鞋内底浸渍痕迹的检验

1 鞋内底浸渍痕迹的形成 鞋内底浸渍痕迹是指鞋在穿用过程中，由于脚的蹬踩与汗液的浸渍，形成在鞋内底或鞋垫上的印痕。这种印痕与赤足足底具有对应性，在足迹检验中具有较高的利用价值。根据运动力学和生理学的原理，每个人的生理特点和运动能力的差异，形成的运动特征也各不相同，在鞋内底及鞋垫上会形成深浅、虚实不一的赤足形象特征，这就给我们的检验提供了有利的条件。     

利用鞋内穿用特征进行足迹检验

从理论上论述了鞋内穿用特征的形成原理,表现形式及特点,以及鞋内穿用特征的变异性,并利用鞋内穿用特征进行足迹检验的实践.     

鞋内底足迹显现效果的影响因素

目的探究鞋内底足迹的显出情况及可能影响显现效果的因素,寻找有效的鞋内底足迹显现方法。方法收集PU材质的皮鞋鞋垫、EVA材质的运动鞋鞋垫、解放牌胶鞋鞋垫共144只,用多波段光源法、茚二酮法、茚三酮法三种方法分别对穿用时间为一周、一个月、三个月、六个月的鞋内底足迹进行显现,按照显现方法、材质、穿用时间进行分类讨论并对数据进行统计和分析。结果采用多波段光源法、茚二酮法、茚三酮法分别成功显出15、14、19例,有效显出率分别为31.25%、29.17%、39.58%,PU材质、EVA材质、解放牌胶鞋三种材质分别成功显出15、23、10例,有效显出率分别为31.25%、47.92%、20.83%,穿用时间为一周、一个月、三个月、六个月的检材分别成功显出3、6、13、26例,有效显出率分别为8.33%、16.67%、36.11%、72.22%。多波段光源法、茚二酮法、茚三酮法对鞋内底足迹显出率的影响,其差异无明显统计学意义;EVA材质运动鞋鞋内底足迹显出率高于PU材质皮鞋鞋内底足迹显出率,高于解放牌胶鞋鞋内底足迹显出率,并且差异具有统计学意义;穿用时间长的检材显出率高于穿用时间短的检材并且差异具有统计学意义。结论鞋内底足迹的显现效果与鞋内底材质、穿用时间因素有关,多波段光源法、茚二酮法、茚三酮法均能对鞋内底足迹有效显出。     

鞋内底浸渍痕迹在足迹鉴定中应用

鞋内底浸渍痕迹包括通常所说的鞋内底磨损面、鞋垫上的浸渍痕迹等,该痕迹的形成是由于人脚上汗孔排出的汗液在鞋内不易挥发,其中的盐分和其他有机质很容易在鞋内底、鞋垫或皮革及各种合成材料上形成脏污的痕迹,因而鞋一经穿用,脚掌在鞋内固定,穿用人脚的结构形态就通过脚表面的汗液介质在鞋内底或鞋垫上反映出来。这种痕迹在实际工作中同样有较高的利用价值,本文通过一例案件现场上足迹的检验,对鞋内底浸渍痕迹进行了初步探讨,供同行们参考。1案情简介2002年5月10日晚,潜江市某街居民徐某(男,83岁)被人杀死在家中,现场勘查在死者上衣上提取…     

浅谈刑嫌鞋子的整体磨损

在处理足迹方面的检材中,有时需要直接检验与犯罪有关的嫌疑鞋子,以确定被检刑嫌鞋子与现场足迹之间的相关情况。如果把反映人体特性的磨损特征由鞋底扩展到鞋内底、鞋帮,从鞋子的整体磨损特征对人身进行认定,不仅丰富了检验内容,而且检验时依据会更加充分,结论会更加可靠,当现场留有鞋子时更是如此。现就刑嫌鞋子整体磨损特征的识别浅谈如下,供同行参考。 1 鞋子整体磨损的成因及其意义     

