Age determination of blood spots in forensic medicine by force spectroscopy

We present a new tool for the estimation of the age of bloodstains, which could probably be used during forensic casework. For this, we used atomic force microscopy (AFM) for high-resolution imaging of erythrocytes in a blood sample and the detection of elasticity changes on a nanometer scale. For the analytic procedure we applied a fresh blood spot on a glass slide and started the AFM detection after drying of the blood drop. In a first step, an overview image was generated showing the presence of several red blood cells, which could easily be detected due to their typical "doughnut-like" appearance. The consecutively morphological investigations in a timeframe of 4 weeks could not show any alterations. Secondly, AFM was used to test the elasticity by recording force-distance curves. The measurements were performed immediately after drying, 1.5 h, 30 h and 31 days. The conditions were kept constant at room temperature (20 degrees C) and a humidity of 30%. The obtained elasticity parameters were plotted against a timeline and repeated several times. The elasticity pattern showed a decrease over time, which are most probably influenced by the alteration of the blood spot during the drying and coagulation process. The preliminary data demonstrates the capacity of this method to use it for development of calibration curves, which can be used for estimation of bloodstain ages during forensic investigations.     

Carbon and nitrogen stable isotopes as indicative of geographical origin of marijuana samples seized in the city of São Paulo (Brazil)

The drug trafficking is one of the most serious problems related to the Public Safety in Brazil, especially in the most populous areas of the country, as is the case of the city of São Paulo. In this work, it was developed a methodology that can help tracking the traffic routes of marijuana samples seized in the city of São Paulo, based on stable carbon and nitrogen isotopes, which are related to the climate and plant growth conditions. A model to classify the origin of unknown samples was built using linear discriminant analysis based on about 150 samples apprehended in the main producing regions of the country. Results for 76 samples seized in the city of São Paulo showed that most of them were cultivated in a humid region with the same origin as those from Mato Grosso do Sul. The provenance of 13 outliers samples from Northeast region (an important producing region) also were evaluated and some of them presented same profile of those from Mato Grosso do Sul, pointing to the existence of the traffic routes between the Northeast and Midwest region, probably as a consequence of the intensive field raids by Brazilian Federal Government since 1999.     

Pattern detection in forensic case data using graph theory: application to heroin cutting agents

Pattern recognition techniques can be very useful in forensic sciences to point out to relevant sets of events and potentially encourage an intelligence-led style of policing. In this study, these techniques have been applied to categorical data corresponding to cutting agents found in heroin seizures. An application of graph theoretic methods has been performed, in order to highlight the possible relationships between the location of seizures and co-occurrences of particular heroin cutting agents. An analysis of the co-occurrences to establish several main combinations has been done. Results illustrate the practical potential of mathematical models in forensic data analysis.     

Confirmation by LC-MS of drugs in oral fluid obtained from roadside testing

The aim of this study was to assess the effectiveness of two current on-site oral fluid (OF) drug detection devices (OraLab and Dr?ger), as part of the Spanish participation in the Roadside Testing Assessment Project (ROSITA Project). The study was done in collaboration with the Spanish Traffic Police, in Galicia (NW Spain), during 2004 and 2005. A total of 468 drivers selected at the police controls agreed to participate through informed consent. In addition, saliva samples were collected and sent to the laboratory to confirm the on-site results. For this purpose, two different analytical liquid chromatography-mass spectrometry (LC-MS) methods were used to detect 11 drugs or metabolites in a 300 microL sample. Simultaneous analysis of morphine, 6-acetylmorphine, amphetamine, methamphetamine, MDA, MDMA, MDEA, MBDB, cocaine and benzoylecgonine was carried out using 100 microL of oral fluid, after an automated solid phase extraction. A different LC-MS method was performed to detect Delta(9)-THC in 200 microL of oral fluid using liquid-liquid extraction with hexane at pH 6. Both methods were fully validated, including linearity (1-250 ng/mL, 2-250 ng/mL) recovery (>50%), within-day and between-day precision (CV<15%), accuracy (mean relative error<15%), limit of detection (0.5 and 1 ng/mL), quantitation (1 and 2 ng/mL) and matrix effect. All of the positive cases and a random selection of 30% of the negatives were analyzed for confirmation analysis. Good results (sensitivity, specificity, accuracy, positive predictive value and negative predictive value>90%) were obtained for cocaine and opiates by OraLab, and for cocaine by Dr?ger. However, the results for the other compounds could be improved for both detection devices. Differences in the ease of use and in the interpretation mode (visual or instrumental) were observed.     

