骨砍创金属颗粒的检测

目的 应用扫描电镜/X射线能谱仪(SEM/EDX)对菜刀砍击骨质后遗留在创面上的金属微粒进行检测.方法 3种不同材质菜刀各取5把,对猪大腿骨进行砍击,使用SEM/EDX对骨创面上附着的金属颗粒元素以及菜刀自身所含元素进行定性及定量检验,并对结果进行比对分析.结果 菜刀样本同型号之间元素重量百分比相比较,结果无统计学差异(P＞0.05);创面附着金属颗粒与菜刀自身所含元素种类特征相同;其所占重量的百分比一致(P＞0.05);结论 骨骼创面遗留金属颗粒的元素种类及其百分比含量,可以作为区分菜刀类致伤工具的重要依据.     

破坏果树案现场砍切痕迹的应用

果树为多年生木本植物,木质较软,砍切痕迹表面光滑,特征明显而稳定,用斧头、菜刀、砍刀类的刃器工具砍切果树干或技,由于刃器刀面上的豁口、卷刃、小断裂等,沿刀砍方向在工具两侧的枝、干断面形成特征相称或相反的凸凹线条特征.但此类案件中被砍树木往往较多,使前后的痕迹变化较大,且发案至断头的检验有一过程,大量水份被蒸发,断头会枯缩,导致痕迹特征有一定变化.根据作者办案实践总结出应用中有以下几点经验.     

颅骨上工具痕迹检验3例

在农村发生杀人案件中,作案工具的来源是多方面的、多种类的,在所使用的锐器中以砍刀、菜刀、匕首较为常见,是人们日常生活中经常要用的工具,所了同一认定。2分析讨论2·1工具痕迹提取在现场勘验时,对尸体的勘验必须细致。如发现尸体上有被刀砍的痕迹,且在骨骼上形成砍切面,应将该骨骼提取,以备检验。这是进行检验工作的前题条件。2·2检材处理由于骨骼上还附着肌肉组织,需使其与骨骼分离,为此需要对骨骼进行预处理。在对骨骼处理时,刑事技术2006年第1期一般采用水煮沸法较为妥当。若采用滴加硫酸煮沸法,则能缩短预处理时间,但硫酸用量必须…     

毁坏树木案现场砍切痕迹的提取

1 案例 1995年6月,泊头市公安局送来梨树被砍案中现场提取的树干数根;遗留在树干砍切面上的铁片一枚;同时送来嫌疑人的菜刀一把。经检验,铁片是嫌疑人菜刀刀刃上分离下来的,而树干上的砍痕却与菜刀刀刃上的特征有着本质差异。出现上述性质不同的结论,是因为在现场勘查时提取的痕迹是行为人砍切树干开始阶段形成的,而菜刀刀刃上的特征是行为人完成了作案后所留下的。     

充分利用发案前工具的遗留样本进行检验鉴定

1992年2月3日,平泉县郭杖子乡北洞子村于××发现山上果树被砍147棵。现场勘查发现,147棵是同一镰刀所致。侦查发现,本村周××有作案嫌疑。在其家中提取了一把镰刀,此镰刀已新磨,失去了鉴定价值。经了解,1991年秋,周在自己山上砍过柴。为了取到证据,3月10日,在周××家的封山上寻找到一枚1991年9月砍的柞木楂子,与现场痕迹相似。经比对,反映出持械、动作和工具种类的一致性。在体视显微镜下观察,二者纹线起伏状态、表面形状一致。在比对显微镜下对接,粗大、明显、连贯的线条位置、密度均一致,对接吻合,作出同一认定结论(见图)。在确凿的证据面前,周××交待了犯罪事实。     

