Establishing an integrated pipeline for automatic and efficient detection of trace DNA encountered in forensic applications

The analysis of trace DNA is a crucial component in forensic applications. Biological materials containing low-level DNA collected at crime scenes, such as fingerprints, can be valuable as evidence. Automatic detection of biological samples has been largely embraced in forensic applications to meet the increasing throughput requirements. However, the amount of DNA automatically retrieved from trace evidence often tends to be small and unstable, ultimately resulting in poor detection of DNA profiles. Thus, in this work, we introduced a robust DNA extraction and purification platform named Bionewtech® BN3200 (Bionewtech®, Shanghai, China) with the goal of constructing a rapid automatic detection system for trace DNA. The establishment of automatic detection system for trace DNA mainly encompassed two parts: assessing the sensitivity of automatic extraction platform and screening the optimal short tandem repeat (STR) typing kit. The sensitivity of Bionewtech® BN3200 platform based on Ultra-sensitive DNA Extraction kit was initially estimated, demonstrating that this extraction platform might contain large potential in the trace DNA extraction. For the amplification part, three sets of commercial multiplex STR typing kits were selected as candidates, and the amplified products were further genotyped on the Applied Biosystems 3500xl Genetic Analyzer. After comparation, SiFa™ 23 Plex Kit was determined as the most suitable amplification system for trace DNA. Eventually, the newly exploited trace DNA detection system was successfully implemented in the detection of fingerprints derived from glass surfaces with the five-seconds contact time. As a result, the DNA recovered from the fingerprints fluctuated approximately from 57.60 pg to 18.05 ng, in addition, over 70% of the total STR loci were detected in 75% of the fingerprint samples.     

网络传销犯罪特征及侦破难点剖析

网络传销犯罪比传统意义上的传销犯罪传播范围更广、速度更快、破坏力更强,已经成为阻碍我国经济社会发展的重大不稳定因素。这种新型犯罪改变了以往传销犯罪"偷偷摸摸"的面目,而是建立公开网站,打着高科技、新政策等旗号诱骗公众加入,更具隐蔽性与迷惑性。当前,公安部门在打击网络传销犯罪上还面临着诸多困难,需要在实践中不断突破与解决。     

Hospital Wet Mount Examination for the Presence of Sperm in Sexual Assault Cases is of Questionable Value

Many protocols for the examination of sexual assault victims include the preparation of vaginal wet mount slides to determine whether sperm are present and if so, whether the sperm are motile. We have reviewed findings in 501 case reports to compare the efficiency of sperm detection on wet mounts to subsequent crime laboratory results of sperm searches on vaginal swabs. Sperm were detected on wet mounts in only 41% of cases in which sperm were detected in the crime laboratory. Motile sperm were observed in only 12% of cases reporting a 0–9 h postcoital interval; in three cases, motile sperm were seen at 15 h and beyond, indicating that motile sperm are not reliable evidence of a short postcoital interval. These findings demonstrate that wet mount examinations are of little value in guiding subsequent analyses in the crime laboratory or in corroborating other investigative aspects of the case.     

Deception among pairs: “Let's say we had lunch and hope they will swallow it!”

Deception research has neglected the fact that legal-workers often have to try to detect deceit on the basis of statements derived from pairs of suspects, each having been interrogated repeatedly. To remedy this shortcoming we conducted a study where each member of 10 truth-telling pairs and 10 lying pairs was interrogated twice about an alibi. One hundred and twenty undergraduate students were enrolled as lie-catchers. The main findings were that (a) overall deception detection accuracy was modest; (b) lie-catchers given access to a large number of statements did not outperform lie-catchers given access to a lesser number of statements; (c) when asked to justify their veracity assessments the most frequently reported cue was ‘consistency within pairs of suspects’; (d) all cues to deception were of low diagnostic value. Psycho-legal aspects of integrating sequential information in deception detection contexts are discussed.     

Automation of a screening polygraph test increases accuracy

Abstract

The present study examined the effects of automating the Relevant–Irrelevant (RI) psychophysiological detection of deception test within a mock-screening paradigm. Eighty participants, recruited from the local community, took part in the study. Experimental design was a 2 (truthful/deceptive) by 2 (human/automation) factorial. Participants in the deceptive conditions attempted deception on two items of an employment application. Examinations conducted with the automated polygraph examination were significantly more accurate than examinations conducted by the human polygraph examiner. Statistical analyses revealed different patterns of physiological responses to deceptive items depending upon the automation condition. Those results have potentially interesting theoretical implications. The results of the present study are clearly supportive of additional efforts to develop a field application of an automated polygraph examination.     

