High‐Resolution Melting (HRM) of Hypervariable Mitochondrial DNA Regions for Forensic Science

Forensic strategies commonly are proceeding by analysis of short tandem repeats (STRs); however, new additional strategies have been proposed for forensic science. Thus, this article standardized the high‐resolution melting (HRM) of DNA for forensic analyzes. For HRM, mitochondrial DNA (mtDNA) from eight individuals were extracted from mucosa swabs by DNAzol reagent, samples were amplified by PCR and submitted to HRM analysis to identify differences in hypervariable (HV) regions I and II. To confirm HRM, all PCR products were DNA sequencing. The data suggest that is possible discriminate DNA from different samples by HRM curves. Also, uncommon dual‐dissociation was identified in a single PCR product, increasing HRM analyzes by evaluation of melting peaks. Thus, HRM is accurate and useful to screening small differences in HVI and HVII regions from mtDNA and increase the efficiency of laboratory routines based on forensic genetics.     

Effect of Substrate Interferences from High‐Density Polyethylene on Association of Simulated Ignitable Liquid Residues with the Corresponding Liquid

The effect of substrate interferences from high‐density polyethylene (HDPE) on the ability to associate an ignitable liquid residue with the corresponding liquid standard, using statistical procedures, is demonstrated. Gasoline, kerosene, and lighter fluid, at three different evaporation levels, were spiked onto HDPE and subsequently burned to generate simulated ignitable liquid residues (ILRs). Samples were extracted using a passive headspace procedure and analyzed by gas chromatography–mass spectrometry. The total ion chromatograms were subjected to data pretreatment procedures prior to principal components analysis and Pearson product moment correlation. Using the combination of these statistical procedures, simulated ILRs were successfully associated with the corresponding liquid type, despite the presence of compounds inherent to the HDPE substrate, as well as those resulting from pyrolysis of the substrate.     

Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS) — Preliminary study on TATP and PETN

The application of isotopic techniques to investigations requiring the provision of evidence to a Court is limited. The objective of this research was to investigate the application of light stable isotopes and isotope ratio mass spectrometry (IRMS) to solve complex forensic cases by providing a level of discrimination not achievable utilising traditional forensic techniques.Due to the current threat of organic peroxide explosives, such as triacetone triperoxide (TATP), research was undertaken to determine the potential of IRMS to differentiate samples of TATP that had been manufactured utilising different starting materials and/or manufacturing processes. In addition, due to the prevalence of pentaerythritoltetranitrate (PETN) in detonators, detonating cord, and boosters, the potential of the IRMS technique to differentiate PETN samples from different sources was also investigated.Carbon isotope values were measured in fourteen TATP samples, with three definite groups appearing in the initial sample set based on the carbon data alone. Four additional TATP samples (in a second set of samples) were distinguishable utilising the carbon and hydrogen isotopic compositions individually, and also in combination with the oxygen isotope values. The 3D plot of the carbon, oxygen and hydrogen data demonstrated the clear discrimination of the four samples of TATP. The carbon and nitrogen isotope values measured from fifteen PETN samples, allowed samples from different sources to be readily discriminated.This paper demonstrates the successful application of IRMS to the analysis of explosives of forensic interest to assist in discriminating samples from different sources. This research represents a preliminary evaluation of the IRMS technique for the measurement of stable isotope values in TATP and PETN samples, and supports the dedication of resources for a full evaluation of this application in order to achieve Court reportable IRMS results.     

Alternative fuels in fire debris analysis: biodiesel basics

Alternative fuels are becoming more prominent on the market today and, soon, fire debris analysts will start seeing them in liquid samples or in fire debris samples. Biodiesel fuel is one of the most common alternative fuels and is now readily available in many parts of the United States and around the world. This article introduces biodiesel to fire debris analysts. Biodiesel fuel is manufactured from vegetable oils and/or animal oils/fats. It is composed of fatty acid methyl esters (FAMEs) and is sold pure or as a blend with diesel fuel. When present in fire debris samples, it is recommended to extract the debris using passive headspace concentration on activated charcoal, possibly followed by a solvent extraction. The gas chromatographic analysis of the extract is first carried out with the same program as for regular ignitable liquid residues, and second with a program adapted to the analysis of FAMEs.     