运用Photoshop软件进行形象痕迹检验

近几年来随着数字图像技术的快速发展,我们在实践中也逐渐将Photoshop运用于刑事科学技术领域的形象痕迹检验,运用电脑设备借助于数码相机或扫描仪,可以在不用显微镜等放大设备的条件下对指纹、足迹、工具痕迹、枪弹痕迹、文件材料进行直接检验,用于痕迹任意倍放大,方向、角度的调整处理,痕迹特征的描述、标注、比对、分析认定,并能直接打印出比对结果。笔者根据自己学习、使用Photoshop进行形象痕迹检验鉴定的实践,现以砍切工具痕迹检验为例将检验方法介绍如下。1检验操作方法根据工具痕迹检验的理论,利用成痕客体表面上反映成痕工具刃口…     

砍切工具痕迹样本制作及检验1例

工具痕迹检验一直是痕迹检验中的难点,一是痕迹样本制作难,二是比对检验难。工具痕迹样本制作的难点一是表现在选用材料上,其硬度、塑性要适当,既要能很好的反映工具的特征,又要不破坏工具的特征;二是要利于操作,能尽量模拟出与现场痕迹形成条件一致的作用方式。因此,合适的材料,对样本的制作会起到事半功倍的效果。比对检验难点表现在痕迹变化多,特征细、密,而比较显微镜视场小,难于定位。笔者在工作中发现“透明皂”是制作砍切工具痕迹样本的一种很好的材料,完全能满足上述二个条件,既经济又容易获得;样本制作完成后利用扫描仪转换成数码照片,与检材照片一同导人Photoshop图像处理软件,就可以直观地进行比对检验。     

国外论文文摘

工具痕迹检验中使用的微量化学斑点测试法[刊,英]/Novoselsky,Y.//法庭科学杂志.-1995,40(5).-865～866 各种切割工具都有可能在犯罪活动中使用,例如:切割锁的钳子和切割电线的剪刀等。为了把从嫌疑犯处搜出的工具与被切割的物证联系在一起,就必须把留在物证上的痕迹与可疑工具产生的痕迹进行对照。在刀片长而留在物证上面的痕迹短的情况下,需要进行多次试切才能找到留在物证上的切痕。当物证材料与工具刀片的钢不同时.为了快速找出工具刀片的切砍区域,用斑点试验法找出留在物证上的可疑工具上的金属痕迹的     

共聚焦显微镜检验工具痕迹的可行性研究

目的验证共聚焦显微镜能否用于工具痕迹检验;方法对实验样本分别用共聚焦显微镜和比对显微镜检测后进行效果比较;结果用共聚焦显微镜检验工具痕迹比用同倍的比较显微镜能发现更多细节特征;结论共聚焦显微镜可以用于工具痕迹检验。     

应用SEM/EDX和ICP-AES检测元素成份判定致伤工具

目的应用扫描电镜/能谱联合分析仪(Scanning electron microscopy & Energy dispersive X-ray apparatus SEM/EDX)和电感耦合原子发射等离子光谱(inductively coupled plasma-atom emission spectrometer ICP-AES)对金属致伤工具本身及所致创口残留物元素成分分析,探讨两者在推断认定此类工具的应用条件及价值.方法镀层和普通铁质工具在乳猪皮肤各致创5例,SEM/EDX对创口内遗留金属颗粒元素检测;用标准样品检测实验方法的精确度;普通铁质工具于刀背、刀刃处各取5个样本,ICP-AES测定元素成分与含量.结果镀锌工具所致创口中存在单一含有锌的金属颗粒,镀黄铜工具则同时含有锌和铜,未发现其它元素;不锈钢或普通铁质菜刀创口中,发现同时含有铁、铬、硅或铁、锰、硅的颗粒;除5号菜刀外同一把铁质菜刀在刀刃、刀背处元素含量无明显差别;ICP-AES分析表明不锈钢菜刀之间在铬、锰、硅、铜、钼和5号刀背部以及其他铁质菜刀在锰、硅元素含量差别具有显著意义,5号刀刃部锰、硅、钼、钛、磷、硫、镍元素RSD明显升高.结论SEM/EDX可以通过创口的检测对金属致伤工具进行种类的推断认定,ICP-AES则可在同种类致伤工具中进行相对同一的判定有应用价值.     

