Passport examination by polarized infrared spectra

In this study, a new nondestructive technique for passport examination is proposed. In this technique, linearly polarized light is used to measure Fourier transform infrared (FT-IR) reflectance spectra of films on the biographical data page. Thirty genuine and thirty-five counterfeit Japanese passports and five marketed films pasted on name cards were examined. The measured spectra were analyzed as follows. The absorption spectra were obtained by the Kramers-Kronig transformations of reflectance spectra. The peak ratios were then calculated from the absorption spectra by adding the peak areas at 1126 and 1263 cm(-1) and dividing the result by the peak area at 1727 cm(-1). When nonpolarized light was used, the samples could not be distinguished by comparing the peak ratios. However, when polarized light was used, they were successfully distinguished by the comparison. Therefore, polarized light is useful for the forensic discrimination of passport films by the measurement of FT-IR spectra.     

The potential of collaborative learning as a tool for forensic students: Application to signature examination

Transferring theoretical knowledge to practical skills remains a big challenge in forensic science, especially in questioned documents. The examination of handwriting and signatures requires years of practice to develop the necessary skills. While students (and to some extent the general population) often have the impression that it is easy to differentiate handwriting from different persons, in practice, particularly when dealing with simulated signatures, there is a high risk of reaching a wrong conclusion when questioned document experts do not use a systematic approach and/or are not sufficiently experienced (see for example the famous French Dreyfus case). Thus, a novel teaching approach, based on collaborative learning, has been introduced in a theoretical handwriting class to improve the students’ theoretical knowledge, and additionally make them aware of the limitations of their practical skills and give them tools to improve them in their future practice. Through five activities, the students took the roles of victims, forgers, teachers and experts and created their own learning materials (i.e. signatures and mock casework). During those interactive activities, they learned to describe their signature’s characteristics, intra-variability and complexity, and thus evaluate their own signature’s vulnerability (as potential victims). They learned techniques to simulate signatures and detect the resulting forgeries’ characteristics (in the role of forgers). In the role of teachers, they prepared mock casework scenarios and gave feedback to their colleague’s examination of the produced material. As experts, they carried out signature examination as they would in a proficiency test and were exposed to the difficulties an actual expert may encounter in practice. The evaluation of this novel teaching scenario was very positive, as students learned more extensively the possibilities and limitations of signature comparison. They were more active and motivated in their learning experiences. The teaching team also had an improved experience. Some students complained of an increased workload and imprecise instructions. Improvements were tested and are discussed in this paper.     

Investigating the effect photodegradation has on natural fibres at a microscopic level

It is a known fact that when fabric is left exposed to sunlight photodegradation occurs. However, no study has ever looked at the photodegradation that occurs to individual fibre filaments as commonly recovered from a scene of crime. To look at photodegradation of individual fibres, wool and cotton fabric were dyed using CI Acid Red 27 and CI Direct Red 80 respectively at two depths of shade, 0.25% and 2.0% owf. Pieces of fabric and individual fibre samples were then placed in a Light Fastness Q-Sun 1000 Xenon test chamber which simulated exposure to sunlight over two time periods, 64 h (equivalent to one weeks sun exposure) and 128 hrs (equivalent to two weeks sun exposure). The resulting pieces of fabric and fibres where then examined using high power comparison microscopy, as well as graded for colour fading using SDC Grey Scale for Assessing Change in Colour (including half steps). Results show that in both fibre types, photodegradation occurs in all samples, however, the degree of fading is shown to vary within a given fibre population showing it is unpredictable in nature.     

专家辅助人出庭质证规则研究

现代科学技术的迅猛发展对司法审判产生了巨大的影响,各种科学问题、技术证据、鉴定意见呈现于法庭,法官在审判案件中由于知识和经验的局限性而难以判断,在此背景下专家辅助人制度应运而生。英美法系有专家证人制度,存在完善的以交叉询问为主的专家证人出庭质证规则,大陆法系国家和地区有诉讼辅助人制度,虽然立法中没有明确的出庭质证规则,但是有完善的鉴定人出庭质证规则。我国当前专家辅助人出庭质证规则没有明确的规定,但准用证人出庭质证规则。不过目前缺乏进一步的理论阐述,且简单直接适用也存在问题,同时缺乏系统的、具体的、具有可操作性的质证规则。对此笔者提出构建专家辅助人出庭质证规则的建议。     