Classification of black powder toners on the basis of integrated analytical information provided by Fourier transform infrared spectrometry and X-ray fluorescence spectrometry

Differentiating between black powder toners used in laser printers and copiers can be challenging for forensic examiners. One hundred and sixty-two samples from 82 different types of cartridges produced by 21 manufacturers that are currently available on the Polish market were studied using Fourier transform infrared spectrometry (FT-IR) and energy-dispersive X-ray fluorescence spectrometry (XRF). The spectra obtained by these two methods were classified into 14 groups and 28 groups using FT-IR and XRF, respectively. These classifications served as a basis for the development of an analytical scheme for differentiating black powder toners. This scheme can be used with any two methods that supply different information about an examined sample. The research will show that if two samples are similar in polymer composition (e.g., FT-IR spectra), additional quantitative elemental composition from XRF analyses may provide more discrimination. It was possible to differentiate 82.5% pairs of examined samples using only FT-IR, 90.8% pairs of examined samples using only XRF, and 95.8% pairs of examined samples using these two methods. Obtained spectra and all the available information could be used to create/build a database. The results obtained confirm the multiplicity and compatibility of toners. Additionally, it was stated that not all the samples were original (OEM).     

Elemental profiling using ICPMS of methylamphetamine hydrochloride prepared from proprietary medication using the Moscow and hypophosphorous synthesis

Illicit drugs manufactured from clandestine laboratories are often impure due to poor laboratory conditions, variations in synthesis and impure starting materials extracted either from common household products or pharmaceutical grade chemicals. Inductively coupled plasma mass spectrometry (ICPMS) can be utilised as a multi-element analytical tool to elicit the inorganic impurities which may be present in such samples, however the interpretation of the resultant data can be problematic and complex. This is particularly true when dealing with seized samples of unknown provenance. In this work, we have presented and interpreted inorganic profiles as a means to explore within and between batch variations in known provenance samples produced via two different popular synthetic routes. Samples were prepared from essential chemicals recovered from household materials and pharmaceutical medication available in the UK and extracted using different solvents. The presence or absence of elements in the final synthesised products could be linked to the synthesis route, salting out method and potentially the solvent used in the precursor extraction process.     

A metallurgical review of the interpretation of bullet lead compositional analysis

Comparison of the minor and trace element compositions of bullet lead alloys has been used by some forensic examiners to make definitive positive associations between bullets or lead fragments at a crime scene and samples of bullets linked to a suspect(s). Such conclusions have been based on the elemental analysis of isolated groups of bullets with no consideration of the metallurgical processes involved in the production and refining of the bullet lead alloys. An understanding of the metallurgy of lead refining reveals that the elements quantified in the forensic analysis are carefully controlled in the refining process and that there are logical reasons why some elements are more discriminatory than others. Data for lead alloys supplied to two major ammunition manufacturers confirm that multiple indistinguishable shipments of lead alloys from secondary lead refiners to the ammunition manufacturers are made each year and over a period of many years. The data also demonstrate that distinguishable compositions can come from the same melt or "source" of lead alloy. These results clearly indicate that bullets with indistinguishable compositions could have come from different lead "sources" produced in the same or different years. Furthermore, the observation that two bullets have a distinguishable composition does not necessarily mean that they came from a different "source".Our results show that the forensic examiner using a method of bullet lead alloy elemental analysis, which quantifies up to six elements is restricted to concluding only that indistinguishable bullets might have come from the same "source," not that they did come from the same "source". In addition, it is quite possible that multiple bullets with similar but distinguishable compositions could have come from the same "source". The authors therefore feel that there is no scientific validity to any conclusions more positive than attributing the possible association as to molten source among bullets from different samples. An understanding of the metallurgical principles operative in the melting/casting process as well as the data acquired for this study, indicate that any forensic conclusions which associate unknown bullets with the "same source", and/or "same box" should fail most or all Daubert criteria.     

