物证鉴定的技术方法确认和标准操作规程

物证鉴定中使用的技术方法直接影响和决定了物证检验结果的质量,因此对技术方法的管理是物证鉴定实验室质量保证体系的核心因素之一。开展技术方法的开发确认和内部确认并建立方法的标准操作规程,是保证实验室能够正确选择和使用科学可靠的技术方法,并获得一致结果的主要手段。运行高水平质量保证体系的物证鉴定实验室,应该在案件物证检验工作中使用经过实验室内部确认的技术方法,而且重要新技术方法还应在开发确认基础上进行内部确认,根据方法确认结果建立该方法的标准操作规程。     

2022年度全国司法鉴定能力验证分析报告

<正>能力验证是国际公认的评价和保障实验室/机构能力的有效技术手段。司法鉴定科学研究院（以下简称“司鉴院”）基于其自身职能,自2005年始组织、实施司法鉴定领域的能力验证活动。历经十八年的持续拓展和完善,2022年度的能力验证活动已全面覆盖司法鉴定领域法医类、物证类、声像资料类（以下简称“三大类”）所有鉴定专业,为司法行政管理部门实施行业准入管理、执业分类评审以及行业监管提供了有效的技术支撑,     

物证鉴定实验室的组织和服务体系

世界各国物证鉴定实验室组织结构有多种形式。本文综述了物证鉴定实验室的内部组织、上级组织和服务体系模式 ,分析讨论各种模式的特性和优缺点。物证鉴定实验室组织形式由多种因素决定 ,没有最佳模式     

能力验证和能力测评项目方案论证会在沪举行

2008年5月7日,司法部司法鉴定科学技术研究所主持的本年度能力验证和能力测评项目方案论证会在上海举行,国内27位专家对法医临床、法医病理、文件鉴定、法医毒化和法医物证专业共16个项目方案进行了技术审核。司法部司法鉴定管理局胡占山副局长、何勇处长以及国家认可委能力验证处翟培军处长应邀到会指导并见证了本次活动。     

物证鉴定中的物证污染问题

物证污染是影响物证鉴定结果的最重要因素之一,它会损害物证鉴定结论质量甚至造成错误的鉴定结论。随着以法医DNA检验为代表的物证鉴定技术检验灵敏度的提高,物证污染出现的可能性及其造成的危害程度都显著增加。物证污染有多种形式和来源,可能发生在犯罪现场或实验室。采取适当的污染防范措施可以有效降低物证污染发生的可能性,及时监测和发现物证污染可以将污染造成的危害降到最低。     

我国物证鉴定制度若干问题浅析

物证鉴定在诉讼过程中具有重要作用,但由于其管理制度的不健全和不完善,影响了物证鉴定事业的可持续发展。本文结合我国目前物证鉴定体制现状,对物证鉴定体制的设置模式、运行机制、物证鉴定人的资格认定制度、物证鉴定技术标准和质量控制体系等问题提出了几点建议,以期进一步完善我国物证鉴定制度。     

物证鉴定活动中的几个平衡关系

物证鉴定,与其他各种司法鉴定一样是司法机关委托具有相应鉴定能力的单位和鉴定人进行的与诉讼活动有关的鉴定活动,其鉴定成果有相应的法律效力,是一种法定证据。司法鉴定具有特殊的社会功能,是各种诉讼活动不可缺少的组成部分。物证鉴定活动系指其全部工作环节,包括围绕这些环节开展的实验、调查和评价等工作。从工作程序上看,它包括鉴定的委托、受理、检验和评断等内容;从评断的性质和层次上看,它包括物证鉴定(出具鉴定书)、物证检验(出具检验报告)和技术分析(出具分析意见)等;从对鉴定客体处理的环节上看,它包括样本的采集、送达、实验、传递(当需要做两种或两种以上实验时)、封存、移送(至审判机关)和销毁等。物证鉴定活动是一项庞杂的系统工程,有着独特的内在运行规     