Identifying chop marks on cremated bone: a preliminary study

The purpose of this analysis is to evaluate the effects of burning on hacking trauma inflicted with a cleaver and to assess the diagnostic potential of cleaver marks exposed to fire. Thirty pig forelimbs (radius and ulna) and 30 beef ribs were each subjected to five blows with a cleaver and five cuts with a knife prior to burning in an outdoor fire. Bones were deliberately agitated to ensure maximum cremation and induce fragmentation. Results indicate that hacking weakens bone, making fire-induced fragmentation more likely at the sites of trauma. Chop marks were easily identified on burned bone, their characteristics largely unaffected by cremation.     

Macroscopic characteristics of hacking trauma

Hacking trauma is often encountered in forensic cases, but little experimental research has been conducted that would allow for the recognition of wounds caused by specific weapon types. In this paper, we report the results of a hacking trauma caused by machete, cleaver, and axe weapons and the characteristics of each weapon type on bone. Each weapon type was employed in multiple trials on pig (Sus scrofa) bones and then the wounds were examined macroscopically for several characteristics that serve to differentiate the weapons.     

Chemical trace XRF analysis to detect sharp force trauma in fresh and burned bone

Forensic anthropologists may not always be able to differentiate heat-induced fractures from fractures with other aetiologies, namely sharp force traumas, with clear nefarious impact on medico-legal conclusions. The objective of this study was to experimentally investigate if blade chemical traces are transferred to defleshed bone tissue and if they remain there after a burning event. This was accomplished by prompting sharp force traumas in 20 macerated fresh pig ribs with five different instruments, namely a stainless steel knife, an artisanal knife and a ceramic kitchen knife, a small axe and a large axe. Another pig rib was used as control, not being subjected to any trauma. All instruments were probed by X-ray fluorescence (XRF) to establish the composition of each blade. Bone samples, both pre-burned and post-burned (at 500 °C, 700 °C, 900 °C and 1100 °C), were then probed by XRF. All sharp force instruments left detectable chemical traces on pre-burned bone, although not in all samples. Furthermore, traces were still detected after experimental burning in most cases. Potentially, XRF can provide relevant information about the aetiology of fractures in burned and unburned bones, although the effect of soft tissues and diagenesis must still be investigated.     

Transfer of Triazine‐iron(II) Chromic Complexes Left by Iron Items on Textile Background and Human Skin

Abstract: The research is focused on the detection and transfer of iron traces left by iron items on clothing and human skin. The method is based on the formation of colored complexes between ferrous ions and five synthesized, mostly new triazines. Iron traces originally were left by iron rings on slightly wetted (artificial sweat) cotton fabrics and subsequently transferred to a separate textile substrate. Prior to the use of trazines the contact spots were treated with a new inorganic reducing agent (Sn²⁺) to reduce Fe³⁺ to Fe²⁺. The method is sensitive to detect iron traces on wetted canvas after 10 min contact with iron items. More spectacular results were obtained for traces left on human palm even after very short contact (10 sec). The new iron‐trace‐transfer method eliminated the contact of triazines solutions with human skin. Transmission visible spectra of Fe(II)–triazine complexes were determined.     

Investigation of Ballistic Evidence through an Automatic Image Analysis and Identification System

Automated firearms identification (AFI) systems contribute to shedding light on criminal events by comparison between different pieces of evidence on cartridge cases and bullets and by matching similar ones that were fired from the same firearm. Ballistic evidence can be rapidly analyzed and classified by means of an automatic image analysis and identification system. In addition, it can be used to narrow the range of possible matching evidence. In this study conducted on the cartridges ejected from the examined pistol, three imaging areas, namely the firing pin impression, capsule traces, and the intersection of these traces, were compared automatically using the image analysis and identification system through the correlation ranking method to determine the numeric values that indicate the significance of the similarities. These numerical features that signify the similarities and differences between pistol makes and models can be used in groupings to make a distinction between makes and models of pistols.     