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。     

Not guilty by reason of insanity: clinical and judicial profile of medium and high security patients in Belgium

Under Belgian law, offenders deemed to lack criminal responsibility because of insanity receive mandated treatment under the internment law. Population profiles of these forensic patients (‘internees’) are, however, very scarce. In this study, we analysed the demographic, clinical and judicial profile of a large sample of Belgian internees admitted to a secure setting. In addition, differences between internees admitted to a medium versus a high security setting were investigated. Belgian internees were characterised by a large number of personality disorders and a low number of first offenders. Comparative analyses showed substantial differences between the high and medium security settings, with a marked proportion of the forensic patients in high security having committed a sexual offence. Contrary to expectations, more predictors for length of stay were found in the medium security subsample, while admission periods were significantly longer in the high security subsample.     

Identification of colorants in pigmented pen inks by laser desorption mass spectrometry

Pigments are rapidly replacing dyes as colorants in pen and printer inks, due to their superior colors and stability. Unfortunately, tools commonly used in questioned document examination for analyzing pen inks, such as TLC, cannot be used for the analysis of insoluble pigments on paper. Laser desorption mass spectrometry is demonstrated here as a tool for analyzing pigment-based pen inks. A pulsed nitrogen laser can be focused onto a pen stroke from a pigmented ink pen on paper, and positive and negative ions representative of the pigment can be generated for subsequent mass spectrometric analysis. Targeted pens for this work were a set of Uni-ball 207 pigmented ink pens containing blue, light blue, orange, green, violet, red, pink, and black inks. Copper phthalocyanine was identified as the pigment used to make both blue inks. A mixture of halogenated copper phthalocyanines were identified in the green ink. Unexpectedly, the pink ink was found to contain a red pigment, Pigment Red 12, treated with a mixture of water-soluble dyes. Each sample yielded ions representative of the pigments present.     

Violence risk profile of medium- and high-security NGRI offenders in Belgium

Under Belgian law, offenders not guilty by reason of insanity (NGRI) are committed by the courts to forensic mental health treatment. The use of violence risk assessment tools has become routine in these settings. However, there are no national statistics regarding violence risk assessment in the Belgian forensic population. A study was undertaken to collect risk assessment data (PCL-R, VRAG, HCR-20) on a large cohort of forensic patients committed to Medium Security units in the Flanders region and in High-Security units in the Walloon region. Flemish patients were expected to present a lower risk compared with their Walloon counterparts. Instead, data yielded by a structured risk assessment method demonstrate the opposite. Moreover, the majority of patients in Flemish facilities had committed violent offenses and were institutionalized for shorter periods whereas the majority of Walloon patients had committed sexual offenses and were institutionalized for markedly longer periods.     

法医学尸体检验职业防护指南(建议稿)

法医工作者的职业暴露风险极大,案件现场及尸体上的有毒有害物质、高致病性微生物以及利器、骨折等因素均可能给法医带来身心伤害甚至生命危险。随着经济社会发展,法医的工作环境已经较过去显著改善,但是针对个人防护的重视程度仍需提高。近年来公共卫生事件频发,给法医职业防护带来新的挑战,迫切需要借鉴生物安全领域的先进技术和防护理念,以满足新形势下法医工作的需要。本指南立足当前法医职业防护的实际需求,从暴露风险、防护分级、应急处置等角度阐述,希望能为制定法医职业防护相关标准提供参考,以指导法医工作者开展个人防护工作,为提升法医职业化水平和身心健康提供帮助。     

扫描电镜/能谱观察溺死和死后入水的法医学应用研究

目的探讨扫描电镜/能谱分析在溺死的法医学鉴定中的作用。方法实验选用20例已知生前入水尸体,11例已知的死后入水尸体和2例陆地死亡尸体。在每个肺叶各取3个切面,每个切面用扫描电镜取样台胶面与肺叶的切面充分接触,另在落水地点取水样一份,进行对比。扫描电镜取样台胶在切面上充分接触后封闭取材盒,真空干燥后,直接在扫描电镜下进行观察。结果20例生前入水尸体在肺组织中均检出异物颗粒,并且与对照水样中检出的异物颗粒相吻合;而死后入水的尸体和在陆地上死亡的尸体肺组织中均未检出明显的异物颗粒,3者比较P<0.0001。在肺组织支气管切面中,生前入水的20例中有15例检出异物颗粒,在边缘肺切面及中间切面中分别有13例检出异物颗粒,统计学无明显差异。结论本实验建立的肺脏内异物颗粒取材方法准确可靠实用。对综合判断案件的性质,判断溺死尸体入水地点的具有积极意义。较好地解决了实验室检验中的污染问题。腐败尸体对检测结果无影响。     