现场勘验阶段物证污染的防控

物证污染是指在犯罪发生后,物证材料在外界因素作用下发生了能够影响物证鉴定结果的性质变化。根据物证污染的阶段可以分为犯罪现场的物证污染和实验室的物证污染,根据物证污染的来源可以分为人的污染、物证之间的相互污染和其他物质的污染,根据物证污染的形态可以分为有形物质污染和无形物质污染,     

全国刑事技术能力验证法医临床学部分试题解析

能力验证（proficiencytesting）,是判定实验室和鉴定机构能力的国际通行方法,同时,可作为实验室内部质量控制的有效补充和外部质量保证。公安部自2006年起举行了4次全国公安系统刑事技术专业实验室法医临床学专业能力验证。本文针对历次验证,从试题设计、答题技巧等方面进行分析,以供同行参考。     

从17025技术要求谈物证照相专业的实验室认可

ISO／IEC17025标准是CNAS对检测和校准实验室能力进行认可的依据。根据国际通行做法,法庭科学实验室认可大多是按照检测实验室标准进行的,如美国FBI、英国FSS等。因此,物证照相专业作为法庭科学实验室的一部分,也应该符合17025标准。深圳市公安局技术处作为全国较早一批整体通过国家实验室认可的单位,笔者参与了物证照相专业实验室认可工作的整个过程,在这个过程中,本人认为ISO／IEC17025标准（即《检测和校准实验室能力认可准则》）技术要求中人员、设备、鉴定方法、检材、环境条件这5个方面不仅关系到能否顺利通过CNAS对实验室的评审,而且直接决定了实验室的检测水平,     

Proficiency Testing as a Basis for Estimating Uncertainty of Measurement: Application to Forensic Alcohol and Toxicology Quantitations

Abstract: While forensic laboratories will soon be required to estimate uncertainties of measurement for those quantitations reported to the end users of the information, the procedures for estimating this have been little discussed in the forensic literature. This article illustrates how proficiency test results provide the basis for estimating uncertainties in three instances: (i) For breath alcohol analyzers the interlaboratory precision is taken as a direct measure of uncertainty. This approach applies when the number of proficiency tests is small. (ii) For blood alcohol, the uncertainty is calculated from the differences between the laboratory’s proficiency testing results and the mean quantitations determined by the participants; this approach applies when the laboratory has participated in a large number of tests. (iii) For toxicology, either of these approaches is useful for estimating comparability between laboratories, but not for estimating absolute accuracy. It is seen that data from proficiency tests enable estimates of uncertainty that are empirical, simple, thorough, and applicable to a wide range of concentrations.     

The feasibility of external blind DNA proficiency testing. II. Experience with actual blind tests

The background and goals of a national study to determine the feasibility of blind proficiency testing in U.S. forensic DNA laboratories are discussed. Part of the project involved designing and executing a series of fifteen blind proficiency tests. Execution included biological specimen donor recruitment and case evidence manufacturing. Simulated cases were submitted to DNA laboratories by law enforcement agencies and in some cases by other forensic-science laboratories. Replicate-manufactured evidence was submitted to reference laboratories to simulate the workings of a larger-scale program. Ten tests were straightforward, and essentially tested analytical ability. Five tests involved selecting on the basis of case facts appropriate bloodstains for typing from a bloodstain pattern. We describe in detail our experience in designing and conducting these blind proficiency test trials, and relate those experiences to the overall issue of blind proficiency testing as a quality-assurance tool in forensic DNA laboratories. In this feasibility test series, one blind test was detected by a laboratory, a second one was shown to the lab by law enforcement, and a third was never completed because of lapses in communication. Turnaround times were relatively fast in the independent/commercial labs and relatively slow in the larger public laboratories. Two cross-state case-to-case CODIS "hits" were "planted" among the first series of ten blind tests. One pair was detected. One member of the second pair went to a lab that was not CODIS-ready.     

