The importance of forensic evidence for decisions on criminal guilt

Recent studies have found that the general public perceives forensic evidence to be relatively inaccurate and to involve high levels of human judgement. This study examines how important the general public finds forensic evidence by comparing decisions on guilt and punishment in criminal cases that involve forensic versus eyewitness testimony evidence and examining whether a CSI effect exists. Specifically, this experimental survey study utilized a 2 (crime type: murder or rape) × 4 (evidence type: DNA, fingerprint, victim eyewitness testimony, or bystander eyewitness testimony) ? 1 (no victim testimony for murder scenario) design, yielding seven vignettes scenarios to which participants were randomly assigned. Results indicate that forensic evidence was associated with more guilty verdicts and higher confidence in a guilty verdict. Forensic evidence did not change the expected sentence length and did not generally affect the ideal sentence length. However, for rape, respondents believed that the defendant should receive a longer sentence when forensic evidence was presented but forensic evidence did not alter likely sentence that respondents expected the defendant to receive. The results of this study did not support a CSI effect. Overall, this study suggests that forensic evidence – particularly DNA – has a stronger influence during the verdict stage than the sentencing stage.     

Voicing concerns: The balance between data protection principles and research developments in forensic speech science

The status of forensic speech recordings among existing data protection guidance is not clear. The inherent nature of voice and the way in which forensic speech casework is currently allocated mean that there are additional barriers to incorporating real casework data into research activities. The key objective of this work is to explore data protection solutions that could enable the forensic speech science community to responsibly use real casework data for research and development purposes. While reviewing relevant guidance and rulings, issues such as proportionality, opportunism and data minimisation are addressed, as well as where voice sits in relation to the definition of “biometric data”. This paper ultimately places forensic speech recordings in the data protection context to illuminate the specific issues that arise for this data type.     

Whole bovine blood use in forensic research: Sample preparation and storage considerations

Mammalian whole blood sources are often used for forensic research and training when human samples cannot be sourced. While porcine, ovine and equine blood have been shown to be viable alternatives to whole human blood for forensic purposes, procurement can still pose a problem, especially for smaller and remote institutions. This work explores the use of whole bovine blood for basic bloodstain simulation. Sample preparation through the addition of ACD-A anticoagulant was optimized and storability was explored. Viscosity, surface tension, density, and packed cell volume, four fluid properties relevant to bloodstain pattern analysis, were monitored over four days and in two temperature conditions. Linear mixed models accounting for variation in the donor demonstrated that these fluid properties of the bovine blood changed predictably over time and with temperature. Whole bovine blood with 12.5% v/v ACD-A was found to be viable for use in basic bloodstain simulation at ambient and physiological temperature.     

Interpretation,confidence and application of the standardised terms: Identified,Probable, Possible,Exclude and Insufficient in forensic odontology identification

Forensic odontology identification scales are used to express certainty of identifications of deceased persons. These standardized scales are assumed to convey unambiguous expert opinions and facilitate communication between forensic odontologists and end users. However, to date no studies have investigated how the experts interpret and use these scales.Forensic odontology identification scales are used to express certainty of identifications of deceased persons. These standardized scales are assumed to convey unambiguous expert opinions and facilitate communication between forensic odontologists and end users. However, to date no studies have investigated how the experts interpret and use these scales.This paper aims to examine the interpretation of the DVISYS forensic identification scale and choices of the levels in the scale subsequent to, and derived from, comparison of pairs of dental radiographs by extending the analysis of the data collected in the study by Page and Lain et. al. 2017.The studied variables: self-reported confidence, forced binary decision of match and non-match, choice of level in the DVISYS scale (Identified, Probable, Possible, Insufficient and Exclude) were further analysed in this study using mixed models for relationships between the choices of level in the identification scale and the fundamental beliefs of likelihood of identification.The results of this further analysis showed that the reported confidence of the decisions was correlated to the difficulty of cases, and as confidence decreased the use of less definitive terms (‘Probable’, ‘Possible’ and ‘Insufficient’) increased. ‘Probable’ and ‘Possible’ were used mainly in underlying beliefs below that of ‘Identified’ whereas ‘Insufficient’ was used mainly to convey a sublevel of ‘Exclude’. The use of ‘Insufficient’ in this study was not consistent with the prescribed definition of the term.The participants of the original study were not aware of the difficulty grading of the cases nor were required to grade them, however the reported confidence was systematically correlated to difficulty. Furthermore, indicated confidence level was correlated with choice of level on the scale in general, but the interpretation of the definition and application of the terms varied.The findings reported here contribute to the foundational knowledge of factors governing the interpretation and application of the DVISYS forensic odontology identification scale and suggest that this scale may need to be modified.     

Application of fragment analysis based on methylation status mobility difference to identify vaginal secretions

Identifying vaginal secretions attaching or adhering to a suspect’s belongings would be beneficial for reconstructing the events that have taken place during a sexual assault. The present study describes a novel approach to identify vaginal secretions by fragment analysis using capillary electrophoresis, based on the mobility differences of PCR amplicons from bisulfite-treated DNA depending on methylation status. We targeted three genome regions including each of three vaginal secretion-specific methylated CpG sites reported previously: cg25416153, cg09765089, and cg14991487. In all three genome regions, the amplicon peaks for methylated genomic DNA (gDNA) sequences were only detected in vaginal samples, whereas samples of other body fluids (blood, saliva, semen, and deposit on skin surface) only showed amplicon peaks for unmethylated gDNA sequences. In vaginal secretions, the methylation ratio of each of the three targeted regions between samples was variable, while the ratios at the three regions in each sample were similar. Furthermore, commercial vaginal epithelial cells were completely methylated at the three regions. Therefore, vaginal secretion-specific methylation may derive from vaginal epithelial cells present in the sample.In forensic cases with a limited amount of DNA, the reproducibility of a detected peak using the present method is not high due to degradation of DNA by bisulfite treatment and subsequent stochastic PCR bias. However, it was possible to detect peaks from methylated DNA sequences by performing PCR and capillary electrophoresis in triplicate after bisulfite treatment, even when bisulfite treatment was performed using 0.5 ng of gDNA from vaginal secretions. In addition, the level of methylation at each targeted region was found to be stable in vaginal secretions stored for 1 year at room temperature. Therefore, we conclude that detection of the visual peak from vaginal secretion-specific methylated DNA sequence is useful to prove the presence of vaginal secretions. This approach has the potential to analyze multiple marker regions simultaneously, and may provide a new multiplex assay to identify various body fluids.     