Determination of the Sequence of Intersecting Lines Between Toners and Seals by Laser Fluorescence Microscope

Fluorescence microscope is considered to be one of the most effective ways to examine the sequence of intersecting seal and toner lines of questioned documents. In reality, however, the toner (mainly divided into compact and noncompact toners) and seal of a questioned document have such a complex morphology and sequence of crossing lines that current methods cannot meet the requirement of practical document identification. In view of the challenges of document examination, a laser fluorescence microscope and method are developed in this study. The developed microscope provides additional functionality to traditional fluorescence microscopes of transmitted light modality, laser excitation, selectable excitation wavelength, and selectable fluorescence filters. The results obtained from the method of comparisons between transmitted light and fluorescence modalities were positive under most conditions, particularly for noncompact toner examination for which a 100% accuracy rate and 90% detection rate were achieved in blind testing.     

FAM羧基荧光素修饰引物检测D1S80基因座遗传多态性

目的建立用FAM羧基荧光素修饰引物检测DIS80基因座的方法。方法采用5-FAM修饰引物,通过PCR扩增,DNA全自动遗传分析仪进行片段长度分析,检测129名黑龙江汉族无关个体DIS80基因座遗传多态性。结果在所调查的129名黑龙江汉族无关个体样本中,DIS80基因座有21个等位基因,56个基因型,基因频率在0.0039-0.1667之间。杂合度(H)为0.9097,个人识别机率(PD)为0.9691,非父排除概率(PE)为0.8113,多态性信息总量(PIC)为0.8988。群体内基因型频率分布符合Hardy-Weinberg平衡。结论FAM羧基荧光素修饰引物检测DIS80基因座的方法,简便、灵敏、稳定性好,DIS80基因座用于个体识别及亲权鉴定具有很高的实用价值。     

利用暗记特征鉴别彩色激光打印、复印文件

目的探讨激光打印机的暗记特征,为鉴别彩色激光打印、复印文件找到一种有效的方法。方法根据不同物质对光的反射特性及蓝色与黄色互补特性的原理,采用420nm左右蓝光照射方法,对部分品牌彩色激光打印、复印文件进行了初步分析研究,总结了暗记点阵形态特征、小点形态特征、出现位置特征和排列含义等特征。结果此方法对彩色激光打印、复印机具的种类鉴别和个体鉴别简便、有效。     

文件鉴定人员质量控制内容比较及启示

文件鉴定作为一项重要的司法鉴定活动,其鉴定意见作为证据被广泛地应用在诉讼阶段,同时,文件鉴定意见作为证据使用的风险也不容忽视。为了提供高质量的鉴定意见,文件鉴定专业的质量控制就显得尤为重要。特别是其学科较大地依赖于文件鉴定人的技术、经验、能力等背景,质量控制更应该侧重于对从业人员的质量管理。本文在调研国内外关于文件鉴定质量控制相关标准规范的基础上,在从业人员的资格审查、培训制度、考核制度等方面进行对比分析,从中发掘有益的启示,旨在为我国文件鉴定从业人员质量控制的建设和发展提供借鉴。     

法庭科学痕迹检验实验室质量控制的现状及进展

痕迹检验实验室作为法庭科学实验室的重要组成部分,其质量控制活动在遵循普遍原则的基础上,根据自身专业特性,在质量控制方法选择及活动实施上有所侧重.本文在调研国内外关于痕迹检验实验室质量控制研究与实践的基础上,从结果质量控制、人员资格和培训、方法确认、记录、结果报告、出庭等方面对痕迹检验实验室质量控制要求及现状进行综述,旨在探索痕迹检验实验室的质量控制关键技术,尽快建立国内痕迹检验实验室质量控制规范.     

The probative character of Forensic Handwriting Examiners’ identification and elimination opinions on questioned signatures

This 5-year study investigated the character of Forensic Handwriting Examiners’ (FHEs) authorship opinions on questioned signatures through the medium of blind validation trials. Twenty-nine thousand eight hundred and eleven authorship opinions were expressed by FHEs on trial kits comprising randomized questioned genuine signatures (written by the specimen writer), disguised signatures (written by the specimen writer) and simulated signatures (not written by the specimen writer). Results showed that, as a group, FHEs were significantly more confident at identifying writers’ genuine signatures than identifying writers’ disguised signatures or eliminating specimen writers from having authored simulated signatures. It is proposed that the difference in FHE confidence arises from the difficulty they have in deciding which alternative authorship explanation accounts for perceived combinations of similar and dissimilar features between specimen and questioned signatures.     