足迹检验技术刍议

对不同鞋子(足迹)进行检验鉴定是近2 0多年发展起来的一门具有中国特色的刑事技术手段,先后涌现了步法追踪检验、鞋底磨损特征检验、足迹动力形态检验、单个足迹检验、足迹定量化检验等技术,已达到通过足迹检验直接认定人身的应用阶段。最近几年还将系统分析、计算机自动化检验等加以应用,为足迹检验这门科学的发展提供了高科技平台。其中,因磨损特征检验技术简便易学,可操作性较强,在案件侦破中容易发挥作用,就我市的实际应用情况来看,该项技术在本地区办案部门中普及和认同程度相对较高,基本上是以鞋底磨损特征检验技术应用为主,其他检验…     

谈根据足迹分析行为人的人身特点

足迹是犯罪现场上遗留率最高的一类痕迹,是侦查破案和刑事诉讼中最为常见的重要物证之一。足迹检验技术是同刑事犯罪作斗争的重要手段之一,通过对现场足迹的分析,可以为侦查破案提供线索。本文总结了男女性别各自的足迹一般反映特征,分析了各年龄阶段所反映出来的步幅特征、步法特征和各种体态的人足迹特征的反映,并介绍了几种根据足迹推算年龄、身高的方法。以期能为足迹检验工作提供更加科学的方法和更准确的数据。     

“黄金分割律”在足迹检验中的应用

引用黄金分割律的有关理论与方法,讨论其在足迹检验、特别是残缺足迹检验方面应用的可行性及现实性,具体介绍了足迹各部位特征点与黄金分割律的相关关系,从而达到根据残缺足迹分析完整足迹特征的目的.     

关于足迹边沿特征的检验

在对不同种类足迹的同一检验中,那些反映在足迹边沿上的特征往往容易被忽视,没有把它当作一种特征在检验中加以利用,这是非常可惜的。实践证明,这种反映在足迹边沿上的特征与反映在足迹当中的各种特征一样,它的形成同样与一个人的脚型和行走运动习惯有直接关系,充分认识利用足迹边沿特征,对不同种类足迹进行同一鉴定有着十分重要的意义。     

对足迹检验鉴定理论的思考

我国的足迹检验技术在80年代和90年代得到了较大的发展,足迹检验技术从步法检验、形象检验,发展到鞋底磨损检验、足迹动力形态检验、足迹定量化检验等。特别是近几年,足迹检验中各学派、各门类的各种检验技术内容丰富,方法多样,正在逐步形成具有中国特色的足迹学体系,在侦查破案中发挥了重要作用。目前,常用的足迹鉴定包括:1赤足足迹的鉴定主要以足迹的大小、形象、轮廓、重压部位的密度、乳突花纹、残缺部位、是否变形等特征为赤足足迹进行同一认定,赤足足迹的鉴定又分为平面赤足足迹的鉴定和立体赤足足迹的鉴定。2鞋印足迹的形象鉴定主要…     

A comparison of three shoe sole impression lifting methods at high substrate temperatures

Footwear impressions are a common form of evidence found at crime scenes, and the accurate recovery and recording of such impressions is critical for shoe sole comparison and identification. The lifting of shoe sole impressions from hot surfaces (>30°C/86°F) and in hot environments has received little attention in the literature, particularly in relation to the recovery of class and randomly acquired characteristics (RACs) required for accurate comparisons. This study addressed this knowledge gap by comparing the performance of three common impression lifters (gelatin, adhesive, and vinyl static cling film) at recovering shoe sole impressions in dust from hot flooring substrates. Dry origin dust shoe sole impressions were made on ceramic tile, galvanized metal, and laminated wood flooring using a shoe that possessed two RACs and five class characteristics present on the sole. Substrates were left in direct full sun for five hours during a summer day prior to lifting. Performance was measured by the proportion of RACs and class characteristics visible in each lifted impression. Results demonstrated that the vinyl static cling film tested performed poorly across all substrates, particularly for metal (23.8% marks recovered), including notable shrinkage of the lifted impression. In contrast, adhesive (~96% marks recovered over all substrates), and to a lesser extent gelatin (~85%), lifts were highly successful on hot substrates. These data suggest that adhesive lifts can consistently and accurately recover shoe sole impressions from hot substrates. This study contributes critical information for crime scene examiners to improve and expand evidence recovery in hot environments.     