Age and lineup type differences in the own-race bias

The own-race bias (ORB) suggests that recognition for faces of one's own race is superior to recognition of other-race faces. A popular explanation for the ORB is amount of interracial contact, which may have cohort effects for older and younger adults. We compared White younger and older adults on the ORB utilizing a hybrid facial recognition and full diagnostic lineup (i.e., simultaneous and sequential target absent and target present lineups) paradigm. Both younger and older adults demonstrated an ORB. Signal detection estimates suggest younger adults compared to older adults have better discrimination accuracy for own-race over other-race faces. Interracial contact did not explain recognition for younger adults, but was related to a shift in response criterion for older adults.     

Problems in expert deception detection and the risk of false confessions: no proof to the contrary in Levine et al. (2014)

Lie-detection research has shown that observers who rely on nonverbal cues or on verbal cues correctly classify on average 54% of truth tellers and liars. In addition, over the years, countless numbers of innocent people have made false confessions and, in analysing the problem, researchers have implicated both a suspect's vulnerability and the persuasive influence of certain police interrogation tactics. Levine et al. (2014) aim to contribute to these vast bodies of literature by reporting two studies purportedly showing that expert interviewers – when they are permitted to question interviewees – can achieve almost perfect accuracy without eliciting false confessions. We argue that theoretical and methodological aspects of these studies undermine the reliability and validity of the data reported, that as a result the studies do not contribute to the scientific literatures on lie detection and false confessions in any meaningful way, and that the results are dangerously misleading.     

Detecting concealed information: The role of individual differences in executive functions and social desirability

The aim of the study was to assess the relationship between deception efficiency and individual differences in executive functioning (EF) and personality, with a particular focus on the influence of social desirability. A mock crime scenario was used, followed by a Concealed Information Test based on reaction times (RT-based CIT). Individual measures of EF (inhibition, shifting, and working memory [WM]) and personality (the Eysenck Personality Questionnaire – Revised, EPQ-R), plus a measure of social desirability (Balanced Inventory of Desirable Responding, BIDR) were collected in a distinct session. Results indicated that better executive functions were associated with faster responses to irrelevant items in the RT-based CIT. In a regression analysis, individual differences in shifting and spatial WM were significant predictors of the extra-time taken to lie, compare to truth-telling. No significant relations between deception outcomes and personality measures were noted. Looking at social desirability, the Impression Management scale predicted a further portion of variance in the extra time required to lie, beyond the contribution of executive functions. The utility of an individual differences approach to deception is advocated.     

Children's truthful and deceptive testimonies: How camera perspective affects adult observers’ perception and assessment

Abstract

This experimental study investigates adults’ perception and assessments of children's testimonies as a function of camera shot (close-up shot vs medium shot vs long shot) and camera focus (child only vs child and interviewer). Truth-telling and lying children were interviewed and videotaped simultaneously by four cameras, each taking a different visual perspective (‘close-up shot/child only’, ‘medium shot/child only’, ‘medium shot/child and interviewer’, ‘long shot/child and interviewer’). Mock jurors (N=256) watched the videotaped testimonies and rated their perception of the children's statement and appearance, and assessed the children's veracity. Children seen in long shot were perceived as more neutral and relaxed, and children seen in close-up were perceived as having to think harder. The adult's deception detection accuracy was at chance level. The results suggest that legal policy-makers should consider the outcome of psycho-legal research on camera perspective when establishing and/or reforming standards for police interviews and courtroom procedures.     

DART-TOFMS法检测发射药中的硝化甘油和Ⅱ号中定剂

目的建立一种快速检测发射药中主要成分硝化甘油（NG）、Ⅱ号中定剂（C2）的方法。方法采用实时直接分析飞行时间质谱技术（DART-TOFMS）,在正负离子模式下,通过特征分子离子精确质量数进行检材中NG和C2的定性分析。结果 NG的检测限为0.044mg/L,C2的检测限为0.0032 mg/L,检测时间仅在1min以内。结论该方法无需样品前处理和预分离,且具有快速、不受样品存在形态限制等优点,已用于案件检验,为案件的快速侦破发挥了重要的作用。