®, phenolphthalein, leucocrystal violet, fluorescein) were not able to differentiate between insect artifacts and bloodstains. Thus, C. vicina and L. sericata can confound bloodstain pattern analysis, crime scene investigation, and reconstruction. Crime scene investigators should be aware of these fundamental behaviors, and the effects that blow flies can have on expirated and pooled bloodstain patterns.     

浅议模拟画像在侦查中的应用

模拟画像是实现对犯罪嫌疑人相貌视觉形象刻画的技术手段。模拟画像应成为犯罪现场勘查工作的一项基本的规范性内容。模拟画像技术要求勘查现场的应解决的主要问题和勘查重点有:(一)寻找、发现目击犯罪嫌疑人的受害人和其他证人;(二)访问、记录目击者对犯罪嫌疑人的感知过程;(三)提取、记录目击者对犯罪嫌疑人体貌特征的记忆;(四)对目击者的调查访问要讲究技巧。模拟画像在侦查中运用应注意的问题:(一)相貌学知识非常重要;(二)必须注意目击者的个体差异对模拟画像的影响;(三)证人之间不要有互相影响的情况;(四)对重要目击者的保护;(五)必要时重新进行模拟画像;(六)划定侦查范围非常重要;(七)可以确定犯罪嫌疑人,不能否定犯罪嫌疑人。     

Detection of latent bloodstains beneath painted surfaces using reflected infrared photography

Bloodstain evidence is a highly valued form of physical evidence commonly found at scenes involving violent crimes. However, painting over bloodstains will often conceal this type of evidence. There is limited research in the scientific literature that describes methods of detecting painted-over bloodstains. This project employed a modified digital single-lens reflex camera to investigate the effectiveness of infrared (IR) photography in detecting latent bloodstain evidence beneath a layer or multiple layers of paint. A qualitative evaluation was completed by comparing images taken of a series of samples using both IR and standard (visible light) photography. Further quantitative image analysis was used to verify the findings. Results from this project indicate that bloodstain evidence can be detected beneath up to six layers of paint using reflected IR; however, the results vary depending on the characteristics of the paint. This technique provides crime scene specialists with a new field method to assist in locating, visualizing, and documenting painted-over bloodstain evidence.     

Quantitative Differentiation of Bloodstain Patterns Resulting from Gunshot and Blunt Force Impacts

Bloodstain pattern analysis (BPA) provides significant evidentiary value in crime scene interpretation and reconstruction. In this work, we develop a quantitative methodology using digital image analysis techniques to differentiate impact bloodstain patterns. The bloodstain patterns were digitally imaged and analyzed using image analysis algorithms. Our analysis of 72 unique bloodstain patterns, comprising more than 490,000 individual droplet stains, indicates that the mean drop size in a gunshot spatter pattern is at most 30% smaller than the mean drop stain size in blunt instrument patterns. In contrast, we demonstrate that the spatial distribution of the droplet stains—their density as a function of position in the pattern—significantly differs between gunshot and blunt instrument patterns, with densities as much as 400% larger for gunshot impacts. Thus, quantitative metrics involving the spatial distribution of droplet stains within a bloodstain pattern can be useful for objective differentiation between blunt instrument and gunshot bloodstain patterns.     

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.     

犯罪现场层次论

犯罪现场层次是犯罪现场存在表现及其被侦查人员认知的程度。犯罪现场是由犯罪时间、犯罪空间、犯罪嫌疑人条件、犯罪痕迹物证、犯罪活动过程、犯罪心理、犯罪证据等各种层次构成的复合体。研究犯罪现场层次论也是研究犯罪现场构成要素的存在及其在不同层面的联系。犯罪现场层次也是研究和揭示犯罪现场存在的一种认知。研究犯罪现场层次问题,也可以使我们对犯罪现场状况及其勘查工作质量给以程度判定。     

Unusual contact marks: connecting the hubcap to the wheel of the car

A case of homicide and attempted homicide is described. The comparison of tire-marks linked the suspect's vehicle to the scene of crime only with low certainty. However, the comparison of the pressure mark on the hubcap found at the scene, with the balance weight on one of the wheels of the suspect's car, connected the suspect to the scene of crime with high certainty.     

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。