Application of the hexagon-OBTI test and the RSID blood test for the determination of the post-mortem interval of bone samples

In this serial experiment, five human bones with known post-mortem intervals (PMI) in a soil environment from five different epochs (0.2 to approximately 2000 years) were tested in a blind setup with two established rapid tests for the identification of human blood traces (Hexagon-OBTI test and RSID blood test). Based on previous study results concerning the usability of the Luminol test for the first assessment of the PMI of osseous remains, the question arising was whether those test procedures, which are highly sensitive for the detection of human blood components, could also be used to narrow down the post-mortem interval. Five test series were conducted applying modified standard protocols of the manufactures. The aim was to find out whether with prior reaction steps or a prolonged time of incubation hemoglobin or its metabolites can be dissolved from the bone and positive test results can be achieved dependent on the PMI. Four test series yielded negative results for all bone samples and one test series a uniformly weak positive result. The results indicate that rapid tests based on the detection of blood are not suitable for the determination of the PMI of bone samples despite the modification of the standard protocols. Further thorough research is required to clarify the postmortem degradation of hemoglobin in bones.     

Statistical analysis of DNA mixtures using peak area information and allelic drop out

A case of a woman killed in Perugia is reported. The woman was beaten to death and the body showed evidence of bites, kicks and punches. The request of the Court was to verify the presence of bites and if they belonged to humans. Morphological examination and genetic analysis with human Y-specific markers were performed in order to verify the origin of the bites. The DNA profile from the surrounded area of the traces was compared with the profile of the victim's husband (the suspect).The results showed a match between the profile of the suspect and that of the traces for all loci examined. Due to the fact that also other relatives of the husband's male lineage lived in the same house, it was not possible to identify the man who really contributed to the traces. Therefore, the analysis was implemented with autosomal STR markers, which showed a mixed genetic profile. In order to verify the number and the identity of the contributors, statistical analysis based upon peak area information was performed with Probabilistic Expert Systems.     

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。     

A case study on forensic polymer analysis by DIOS-MS: the suspect who gave us the SLIP

New technology was used to identify traces of a commercial barrier/spermicide in evidence from a case of a man accused of rape of a minor. Examination of vaginal swabs performed by another laboratory had been negative for seminal fluid or other sources of DNA from the suspect and we were asked to examine the remaining swabs for any traces that might have originated from the commercial product. Encare consists of vaginal inserts having a suppository-like shape. They contain the spermicide, nonoxynol-9, in a matrix consisting of approximately two parts polyethylene glycol (PEG) 1000 to one part PEG 1450, plus minor inorganic components added to produce foaming. Portions of the cotton from vaginal swabs from the victim and penile swabs from the suspect were extracted with methanol and subsequently examined by desorption ionization on silicon time-of-flight mass spectrometry (DIOS TOF MS). Low levels of PEG in the same mass range as Encare were found on two separate vaginal swabs from the victim and one penile swab from the suspect. Subsequent to these findings, the suspect (through his attorneys) provided us with a sample of SLIP Plus, a commercial sexual lubricant that also contains nonoxynol-9. Traces of PEG in the same mass range as Encare were found in this sample, while no PEG was found in a sealed sample of SLIP Plus provided by the manufacturer. At trial the suspect's attorneys stipulated that their client had added some Encare to the SLIP Plus sample he had provided.     

Out of sight,but not out of mind: Traces of nearby devices' wireless transmissions in volatile memory

An IEEE 802.11 wireless device can leave traces of its presence in the volatile memories of nearby wireless devices. While the devices need to be in radio range of each other for this to happen, they do not need to be connected to the same network—or to any network at all. Traces appear in the form of full wire-type frames; a residue of the signals in the ether. We examine types of information that can be extracted from such residual frames and explore the conditions under which traces develop and persist. Their availability is determined by factors in both in the external environment (the types of signals in the ether) and the internal environment (the configuration and particulars of a device's wifi stack). To isolate some of these factors, we have created memory dumps of devices in various environments and configurations. Analysis of the dumps has offered insights into the conditions determining creation and decay of the traces. The results indicate that they will be available in a limited number of real-world scenarios. We conclude with practical advice on triaging and preservation.