The Identification of a Steel Mold’s Marks on Fake Drug Bottles

Plastic bottles are commonly encountered in drug cases where they are used as packaging materials and produced with polymers. However, to the best of our knowledge, systematic studies on the evidential values of medicine bottles have not been carried out. Therefore, it is difficult practically to determine if it is possible to identify whether the plastic bottles are manufactured with the same steel mold by comparing the manufacturing marks on plastic bottles. This paper reports the successful attempt of the authors in establishing a definite relationship between three different medicine bottles with a steel mold recovered from suspects. Fourier transform infrared spectroscopy (FT-IR) was used to characterize the chemical composition of submitted medicine bottles, and then some physical characteristics (viz., total length, length, and diameter of different parts) and the manufactured marks on these bottles were examined. The results showed that the linkage of the medicine bottles to a steel mold was successfully established using the similarities in physical characteristics and manufacturing marks. In the process, the FT-IR was only complementary in the identification process. The individual characteristics of plastic medicine bottles included the imperfections and striated impressions that were produced by the grinding patterns on the inner surface of a steel mold.     

Gunshot residue particles formed by using ammunitions that have mercury fulminate based primers.

Ammunition having mercury fulminate-based primers are commonly manufactured by Eastern Bloc countries and used extensively in the Middle East. Gunshot residue (GSR) particles formed by firing these types of ammunition were examined. It was observed that much lower percentage of mercury-containing GSR particles were found in samples taken from a shooter as compared to the percentage of such particles in samples from cartridge cases. This fact must therefore be taken into account when interpreting case results. A plausible explanation for the results described is proposed.     

Effects of Cyanoacrylate Fuming,Time After Recovery,and Location of Biological Material on the Recovery and Analysis of DNA from Post‐Blast Pipe Bomb Fragments*

Abstract: This study investigated the effects of time, cyanoacrylate fuming, and location of the biological material on DNA analysis of post‐blast pipe bomb fragments. Multiple aliquots of a cell suspension (prepared by soaking buccal swabs in water) were deposited on components of the devices prior to assembly. The pipe bombs were then deflagrated and the fragments recovered. Fragments from half of the devices were cyanoacrylate fumed. The cell spots on the fragments were swabbed and polymerase chain reaction/short tandem repeat analysis was performed 1 week and 3 months after deflagration. A significant decrease in the amount of DNA recovered was observed between samples collected and analyzed within 1 week compared with the samples collected and analyzed 3 months after deflagration. Cyanoacrylate fuming did not have a measurable effect on the success of the DNA analysis at either time point. Greater quantities of DNA were recovered from the pipe nipples than the end caps. Undeflagrated controls showed that the majority (>95%) of the DNA deposited on the devices was not recovered at a week or 3 months.     

Evaluation of 13 rapidly mutating Y-STRs on a Dravidian pedigree

The effectiveness of a rapidly mutating Y-STRs multiplex assay (RM Y-STRs) containing 13 RM Y-STR markers was compared with the AmpFℓSTR™ Yfiler™ PCR Amplification Kit (Yfiler) with conventional Y-STR markers for their efficiency in differentiating males within the same paternal lineage. Samples from 4 generations comprising 16 Dravidian males (15 father-son pairs) were analysed with both assays. Mutations were observed in 3 father-son pairs in the RM Y-STRs profiles while only 2 mutations were observed in the Y-filer profiles. Even though not many mutations were observed as anticipated, this study still emphasised the importance of RM Y-STRs when differentiation between males within the same paternal lineage is required and also indicated the need for mutation rates for different populations.     

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.     