The probative character of Forensic Handwriting Examiners' identification and elimination opinions on questioned signatures

This 5-year study investigated the character of Forensic Handwriting Examiners' (FHEs) authorship opinions on questioned signatures through the medium of blind validation trials. Twenty-nine thousand eight hundred and eleven authorship opinions were expressed by FHEs on trial kits comprising randomized questioned genuine signatures (written by the specimen writer), disguised signatures (written by the specimen writer) and simulated signatures (not written by the specimen writer). Results showed that, as a group, FHEs were significantly more confident at identifying writers' genuine signatures than identifying writers' disguised signatures or eliminating specimen writers from having authored simulated signatures. It is proposed that the difference in FHE confidence arises from the difficulty they have in deciding which alternative authorship explanation accounts for perceived combinations of similar and dissimilar features between specimen and questioned signatures.     

Use of hand-held laser scanning in the assessment of craniometry

The intra- and inter-examiner reliability was evaluated for hand-held 3D laser scanning technology when it was combined with localization of landmarks for craniometry. The data from the laser surface scanning were compared with those of conventional direct measuring. Using thirty unidentified skulls requested for individual identification, measurements were taken of the line distances from lambda to 26 landmarks, and also for seven breadth parameters. For the laser surface scanning, two examiners performed replicate measurements with an interval of 1 week. In the conventional direct measuring, the first examiner took replicate measurements with a 1-week interval. To assess intra- and inter-examiner reliabilities, the intraclass correlation coefficient was used. Analysis of variance with repeated measures for each parameter was performed to compare the conventional method with the 3D scanning method. Both the 3D scanning and conventional methods showed excellent intra-examiner reliabilities, and the 3D laser scanning method also showed excellent inter-examiner reliability. A statistical difference between the two examiners was found only in nasal breadth in the 3D laser scanning method. There was no significant difference between the two measuring methods, though the 3D laser scanning method tended to give a slightly lower reading. Collectively, the 3D laser scanning method with point localization is a useful method with excellent reliability, and it can replace the conventional direct measuring method in craniometry.     

An examination of handwritten signatures forged using photosensitive signature stamp

Signature examination is the most common examination performed by any document examiner. Determination of the authenticity of a handwritten signature on a questioned document is an important task for forensic document examiners in the forensic science field. As a result of continuous developments in technology, a signature stamp can now be created using a photosensitive seal to enable the reproduction of a handwritten signature. These stamps are commonly used in China and several other countries. In this study, 10 types of black photosensitive stamp-pad ink, 10 brands of fountain pen ink, 15 types of black gel ink and six types of black erasable gel ink found on the Chinese domestic market were collected and 10 photosensitive signature stamps were created using the signatures of 10 people. Microscopic analysis, infrared (IR) and fluorescence analyses and microspectrophotometry (MSP) techniques were used to examine the resulting photosensitive signature stamp impressions when applied to printing papers, writing papers and invoice papers. By comparing the printing and spectral characteristics of the photosensitive signature stamp impressions with those of the signatures executed using the fountain pens, gel pens and erasable gel pens, it was possible to determine whether each signature was written or stamped using a photosensitive signature stamp. To validate these results, a 96.7% absolute accuracy and a 99.3% detection rate were achieved over a total of 150 blind tests conducted by five forensic document examiners, thus demonstrating that a combination of the four analysis methods used in this work can provide a more scientific approach and improve the accuracy and the detection rate of the examination process.

KEY POINTS

• A signature stamp is a photosensitive seal made in the style of a handwritten signature.
• Although microscopic analysis can usually provide better examination results, a comprehensive examination method that includes microscopic analysis and ink composition analysis is required to improve the accuracy and the detection rate of the examination process.
• This study collected and tested photosensitive stamp-pad inks, fountain pen inks, gel inks and erasable inks.
• Infrared and fluorescence analyses and microspectrophotometry were able to distinguish the photosensitive ink from both erasable ink and fountain pen ink.

Supplemental data for this article are available online at https://doi.org/10.1080/20961790.2021.1898755.