K9 water searches: scent and scent transport considerations

Increased use of water search dogs for detecting submerged bodies has created the need for a better understanding of scent emanating from the bodies and how it transits the water to the dog's nose. A review of recent literature identifies likely scent sources, potential scent transport processes, and research needs. Scent sources include gases in bubbles or dissolved in the water, liquids as buoyant plumes and droplets or dissolved in the water, and solids consisting of buoyant particulates with secretions, bacteria, and body fluids. Potential transport processes through the water include buoyancy, entrainment, and turbulence. Transport processes from the water surface into the air include volatilization and evaporation enhanced by bubble bursting, breaking waves, splashing, and wind spray. Implications for the use of water search dogs are examined. Observations of submerged, decomposing bodies are needed to quantify the physical and chemical characteristics of the scent and scent transport processes.     

Visualization of latent fingermark corrosion of brass, climatic influence in a comparison between the U.K. and Iraq

Through a comparison of fingermark sweat corrosion of α phase brass in both the U.K. and Iraq, we show how samples from Iraq have improved fingermark corrosion over U.K. samples that require no additional enhancement prior to visualization. Over 50% of Iraqi samples produced fingermark corrosion with full ridge detail compared with 0% from the U.K. X-ray photoelectron spectroscopy analysis of the fingermark corrosion products showed that Iraqi samples exhibit more dezincification with the Zn:Cu ratio averaging 1:1.82 compared with 1:3.07 for U.K. samples. Auger spectroscopy showed the presence of both zinc oxide and copper (I) oxide. No copper (II) was observed on the surface of the corroded brass. Opportunities to exploit the optical properties of these thin film oxides to enhance the visualization of fingermark corrosion are considered, and the potential to use fingermark corrosion of metal as a means of visualizing fingerprints in war zones is discussed.     

论视频监控的犯罪预防功能及犯罪侦查价值

各国的犯罪预防理论发展至今,已经形成了比较完善的犯罪预防体系,主要包括司法预防、社会预防和情景预防三种模式。在我国的犯罪预防体系中,向来重视司法预防和社会预防,而对情景预防关注不够,情景预防措施尚不完善。作为一种对犯罪的干预,视频监控是一种对情境犯罪的干预,研究发掘其在犯罪预防中的作用对完善犯罪预防体系具有重要意义。同时,视频监控系统在犯罪侦查方面也具有重要作用。     

应用多种STR技术对基因嵌合体进行亲权鉴定分析

目的 查找嵌合基因的来源并进行父母和孩子的亲权鉴定.方法 采用Chelex-100法抽提基因组DNA,用复合扩增和荧光检测技术对STR、X-STR和Y-STR基因座进行分型.结果 父亲为XX,XY基因嵌合体,其能够提供给孩子必须的遗传基因.结论 父亲为被检孩子的生物学父亲.     

视频侦查规范化研究

视频侦查是指侦查机关根据案件的需要,通过视频监控资料的调取、观看、分析和应用四个环节,实现对犯罪的动态分析和综合判断,以发现和确定犯罪嫌疑人、寻找破案线索,为案件侦查提供方向的一种侦查措施。视频侦查已成为继刑事技术、行动技术、网侦技术之后侦查破案的技术支撑和新的破案增长点,成为强化社会治安控制的有效手段,对提高侦查机关打击犯罪的效能具有重大意义。     

Unicorns or Tiger Woods: Are Lie Detection Experts Myths or Rarities? A Response to On Lie Detection “Wizards” by Bond and Uysal

Bond and Uysal (this issue) complain that expert lie detectors identified by O'Sullivan and Ekman (2004) are statistical flukes. They ignore one class of experts we have identified and misrepresent the procedures we use to identify the others. They also question the psychometric validity of the measures and protocol used. Many of their points are addressed in the chapter they criticize. The fruitfulness of the O'Sullivan-Ekman protocol is illustrated with respect to improved identification of expert lie detectors, as well as a replicated pattern of errors made by experts from different professional groups. The statistical arguments offered confuse the theoretical use of the binomial with the empirical use of the normal distribution. Data are provided that may clarify this distinction.     

