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目的统计分析1574例盗窃案件中提取的2496个现场生物检材,为提高DNA在盗窃案件侦破中的应用成效提供参考。方法根据2496个生物检材的类型、现场提取方法、重点提取部位、DNA检测结果等进行统计和分析比较,总结常见类型盗窃案件现场生物检材的主要发现提取部位以及不同方法提取的现场生物检材DNA检出率。结果接触类检材已成为盗窃案件最多见的生物检材类型,但检出率仍然较低,对混合分型应进一步分析筛选以提高DNA的认定率;不同方法提取的现场生物检材在DNA检出率方面存在统计学差异,接触类生物检材以植绒拭子和原物提取的方式为首选;现场生物检材的主要发现提取部位根据盗窃案件的类型不同有所侧重。结论现场勘查人员在盗窃案件中发现和提取到有价值的生物检材是提高DNA检出认定能力的关键因素,应着力培养现场勘查人员的微量生物物证意识,提高现场勘查人员提取和处理微量生物检材的能力。 相似文献
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本文阐述了公安侦查人员在各种刑事案件的现场勘察和检验过程中,应如何发现和提取案件现场中的生物检材。 相似文献
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目的分析188份接触DNA检材的提取、送检和检验结果,探讨接触DNA检出率及可能影响接触DNA检验的因素。方法收集本辖区2016年1月至2016年10月提取并送检的188份接触DNA检材,按照检材载体性质、提取方法、送检时间、检出率等进行分类,采用SPSS13.0软件对数据进行统计分析和χ2检验。结果188份接触DNA检材成功进行STR分型的有38份,检出率为20.21%;其中表面质软、粗糙的载体接触DNA检出率58.82%,高于其它载体接触DNA检出率组的差异具有统计学意义;直接原物提取的接触DNA检材检出率42.11%,高于脱落细胞粘取器提取、棉签拭子转移提取的检出率组的差异具有统计学意义;送检时间早的检材检出率高于送检时间晚的检材组且具有统计学意义。结论接触DNA检材的检出率受载体性质、提取方法、送检时间等因素影响,日常现场勘查时要注重发现检出率高的载体上的接触DNA选择适当的方法提取,并及时送检。 相似文献
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随着DNA提取和检验技术的进步与不断发展,犯罪现场遗留的DNA对于刑事犯罪侦查中犯罪嫌疑人的确定有着举足轻重的作用,但同时犯罪嫌疑人的反侦察意识越来越强,在作案过程中以及实施犯罪行为后遗留在现场的物证微乎其微。因此在对现场物证进行采集的过程中,接触性生物物证的发现、提取和DNA检出越来越重要。目前在犯罪现场中接触性检材所占的比例越来越大,对于案件的侦破也发挥着越来越大的作用。然而这些接触性检材一般极其微量、体积小、较为隐蔽、肉眼不易观察,且现场的各种污染大大加快了这种微量检材的降解速率,因此对于这类检材的检验和分析就成了法医物证检验工作的重点和难点。本文综述了接触DNA的种类、采集和提取方法,影响其检出的因素以及检验中遇到的问题,以期能更好地将其运用到法医学鉴定实践中。 相似文献
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Mark Barash M.Sc. Ayeleth Reshef M.Sc. Paul Brauner M.Sc. F.F.S.Soc. 《Journal of forensic sciences》2010,55(4):1058-1064
Abstract: The selection of the appropriate method of collection of biological material from crime scene items can be crucial to obtaining a DNA profile. The three techniques commonly used for sampling items are: cutting, swabbing, and taping. The tape sampling technique offers an advantage, in that it enables the collection of a potentially highly informative source of DNA, shed epithelial cells, from selected areas on crime scene items (the inside fingers of a glove, for instance). Furthermore, surface collection of biological material by taping reduces co‐sampling of known PCR inhibitors such as clothing dyes. The correct choice of tape for crime scene item sampling is important. Not all tapes are suitable for biological trace evidence collection as well as DNA extraction. We report on one tape that met both these criteria. Three different cases are presented which demonstrate the usefulness of adhesive tape sampling of crime items. Finally, the advantages of the tape collection technique are discussed and guidelines for preferred areas of tape sampling on various casework items are presented. 相似文献
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A method for determining the age of a bloodstain 总被引:2,自引:0,他引:2
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《Forensic Science International: Genetics Supplement Series》2013,4(1):e51-e52