How do latent print examiners perceive proficiency testing? An analysis of examiner perceptions,performance, and print quality

Proficiency testing has the potential to serve several important purposes for crime laboratories and forensic science disciplines. Scholars and other stakeholders, however, have criticized standard proficiency testing procedures since their implementation in laboratories across the United States. Specifically, many experts label current proficiency tests as non-representative of actual casework, at least in part because they are not sufficiently challenging (e.g., [1], [2], [3], [4]. In the current study, we surveyed latent print examiners (n = 322) after they completed a Collaborative Testing Services proficiency test about their perceptions of test items. We also evaluated respondents’ test performance and used a quality metric algorithm (LQMetrics) to obtain objective indicators of print quality on the test. Results were generally consistent with experts’ concerns about proficiency testing. The low observed error rate, examiner perceptions of relative ease, and high objective print quality metrics together suggest that latent print proficiency testing is not especially challenging. Further, examiners indicated that the test items that most closely resembled real-world casework were also the most difficult and contained prints of the lowest quality. Study findings suggest that including prints of lower quality may increase both the difficulty and representativeness of proficiency testing in latent print examination.     

Perceptions of blind proficiency testing among latent print examiners

In recent years, scholars have levied multiple criticisms against traditional proficiency testing procedures in forensic laboratories. Consequently, on several occasions, authorities have formally recommended that laboratories implement blind proficiency testing procedures. Implementation has been slow, but laboratory management has increasingly expressed interest in initiating blind testing in at least some forensic disciplines, with some laboratories conducting blind testing in almost all disciplines. However, little is known about how a key population perceives blind proficiency testing, i.e., forensic examiners. We surveyed active latent print examiners (N = 338) to explore perceptions of blind proficiency testing and determine whether beliefs varied between examiners who work for laboratories with and without blind proficiency testing. Results suggest that examiners do not hold particularly strong beliefs about such procedures, but that examiners who work in laboratories with blind proficiency testing procedures view them significantly more positively than those who do not. Further, examiner responses provide insight into potential obstacles to continued implementation.     

Implementation of a Blind Quality Control Program in a Forensic Laboratory

A blind quality control (QC) program was successfully developed and implemented in the Toxicology, Seized Drugs, Firearms, Latent Prints (Processing and Comparison), Forensic Biology, and Multimedia (Digital and Audio/Video) sections at the Houston Forensic Science Center (HFSC). The program was put into practice based on recommendations set forth in the 2009 National Academy of Sciences report and is conducted in addition to accreditation required annual proficiency tests. The blind QC program allows HFSC to test its entire quality management system and provides a real-time assessment of the laboratory’s proficiency. To ensure the blind QC cases mimicked real casework, the workflow for each forensic discipline and their evidence submission processes were assessed prior to implementation. Samples are created and submitted by the HFSC Quality Division to whom the expected answer is known. Results from 2015 to 2018 show that of the 973 blind samples submitted, 901 were completed, and only 51 were discovered by analysts as being blind QC cases. Implementation data suggests that this type of program can be employed at other forensic laboratories.     

The feasibility of external blind DNA proficiency testing. I. Background and findings

We describe the origins, purposes, and findings of a national study to determine whether a large-scale program of blind proficiency testing in U.S. DNA laboratories is feasible and/or practical. Proficiency testing in clinical laboratories is reviewed, particularly as mandated by the Clinical Laboratory Improvement Acts and its role in the regulation of those laboratories. Proficiency testing in forensic urine drug testing labs is also briefly reviewed. Studies involving comparisons between open and blind proficiency testing are discussed. The clinical laboratory proficiency testing and regulation landscape provides the background for the DNA Act of 1994, and the congressional mandate to investigate blind proficiency testing in forensic DNA laboratories. Four models of blind proficiency testing are defined and discussed, along with the advantages and disadvantages of each and estimates of the costs of a large-scale program. The purposes of proficiency testing in a quality-assurance context are likewise discussed and related to the models and the arguments generally proffered for and against blind vs. open proficiency testing.     