Psychopathy and Nonverbal Indicators of Deception in Offenders

The current study examined psychopathy and nonverbal indicators of deception in an incarcerated sample. Nonverbal behaviors were coded from videotapes of 45 male offenders telling true and fabricated stories about crimes. Interpersonal features of psychopathy were associated with inflated views of lying ability, verbosity, and increases in blinking, illustrator use, and speech hesitations. While lying, the more psychopathic offenders spoke faster and demonstrated increases in blinking and head movements. Indicators of deception in offenders were somewhat different from those typically observed in non-offender populations. These findings indicate that personality factors may have an impact on nonverbal indicators of deception in criminal justice settings where the detection of deception is of utmost concern.     

Visual detection of trace nitroaromatic explosive residue using photoluminescent metallole-containing polymers

The detection of trace explosives is important for forensic, military, and homeland security applications. Detection of widely used nitroaromatic explosives (trinitrotoluene [TNT], 2,4-dinitrotoluene [DNT], picric acid [PA]) was carried out using photoluminescent metallole-containing polymers. The method of detection is through the quenching of fluorescence of thin films of the polymer, prepared by spray coating organic solutions of the polymer, by the explosive analyte. Visual quenching of luminescence (lambda(em) approximately 400-510 nm) in the presence of the explosive is seen immediately upon illumination with near-UV light (lambda(ex)=360 nm). Detection limits were observed to be as low as 5 ng for TNT, 20 ng for DNT, and 5 ng for PA. In addition, experiments with normal production line explosives and their components show that this technology is also able to detect composition B, Pyrodex, and nitromethane. This method offers a convenient and sensitive method of detection of trace nitroaromatic explosive residue.     

1,2,4‐Triazine‐Based Chromogenic Reagents for the Detection of Microtraces of Various Metals Left on Human Skin*

Abstract: This article extends the application of 1,2,4‐triazine‐based chromogenic reagents to the detection of nonferrous metal traces left on contact with canvas and human skin. The possibility of detection of iron traces resulting from contact with objects made of stainless steel was investigated as well. Additionally, the ability of triazines to form chromatic complexes with Zn²⁺, Ni²⁺, Co²⁺, Cu²⁺, Cr³⁺, and Al³⁺ ions was studied spectrophotometrically. Molar absorption coefficients, ranging from 8.8 to 29.9 × 10³/M/cm, provide high sensitivity of 1,2,4‐triazines toward nonferrous ions, thus, enabling the detection at concentrations as low as a few μM. The method was sensitive enough to detect traces resulting from a 1‐min contact with a stainless steel made object, which is commonly considered as a corrosion‐resistant material. The amounts of metal ions transferred to the skin after a 2‐min contact with objects made of brass, zinc, and copper were sufficient to develop chromatic imprints.     

Transfer of Triazine‐iron(II) Chromic Complexes Left by Iron Items on Textile Background and Human Skin

Abstract: The research is focused on the detection and transfer of iron traces left by iron items on clothing and human skin. The method is based on the formation of colored complexes between ferrous ions and five synthesized, mostly new triazines. Iron traces originally were left by iron rings on slightly wetted (artificial sweat) cotton fabrics and subsequently transferred to a separate textile substrate. Prior to the use of trazines the contact spots were treated with a new inorganic reducing agent (Sn²⁺) to reduce Fe³⁺ to Fe²⁺. The method is sensitive to detect iron traces on wetted canvas after 10 min contact with iron items. More spectacular results were obtained for traces left on human palm even after very short contact (10 sec). The new iron‐trace‐transfer method eliminated the contact of triazines solutions with human skin. Transmission visible spectra of Fe(II)–triazine complexes were determined.