Barefoot impressions--a preliminary study of identification characteristics and population frequency of their morphological features

Footprint impressions of 107 male adults ranging in age from 19 to 67 years were recorded and examined. Included in this study were foot impressions from a pair of monozygotic twins as well. The impressions were recorded and converted into a set of indices which essentially are width-versus-length ratios of prominent features of the human foot. These indices were then correlated to yield probability values for use in this study and for comparison to data published by previous investigators Qamra, Abbott, Lovejoy, Cassidy, and Robbins. Friction ridge minutae were not considered in this study. Crease marks, well impressions, and toe step measurements were considered, but not incorporated in the probability values, because of the unique aspect of these features and the inability, at present, to convert these features to mathematical indices. These features do, however, introduce a subjective nature to the analysis scheme. This study uses the combined index probabilities of foot impressions so that the data generated can be used to assign a given probability that a particular foot impression, even without clear definable individual features, can be linked to the person who made the impression.     

Controlling the variable of pressure in the production of test footwear impressions

Footwear impression lifting and enhancement techniques may be affected by several variables introduced during the production of test footwear impressions, thus limiting the usefulness of enhancement technique comparisons and the results obtained. One such variable is the force applied when the impressed mark is being made. Producing consistent test impressions for research into footwear enhancement techniques would therefore be beneficial. This study was designed to control pressure in the production of test footwear impressions when mimicking a stamping action. Twenty-seven volunteers were asked to stamp on two different surfaces and the average stamping force was recorded. Information from the data obtained was used to design and build a mechanical device which could be calibrated to consistently deliver footwear impressions with the same force onto a receiving surface. Preliminary experiments using this device and different contaminants on the footwear sole have yielded consistent and repeatable impressions. Controlling the variable of pressure for the production of test impressions in this study demonstrated that the differences observed were visual (due to the amount of contaminant transferred and subsequent enhancement) and did not affect the replication of outer sole characteristics. This paper reports the development of the device and illustrates the quality of the impressions produced.     

Two-dimensional metric comparisons between dynamic bare footprints and insole foot impressions-forensic implications

Footwear may be found at crime scenes as physical evidence. Such footwear often has impression features of the wearer’s foot on the insole of the shoe. Scientific research and literature have established that footprints are distinct. This study compares two-dimensional measurements on bare footprints to foot impressions on insoles to determine if significant differences or similarities exist. Dynamic footprints were collected from 51 donors using the Identicator® Inkless Shoe Print Model LE 25P system. Seven foot length and width measurements were taken based on the Reel linear measurement method. Footprint measurements between bare footprints and foot impressions on the insoles were compared. Only two differences (p > 0.05) were observed between the various bare footprint and insole foot impression measurements on the right and left side for most of the measurements, CALC (p < 0.001) and A1 (p = 0.04). Bare footprint and insole A5 measurements on the left side were also significantly different (p = 0.015). The results of the study have implications in the forensic analysis of foot impression evidence on insoles in footwear in assisting with identifying the wearer of said footwear. Situations may arise in the forensic context when comparing the foot impression on the insole of footwear to a suspect’s bare footprint or a footprint from post-mortem remains. This study contributes to the scant literature available on the topic and to understanding the similarities and differences observed in the various linear measurements that may be utilized in the comparison process of footprint impressions on shoe insoles to bare footprints.     

Uniqueness of bare feet and its use as a possible means of identification

In order to study the uniqueness of barefoot impressions, a computer database has been constructed using inked barefoot prints from volunteers. The data consists of 19 different measurements and a tracing of the impression of each foot. Searches through the present database of 4000 impressions produce an apparent match only if the margin of measurement error is set at an extremely large value. In these few cases, however, a visual examination of the ‘matched’ prints is sufficient to show that they are not the same.     