The current status of forensic science laboratory accreditation in Europe

Forensic science is gaining some solid ground in the area of effective crime prevention, especially in the areas where more sophisticated use of available technology is prevalent. All it takes is high-level cooperation among nations that can help them deal with criminality that adopts a cross-border nature more and more. It is apparent that cooperation will not be enough on its own and this development will require a network of qualified forensic laboratories spread over Europe. It is argued in this paper that forensic science laboratories play an important role in the fight against crime. Another, complimentary argument is that forensic science laboratories need to be better involved in the fight against crime. For this to be achieved, a good level of cooperation should be established and maintained. It is also noted that harmonization is required for such cooperation and seeking accreditation according to an internationally acceptable standard, such as ISO/IEC 17025, will eventually bring harmonization as an end result. Because, ISO/IEC 17025 as an international standard, has been a tool that helps forensic science laboratories in the current trend towards accreditation that can be observed not only in Europe, but also in the rest of the world of forensic science. In the introduction part, ISO/IEC 17025 states that "the acceptance of testing and calibration results between countries should be facilitated if laboratories comply with this international standard and if they obtain accreditation from bodies which have entered into mutual recognition agreements with equivalent bodies in other countries using this international standard." Furthermore, it is emphasized that the use of this international standard will assist in the harmonization of standards and procedures. The background of forensic science cooperation in Europe will be explained by using an existing European forensic science network, i.e. ENFSI, in order to understand the current status of forensic science in Europe better. The Council of Europe and the European Union approaches to forensic science will also be discussed by looking at the legal instruments and documents published by these two European organizations. Data collected from 52 European forensic science laboratories will be examined and findings will be evaluated from a quality assurance and accreditation point of view. The need for harmonization and accreditation in forensic science will be emphasized. The steps that should be taken at the European level for increasing and strengthening the role of European forensic science laboratories in the fight against crime will be given as recommendations in the conclusion.     

Development and Implementation of an Effective Blind Proficiency Testing Program

Blind proficiency testing is ideal for testing crime laboratory personnel because the elements of analyst bias and anticipation are removed. However, sending proficiency tests through the laboratory system as real casework is difficult. The substantial challenges with preparing and administering blind tests may prevent laboratory managers from initiating blind testing. In 2015, the Harris County Institute of Forensic Sciences committed to improving its crime laboratory’s proficiency testing program by adding blind tests. The goal was to test the whole system, from evidence receipt to report release. With careful planning, trial-and-error, and ongoing assessment of available resources, not only was the program proven to be feasible, but there was also clear understanding of how to optimize our program. In this article, we share our experiences, lessons learned, and program details to assist other forensic service providers with developing their own blind testing programs, which would ultimately lead to improved quality assurance.     

Preparation and application of a fortified hair reference material for the determination of methamphetamine and amphetamine

Quality assurance is one of the major issues in forensic analytical laboratories, where the need for a reference material (RM) has rapidly increased. RMs are very useful for method development and validation, internal quality control or proficiency tests. In the present study, we prepared a RM using drug-free hair for the determination of methamphetamine (MA) and its main metabolite, amphetamine (AP) according to the recommendations of ISO Guide 35. The concentrations of MA and AP were determined using two extraction methods, agitation with 1% HCl in methanol at 38 degrees C and ultrasonication with methanol/5M HCl (20:1), followed by gas chromatography/mass spectrometry (GC/MS) after derivatization with trifluoroacetic anhydride (TFAA). The assignment of values was conducted through the homogeneity study and characterization of the material. Furthermore, an internal proficiency test was performed with the prepared RM, of which the results were compared with those of the authentic hair RM prepared in our previous study. As a result, a hair RM containing MA and AP was prepared at the level of 4.86+/-0.69 ng/mg and 4.63+/-0.44 ng/mg, respectively. Most participants showed satisfactory performances in the internal proficiency test with the both RMs. The hair RM prepared in this study demonstrated its suitability for quality assurance in forensic laboratories.