A solid-phase microextraction method for the detection of ignitable liquids in fire debris

A solid-phase microextraction (SPME) procedure involving direct contact between the SPME fibers and the solid matrix and subsequent gas chromatography/mass spectrometric analysis for the detection of accelerants in fire debris is described. The extraction performances of six fibers (100 mum polydimethylsiloxane, 65 mum polydimethylsiloxane-divinylbenzene, 85 mum polyacrylate, 85 mum carboxen-polydimethylsiloxane, 70 mum Carbowax-divinylbenzene, and 50/30 mum divinylbenzene-Carboxen-polydimethylsiloxane) were investigated by directly immersing the fibers into gasoline, kerosene, and diesel fuel. For simulated fire debris, in the direct contact extraction method, the SPME fiber was kept in contact with the fire debris matrix during extraction by penetrating plastic bags wrapping the sample. This method gave comparable results to the headspace SPME method in the extraction of gasoline and kerosene, and gave an improved recovery of low-volatile components in the extraction of diesel fuel from fire debris. The results demonstrate that this procedure is suitable as a simple and rapid screening method for detecting ignitable liquids in fire debris packed in plastic bags.     

Case report: Etizolam and its major metabolites in two unnatural death cases

A simultaneous analytical method for etizolam and its main metabolites (alpha-hydroxyetizolam and 8-hydroxyetizolam) in whole blood was developed using solid-phase extraction, TMS derivatization and ion trap gas chromatography tandem mass spectrometry (GC-MS/MS). Separation of etizolam, TMS derivatives of alpha-hydroxyetizolam and 8-hydroxyetizolam and fludiazepam as internal standard was performed within about 17 min. The inter-day precision evaluated at the concentration of 50 ng/mL etizolam, alpha-hydroxyetizolam and 8-hydroxyetizolam was evaluated 8.6, 6.4 and 8.0% respectively. Linearity occurred over the range in 5-50 ng/mL. This method is satisfactory for clinical and forensic purposes. This method was applied to two unnatural death cases suspected to involve etizolam. Etizolam and its two metabolites were detected in these cases.     

Learning disabilities and delinquency: a study of Israeli prison inmates

Research consistently illustrates that several intellectual disabilities--namely, learning disabilities (LD), low intelligence, challenging behavior, and inadequate adaptive behavior, as well as attention deficit hyperactivity disorder (ADHD)--are considered risk factors for antisocial and criminal behavior. Although much attention has been paid to the relationship of LD, ADHD, and criminal behavior, three research topics have been overlooked: the frequency of LD with ADHD among inmates, the relationship between LD and/or ADHD and level of education among prisoners, and the connection between LD and/or ADHD and age of criminal onset. The present study examined the frequency of LD and ADHD in a sample of Israeli-born prisoners, in addition to the frequency of each category by itself, and it investigated the relationship of LD and/or ADHD, school dropout age, and onset of criminal activity.     

Stature estimation from foot dimensions

Identification of an individual is the mainstay in forensic investigations. The dimensions of the foot have been used for the determination of sex, age, and stature of an individual. The present study examines the relationship between stature and foot dimensions among Gujjars, a North Indian endogamous group. Stature, foot length and foot breadth of 200 subjects comprising 100 males and 100 females were measured. Statistical analyses indicated that the bilateral variation was insignificant for all the measurements except foot breadth in males (p<0.01). Sex differences were found to be highly significant for all the measurements (p<0.01). Linear and multiple regression equations for stature estimation were calculated using the aforementioned variables and multiplication factors were computed. The correlation coefficients between stature and foot dimensions were found to be positive and statistically highly significant. The highest correlation coefficient between stature and foot length in males and foot breadth in females indicates that the foot length provides the highest reliability and accuracy in estimating stature of an unknown male and foot breadth in a female. Prediction of stature was found to be most accurate by multiple regression analysis.     