A Comparison of Various Fixatives for Casting Footwear Impressions in Sand at Crime Scenes

Footwear examination can provide an important link between the crime scene and the suspect. Casts have been taken from snow, soil, and sand substrates to assist with the examination and to accurately depict the impression. However, there has been some discrepancy on what kind of fixative, if any, should be used with impressions present in sand. This study tested four different fixatives on three sandy substrates. Eight gross characteristics were added to a boot sole, and thirty sand impressions were created in each substrate. Except for one control set that remained untreated, the impressions were treated with a fixative agent before casting. The ninety shoe casts were examined by a qualified footwear examiner and scored based on his ability to see the eight characteristics. The results indicated that pump‐action hairspray was the most successful on play and construction sand, while beach sand impressions without any fixative scored highest.     

Manufacturing processes for athletic shoe outsoles and their significance in the examination of footwear impression evidence

The most common methods of manufacturing athletic shoe outsoles are given and how each method can influence the examination of footwear impression evidence. Several processes for manufacturing athletic shoe outsoles are described. Significant factors of each process that are relevant to the examination of footwear impressions are explained. Some manufacturing processes result in distinguishing random characteristics which can assist in the identification of a shoe sole, even when new. These characteristics, together with the traditionally observed wear patterns and random cuts on the shoe outsoles, enable the examiner a stronger basis for expert opinion.     

Collection of Wet‐Origin Footwear Impressions on Various Surfaces Using an Electrostatic Dust Print Lifter

Electrostatic dust print lift method is known to be able to recover only dry‐origin footwear impression. However, the wet‐origin footwear impression could also be recovered using this method. As the amount of dust accumulated before deposition of the wet‐origin footwear impression increased, the intensity of the footwear impression lifted with this method became stronger. If the footwear impression is not affected by moisture after it is made, the 28‐h old wet‐origin footwear impression could be recovered using this method. The intensity of the lifted footwear impression did not decrease significantly even when the number of sequential steps increased as long as the shoe sole is wet. However, when the moisture on the shoe sole depleted, the intensity of the footwear impression decreased sharply. This method has the advantage of being able to enhance the footwear impression without being affected by the footwear impressions deposited in the past.     

Individualizing characteristics of footprints in Gujjars of North India--forensic aspects

Careful examination of foot impressions can provide important evidences and clues in a crime scene investigation. The present study is conducted on a cross-sectional sample of 1040 adult male Gujjars inhabiting the sub-Himalayan region of North India. The study describes the utility of individualizing characteristics of footprints in forensic examinations. Various features of the toes, humps in the toe line, phalange marks, flatfoot condition, pits, cracks, corns, etc., were studied. Frequency of some of these characters has also been recorded. The frequency of the tibialis-type foot is the highest, followed by fibularis-type, then intermediate-type and midularis-type is found to be least frequent among the sample. Three humps have been found most often in footprints, followed by two humps, four humps, and then five humps and one hump are found to be least frequent. Flatfoot condition is found to be present in 1.54% of the sample population and the trait also shows bilateral variation. Phalange marks, crease marks, pits, deformity, etc., are also demonstrated with suitable examples in the present population. These characteristic features can provide useful clues to establish personal identity whenever complete or partial footprints are recovered at the crime scene and can help in including or excluding the possible presence of individual at the scene of crime.     

Operational benefits and challenges of the use of fingerprint statistical models: a field study

Research projects aimed at proposing fingerprint statistical models based on the likelihood ratio framework have shown that low quality finger impressions left on crime scenes may have significant evidential value. These impressions are currently either not recovered, considered to be of no value when first analyzed by fingerprint examiners, or lead to inconclusive results when compared to control prints. There are growing concerns within the fingerprint community that recovering and examining these low quality impressions will result in a significant increase of the workload of fingerprint units and ultimately of the number of backlogged cases. This study was designed to measure the number of impressions currently not recovered or not considered for examination, and to assess the usefulness of these impressions in terms of the number of additional detections that would result from their examination.