Allelic drop-out continues to be a challenge to forensic geneticists when interpreting crime scene evidence and calculating the evidential weight. Methods exist for estimating the probability of allelic drop-out, where the most promising methods use the signal intensities as input for quantifying the drop-out probability. Using data from real crime cases, we demonstrate that taking degradation of the biological material and truncation of the data due to a detection threshold into account is superior to previous approaches. An additional correction for stuttering effects showed limited improvement. 相似文献
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玻璃碎片及形态是案发现场常见的物证形式,开展对玻璃的物证分析研究,能够确定玻璃的来源与种类,推断玻璃破碎原因等,为案件的取证、重建和侦破提供线索和证据。简要介绍了常见玻璃的种类,分析了玻璃破碎的根本原因,总结了低速冲击和高速冲击下玻璃破碎的形态特征,还从玻璃碎片收集和检验两个方面探讨了玻璃实体物证的分析。 相似文献
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剥离重叠的犯罪行为与其他行为的侦查价值 总被引:1,自引:0,他引:1
立足犯罪现场,历来是侦查人员认识和分析犯罪现场的根本。但犯罪现场是一个非常复杂的社会现象及社会行为的存储场所及空间。侦查人员应用不同的认识及方法,力从犯罪现场发现与犯罪有关的线索及证据,这是其最重要的任务。但犯罪现场的复杂性是难以预料的。有的现场既存有犯罪行为,也还遗留着其他与犯罪行为有关的其他行为,即本文所述的非犯罪行为。将犯罪行为与非犯罪行为剥离,从中发现证实犯罪有关的证物及线索,是新的侦查思路。 相似文献
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《Science & justice》2022,62(2):152-155
Successful DNA typing of forensically relevant evidence is reliant on both the quality and quantity of biological material recovered from a crime scene. In geographical areas of the world exposed to cold climates, it is not uncommon for biological evidence to encounter a diversity of challenging surfaces and environments, including snowy surfaces. Currently, there is no standard protocol for recovery of bloodstain evidence in snow and very few publications exploring adequate methods of recovering biological evidence from snowy surfaces. In this study, three common substrates (e.g., cotton swabs, FTA paper, and untreated filter paper) utilized by investigators for evidence recovery were evaluated for their ability to recover human blood (DNA) evidence from snow that would be viable for traditional forensic DNA typing. Each biological sample was extracted and quantified to evaluate the quality and quantity of DNA recovered. All samples yielded sufficient non-degraded DNA to proceed with DNA profiling, where complete DNA profiles were generated from each collection substrate. The experimental findings presented herein demonstrate that the ability to recover viable DNA from human blood collected on surface snow is possible using all three collection methods tested. 相似文献
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Sheng Lin M.S. Yaping Luo Ph.D. Lianqun Xie B.S. Yang Yu Ph.D. Zhongliang Mi B.S. 《Journal of forensic sciences》2019,64(6):1913-1915
We present a case of a faux blood fingermark, wherein a natural latent fingerprint on the pistol at the crime scene was enhanced by the whole blood of the victim. A male was shot to death. The crime scene investigator did not find any blood fingermark during the collection of evidence, but a blood fingerprint was noticed in the firearms examination. We identified that the fingerprint was of the victim; a series of experiments on the nonporous substrate were then conducted; the death in this case was classified as a suicide. The phenomenon is interesting, and thus, calls for attention of the forensic community. 相似文献
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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. 相似文献