Experimental evaluation of rigor mortis IX. The influence of the breaking (mechanical solution) on the development of rigor mortis

In criminal proceedings involving illegally manufactured substances, evidence demonstrating the manufacture is required for successful prosecution. In many circumstances the presence of manufacturing equipment and 'recipes' are clear indicators. However establishing chemical links between starting materials and products would be beneficial additional evidence in such circumstances. Isotope analysis is becoming more commonly employed in disputes over authenticity and provenance of materials such as food stuffs or pharmaceuticals [S. Benson, C. Lennard, P. Maynard, C. Roux, Forensic applications of isotope ratio mass spectrometry--a review, Forensic Sci. Int., 157 (2006) 1-22]. We report here the results of an isotope study investigating a link between hexamine used as a starting material and the product explosive RDX, manufactured using the Woolwich process. Isotopic composition of hexamine and RDX was analysed by stable isotope ratio mass spectrometry. Five different hexamine samples were selected from a group of eleven for use in this study. One of the five hexamine samples was used twice, providing data on the reproducibility of the synthesis. Carbon and nitrogen isotope analysis of the hexamine starting material and RDX products reveals a reproducible relationship between reactant and product.     

Bloodstain pattern analysis--casework experience

The morphology of bloodstain distribution patterns at the crime scene carries vital information for a reconstruction of the events. Contrary to experimental work, case reports where the reconstruction has been verified have rarely been published. This is the reason why a series of four illustrative cases is presented where bloodstain pattern analysis at the crime scene made a reconstruction of the events possible and where this reconstruction was later verified by a confession of the offender. The cases include various types of bloodstains such as contact and smear stains, drop stains, arterial blood spatter and splash stains from both impact and cast-off pattern. Problems frequently encountered in practical casework are addressed, such as unfavourable environmental conditions or combinations of different bloodstain patterns. It is also demonstrated that the analysis of bloodstain morphology can support individualisation of stains by directing the selection of a limited number of stains from a complex pattern for DNA analysis. The complexity of real situations suggests a step-by-step approach starting with a comprehensive view of the overall picture. This is followed by a differentiation and analysis of single bloodstain patterns and a search for informative details. It is ideal when the expert inspecting the crime scene has also performed the autopsy, but he definitely must have detailed knowledge of the injuries of the deceased/injured and of the possible mechanisms of production.     

Genetic analysis of 17 Y-chromosomal STRs haplotypes of Chinese Tibetan ethnic group residing in Qinghai province of China

We have co-amplified and analyzed 17 Y-chromosomal STRs loci including European 'extended haplotypes' (DYS19, DYS389 I, DYS389 II, DYS390, DYS391, DYS392, DYS393, DYS385a,b, DYS438, and DYS439) and also six additional loci DYS437, DYS448, DYS456, DYS458, DYS635 and YGATA H4 in a population sample of 167 healthy unrelated autochthonous male individuals of Chinese Tibetan ethnic minority group residing in Qinghai province of China using a multiplex PCR system. The gene diversity values for the Y-STRs loci ranged from a minimum 0.3581 for DYS391 locus to a maximum of 0.8702 for DYS385a,b loci in Tibetan population. A total of 163 haplotypes were identified in the set of Y-STR loci, of which 159 were unique and 4 found in two individuals. The overall haplotype diversity for the set of Y-STRs loci was 0.9998, and the discrimination capacity was 0.9938. Research results will be valuable for human identification and paternity tests in the region and for Chinese population genetic study in the future.     

Controlled electrostatic methodology for imaging indentations in documents

The electrostatic process for imaging indentations on documents using the ESDA device is investigated under controlled experimental settings. An in-house modified commercial xerographic developer housing is used to control the uniformity and volume of toner deposition, allowing for reproducible image development. Along with this novel development tool, an electrostatic voltmeter and fixed environmental conditions facilitate an optimization process. Sample documents are preconditioned in a humidity cabinet with microprocessor control, and the significant benefit of humidification above 70% RH on image quality is verified. Improving on the subjective methods of previous studies, image quality analysis is carried out in an objective and reproducible manner using the PIAS-II. For the seven commercial paper types tested, the optimum ESDA operating point is found to be at an electric potential near -400V at the Mylar surface; however, for most paper types, the optimum operating regime is found to be quite broad, spanning relatively small electric potentials between -200 and -550V. At -400V, the film right above an indented area generally carries a voltage which is 30-50V less negative than the non-indented background. In contrast with Seward's findings [G.H. Seward, Model for electrostatic imaging of forensic evidence via discharge through Mylar-paper path, J. Appl. Phys. 83 (3) (1998) 1450-1456; G.H. Seward, Practical implications of the charge transport model for electrostatic detection apparatus (ESDA), J. Forensic Sci. 44 (4) (1999) 832-836], a period of charge decay before image development is not required when operating in this optimal regime. A brief investigation of the role played by paper-to-paper friction during the indentation process is conducted using our optimized development method.