Evaluation of alizarin and purpurin dyes for their ability to visualize latent fingermark on porous surfaces

Anthraquinones are a group of dye with many members and a wide range of industrial uses ranging from food, textiles to printing. Even though the reactions of anthraquinone dyes with amino acids are known, they have not yet been subjected to an examination regarding their ability in fingermark detection. In the presented study, the potential of alizarine and purpurin, natural anthraquinone dyes, as a fingermark reagent was examined in comparison with ninhydrin and lawsone. Alizarin and purpurin react with latent fingermark residue on copier paper and thermal paper to yield yellow-orange coloured impressions. The products formed also display photoluminescence properties when illuminated at 440 nm viewed through red filter. Both natural anthraquinone dyes exhibited some superior properties at the development of latent fingermarks on these surfaces compared to ninhydrin and lawsone.     

浅析医疗纠纷案件久拖不决的原因及对策建议

随着我国依法治国方略的不断践行，法制宣传教育的不断深入，公民的法律意识、维权意识在不断提高，医疗纠纷案件也逐年增加。影响案件解决的因素复杂、多样，本文主要从调解解决、司法鉴定环节、法院诉讼几个阶段分析造成医疗纠纷案件久拖不决的原因以及提出相应的对策建议。     

219例损伤与疾病关系的尸检案例分析

目的探讨损伤与疾病关系案例的特点。方法对本教研室近20年的219例涉及损伤与疾病关系的尸检案例进行回顾性研究。结果①219例中,20~59岁青壮年占71.7%;伤后<24h死亡占48.9%。②损伤以拳、足等钝器伤为主,以擦伤和挫伤多见,主要位于头、胸部。③疾病以心血管疾病最多,CNS疾病次之。④损伤与疾病相关的案例占71.2%,最常见的是“疾病为主、损伤为辅”。结论损伤与疾病关系案例的死者多为男性青壮年,冠心病和病理性脑出血是两个主要的疾病;将损伤与疾病关系分为“单纯损伤致死、单纯疾病致死、损伤为主疾病为辅和疾病为主损伤为辅”四类简单而实用。     

精神分裂症患者的犯罪学特征与刑事责任能力的关系

目的探讨精神分裂症患者的犯罪学特征与刑事责任能力的关系。方法采用自行编制的司法精神病学鉴定案例登记量表,对133例精神分裂症涉嫌犯罪者的资料进行收集、整理、归纳。然后对其犯罪学特征与责任能力的关系做相关分析。结果精神分裂症患者涉嫌犯罪案件类型中,以暴力案件为主,依次为凶杀68例(51.1%)、伤害38例(28.6%)、纵火9例(6.8%)、抢劫4例(3.0%)、性犯罪3例(2.3%)。不同责任能力与犯罪相关因素的统计分析发现:诱发事件(χ2=91.779,P=0.000)、双方关系(χ2=76.449,P=0.000)、作案动机(χ2=11.9,P=0.001)、作案前准备(χ2=110.623,P=0.000)、自称遗忘(χ2=34.274,P=0.000)、作案后反应(χ2=110.923,P=0.000)、案件类型(χ2=38.638,P=0.000)有显著性差异。结论无责任能力的分裂症患者作案具有动机不明、无预谋、不分对象、不分场合、突发性、盲目性、残忍性等特点。无责任能力组和部分责任能力组的犯罪学因素中诱发事件、双方关系、作案动机、作案前准备、自称遗忘、作案后反应、案件类型有显著性差异,可作为责任能力评定的参考因素。     

家兔双前肢悬挂致死过程中的电生理研究

目的探讨悬挂体位致窒息死亡的电生理方面的机制。方法成年家兔12只,雌雄不限。随机分为两组:一组监测膈肌肌电图,另一组监测肋间肌肌电图、心电图、脑电图。取仰卧位固定,手术暴露膈肌和肋间肌,引导肌电图;同时引导标准Ⅱ导联心电图和脑电图。然后将家兔固定双前肢悬挂,连续监测实验过程中家兔的心电、脑电、肌电图的变化情况,直至其死亡。结果悬挂末期和悬挂初期相比,膈肌肌电频率下降(P<0.05)、呼吸波持续时间、振幅和面积均有延长或增多(P<0.05)、最大传导速度无变化;肋间肌仅见肌电频率下降(P<0.05);脑电振幅降低(P<0.01)、δ波增多(P<0.01)、β波减少(P<0.05);心电仅见各波形振幅的降低(P<0.01)。膈肌肌电频率的下降最早,脑电频率的下降次之,肋间肌肌电的下降最晚(P<0.01)。结论悬挂体位致窒息死亡的机制的始动因素是呼吸运动受限,并最终形成外周性呼吸肌疲劳和呼吸中枢缺氧性衰竭而发生死亡。