Homicide-suicide - an event hard to prevent and separate from homicide or suicide

Suicide preceded by homicide is a rare but tragic event that often shocks the whole community. Annual rates show considerable variation, though not as great as the incidence of homicides. Within the industrialized nations, Finland's prevalence rates for homicide-suicide have been mid-range. The National Suicide Prevention Project recorded and carefully analysed all suicides committed in Finland during a 12-month period. In this material of almost 1400 suicides, 10 verified homicide-suicide cases were found. The perpetrator was male in all but one case, and all the victims were family, 9/10 being spouses and/or children. The most typical homicide-suicide seemed to be a man shooting a family member during a separation process. No perpetrator was found suffering from a psychotic disorder but three had major depression. The homicide-suicides were compared with the suicides and statistically significant differences emerged in two variables: shooting was more often the method used in the homicide-suicide cases, which, furthermore, were more likely to involve a divorce or recent rupture in another long-term intimate relationship. Sharing few common variables with either homicide or suicide, homicide-suicide appears to be a distinct phenomenon whose prevention would seem to be extremely difficult on the individual level. Since shooting is the most common method of homicide-suicide, firearm licenses should be more restricted.     

Allele frequencies of six miniSTR loci (D10S1248, D14S1434, D22S1045, D4S2364, D2S441 and D1S1677) in a Spanish population

Allele frequencies and forensic parameters for six miniSTR autosomal loci (D10S1248, D14S1434, D22S1045, D4S2364, D2S441 and D1S1677) were obtained from a sample of 264 unrelated individuals from Spain. No significant deviations from Hardy-Weinberg expectations were found. Due to the small PCR products (<125 bp), the use of these non-CODIS (NC) miniSTRs can increase the probability that a degraded sample can be typed. Additionally, these systems can be used in routine paternity analyses where more markers are needed to increase the power of exclusion or in complex paternity cases (e.g. involving closely related individuals).     

证据法、诉讼法和实体法的关系?

我昨天给大家概述了证据法的许多基础性问题,这些问题是构建一部理性证据法所需考虑和安置的问题。今天,我将通过对证据法、诉讼法与实体法之间关系的考察,对昨天简要触及的一些问题做深入讲解。     

美国法学教育和法律职业养成

美国法学教育是普通法传统下三年制研究生层次的职业教育。美国法学院力求教会学生学会在广泛学科领域中进行法律分析、掌握法律技能和理解职业价值。美国法学教育也遭到了各种各样的批评,有人批评法学院是否有效地为学生从事法律职业提供了充分准备。本文对美国法学教育作了概括介绍,分析了美国法学教育面临的挑战,并介绍了对当前的法学教育模式所提出的批评等内容。     

司法审判公开与德国当代判例数据库

本文介绍了西方司法审判公开制度的发展情况,并同时介绍了与此相对应的德国当代判例数据库：德国判例公开数据库、德国免费判例数据库、德国商业性判例数据库等。     

交警趣事

我在做了30年的警察之后最近刚刚退休。回顾自己的职业生涯,使我感到非常骄傲的是,我有幸为大家服务并且和许多特别好的人肩并肩地工作。但是,我仍想说的是,为了在职业生涯中始终保持精神健全和通情达理,适当的幽默感是不可缺少的。例如,执法警官必须要做的最危险的工作之一就是,在目睹了违法行为的发生之后走到一辆完全陌生的车辆前跟这辆车的驾驶员对话。这样的对话有的时候可能是非常好笑的,会令你终生难忘。下面就举几个例子。