Methods for ensuring the highest DNA concentration and yield in future and retrospective trace DNA extracts

In forensic laboratories, increased extraction efficiency of trace evidence is paramount because analytical success is intrinsically dependent on the quantity of DNA recovered. Moreover, highly concentrated nucleic acids are vital for effective downstream analysis and high quality results. This study investigated the efficiency of extraction with the Qiagen® QIAamp® DNA Investigator kit, and explored improvements to the methodology that would maximise the recovery of low concentration forensic samples. Controlled amounts of starting cellular material were used to mimic trace (or low level) DNA deposits prior to DNA extraction with the Investigator kit. Addition of the provided carrier RNA along with conducting two successive elutions of 50 µL improved the net recovery of DNA to 95%. Concentration with centrifugal filters post-extraction were able to concentrate DNA but a large net loss was observed. For the concentration of historic, retrospectively extracted DNA, centrifugal methods are able to concentrate DNA extracts previously too dilute for analysis. These concentrated volumes, however are small, allowing for minimal downstream analysis attempts before the sample is exhausted.     

试论侦查人员出庭作证简

英美法谚云：“警察是法庭的仆人，其主要是指警察必须根据法庭传召出庭作证”，①由此可知，侦查人员出庭作证是保证司法公正的基本制度，是法治社会的必然要求。但是，由于受传统观念的影响和客观现实的制约，该制度在我国一直难于落实，严重影响了我国人权事业的发展和法治建设进程。2010年，最高检和最高法等部门在《关于办理刑事案件排除非法证据若干问题的规定》中，首次提出讯问人员应当出庭作证；2012年，修改后《刑事诉讼法》亦明确规定侦查人员负有出庭作证的义务。这是我国刑事司法变革融入世界证据立法的具体体现，无疑是历史的进步。然而，侦查人员该以何种方式出庭作证？侦查人员作证的范围该有多大？在保障被告人权利的同时应如何保障出庭作证侦查人员的人身权利？诸如此类的一系列问题显然不容忽视。我们拟以刑事案件中“情况说明”的运用为切入点，深入分析上述问题。     

侦查人员出庭作证的法律依据辨析

侦查人员出庭作证已列入我国新一轮司法改革方案之中,但理论界对侦查人员出庭作证的法律依据一直存在争论。有的认为《刑事诉讼法》第48条规定的证人包含了侦查人员,此条即为侦查人员出庭作证的法律依据;也有的认为《刑事诉讼法》第28条关于侦查人员应当回避的规定实际上否定了侦查人员出庭作证的资格。笔者对上述意见概不同意,认为在我国现行刑事诉讼法上侦查人员出庭作证是有依据的,只是不够直接、明确,应当根据侦查人员的法定职责、审判活动的实际需要、侦查人员及侦查工作的特殊性等因素完善侦查人员出庭作证的法律依据。     

Investigating Investigators: Examining the Impact of Eyewitness Identification Evidence on Student-Investigators

This research examined the impact of eyewitness identification decisions on student-investigators. Undergraduates played the role of police investigators and interviewed student-witnesses who had been shown either a good or poor view of the perpetrator in a videotaped crime. Based on information obtained from the witness, student-investigators then chose a suspect from a database containing information about potential suspects and rated the probability that their suspect was the culprit. Investigators then administered a photo lineup to witnesses, and re-rated the probability that their suspect was guilty. Student-investigators were highly influenced by eyewitness identification decisions, typically overestimating the information gained from the identification decision (except under conditions that led witnesses to be very accurate), and were generally unable to differentiate between accurate and inaccurate witnesses.

侦查错误的原因及对策探究

侦查错误理论要求侦查主体在侦查过程中正确、全面、发展地诠释和抑制对科学侦查有负面导向的侦查主体致错因素、侦查客体致错因素、侦查方法致错因素和相关人致错因素。侦查主体未能形成正确的侦查错误意识,不明确侦查错误的表现形式和缺乏探求侦查错误成因的勇气是很难在侦查错误预防上大有所为的。所以,运用侦查学基础知识,准确界定侦查错误概念,明确侦查错误表现形式,探求侦查错误原因,进行侦查错误预防是十分必要的。     

计算机犯罪现场中的取证技术及应用

科学有效地应用计算机取证技术是侦办计算机犯罪案件的关键。计算机取证也称为计算机法医学,是把计算机运行环境看作是犯罪现场,运用相关的辨析技术,对计算机犯罪行为进行法医式的解剖,从而搜寻确认罪犯及犯罪证据,并据此提起诉讼。从理论上讲,计算机取证人员能否找到犯罪证据取决于有关犯罪证据是否被覆盖。但从海量的数据里面寻找蛛丝马迹是一件非常费时费力的工作,侦查人员必须具备相应的专业技能,并按照科学合理的步骤来实施计算机犯罪现场中的取证工作。     

Qiagen's Investigator™ Quantiplex Kit as a Predictor of STR Amplification Success from Low‐Yield DNA Samples,

Qiagen's Investigator? Quantiplex kit, a total human DNA quantitation kit, has a 200‐base pair internal control, fast cycling time, and scorpion molecules containing a covalently linked primer, probe, fluorophore, and quencher. The Investigator? Quantiplex kit was evaluated to investigate a value under which complete short tandem repeat (STR) failure was consistently obtained. Buccal swabs were extracted using the Qiagen QIAamp^® DNA Blood Mini Kit, quantified with the Investigator? Quantiplex kit using a tested half‐volume reaction, amplified with the ABI AmpFlSTR^® Identifiler kit, separated on the 3100Avant Genetic Analyzer, and data analyzed with GeneMapper^® ID v.3.2. While undetected samples were unlikely to produce sufficient data for statistical calculations or CODIS upload (2.00 alleles and 0.82 complete loci on average), data may be useful for exclusionary purposes. Thus, the Investigator? Quantiplex kit may be useful for predicting STR success. These findings are comparable with previously reported data from the Quantifiler? Human kit.     

论侦查人员的职业亚健康心理

侦查工作的行业特点决定了侦查队伍中人员存在亚健康心理状态的可能性非常大。如何　　消除亚健康心理状态所带来的不良影响,使得侦查人员回归正常心理,以便更好地开展侦查工作,已成　　为当前公安理论界和侦查心理学界迫切关注的问题。建立一套准确客观的心理健康评断标准,客观分　　析侦查人员亚健康心理的表现形式,并最终探寻维护正常心理的各项措施,是当前侦查工作改革的一个　　重要方面。     

私人侦探业的社会需求与法律认可

私人侦探业可能给社会造成一定的负面影响,但私人侦探业能更多地满足社会的就业需求,让公民实现劳动的权利;满足了信息的市场需求,分担了国家机关的责任;私人侦探业也是公民实现防卫权、知情权、辩护权的手段,是法律的内在需求。私人侦探业的合法存在与发展,为行业管理和合法经营提供法律保障。     

Investigator Argus X-12试剂盒在华东汉族人群中的法医学应用评估

目的 调查Investigator Argus X-12试剂盒中所包含的12个X-STR基因座在华东汉族人群中的遗传学数据,考察其法医学应用价值.方法 应用Investigator Argus X-12试剂盒对华东地区309名汉族无关个体进行X-STR基因座分型检测,统计分析12个X-STR基因座的频率数据、群体遗传学...