土壤细菌群体多样性的T-RFLP分析应用探讨

目的探讨土壤细菌群体多样性的末端限制性片段长度多态性（terminal restriction fragment length polymorphism，T-RFLP）分析在法庭科学应用的相关问题。方法依据不同土壤中的细菌群体存在多样性和差异，联合利用细菌16SrDNA序列、末端限制性片段长度多态性（terminal restriction fragment length polymorphism，T-RFLP）方法对5个来源不同的土壤样品和4个同一来源土壤样品的细菌群体多样性进行比较分析，计算土壤样品间的相似系数。结果不同来源的5个土壤样品间相似系数，最大者为0．44，最小为0．3；同一来源的4个土壤样品相似系数，最大为0．87，最小为0．76。结论不同来源土壤的细菌群体多样性存在差异。     

Correlations on radioimmunoassay, fluorescence polarization immunoassay, and enzyme immunoassay of cannabis metabolites with gas chromatography/mass spectrometry analysis of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in urine specimens.

Results obtained from three commercial immunoassay kits, Abuscreen, TDx, and EMIT, commonly used for the initial test of urine cannabinoids (and metabolites) were correlated with the 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (9-THC-COOH) concentration as determined by GC/MS. Correlation coefficients obtained based on 26 (out of 1359 total sample population) highly relevant samples, are 0.601 and 0.438 for Abuscreen and TDx. Correlation coefficients obtained from a parallel study on a different set of 47 (out of 5070 total sample population) highly relevant specimens are 0.658 and 0.575 for Abuscreen and Emit. The immunoassay concentration levels, that correspond to the commonly used 15 ng/ml GC/MS cutoff value for 9-THC-COOH, as calculated from the regression equations are 82 ng/ml and 75 ng/ml for TDx and EMIT and 120 ng/ml and 72 ng/ml for Abuscreen manufactured at two different time periods. The difference of these calculated corresponding concentrations provides quantitative evidence of the reagent specificity differences.     

国产Goldeneye~(TM) 20A试剂盒性能指标验证

目的测试国产GoldeneyeTM20A试剂盒技术性能指标,评估其法医学应用能力。方法从方法学验证、准确性、峰值均衡性、灵敏度、批次间试剂及稳定性测试、耐受性、不同检材的适应性与一致性、种属特异性、混合样本等9个方面对GoldeneyeTM20A试剂盒进行测试。结果阳性DNA样本分型正确,内标和等位基因分型标准物符合要求;等位基因间的均衡性≥83%,同一荧光标记基因座间的均衡性≥55%,不同标记物间的均衡性≥52%;0.125ng DNA阳性样本可检出全部STR基因座分型,不同批次间和反复冻融后试剂盒测试可以获得正确分型,对降解检材和混有抑制剂的样本等具有一定的耐受性,能对案件中多种检材进行分型且分型结果一致,具有一定的种属特异性和混合DNA样本检测能力。结论国产GoldeneyeTM 20A试剂盒可用于法庭科学实际检案与建库。     

Drug intelligence based on MDMA tablets data: 2. Physical characteristics profiling

One of the tasks of the European project entitled “Collaborative Harmonisation of Methods for Profiling of Amphetamine Type Stimulants” (CHAMP) funded by the sixth framework programme of the European Commission was to develop a harmonised methodology for MDMA profiling and the creation of a common database in a drug intelligence perspective. Part I was dedicated to the analysis of organic impurities formed during synthesis in order to investigate traffic tendencies and highlight potential links between samples, whereas this part focuses on physical characteristics of the MDMA tablets. Diameter, thickness, weight and score were demonstrated to be reliable and relevant features in this drug intelligence perspective. Distributions of samples coming from the same post-tabletting batch (post-TB) and samples coming from different post-TB were very well discriminated by using the squared Euclidean or the Manhattan distance on standardised data. Our findings demonstrated the possibility to discriminate between MDMA samples issued from different post-TB and to find out links between samples coming from a same post-TB. Furthermore, the hypothesis that most of the MDMA samples found on the international market come from the same countries was supported.     

Drug intelligence based on MDMA tablets data: 2. Physical characteristics profiling

One of the tasks of the European project entitled “Collaborative Harmonisation of Methods for Profiling of Amphetamine Type Stimulants” (CHAMP) funded by the sixth framework programme of the European Commission was to develop a harmonised methodology for MDMA profiling and the creation of a common database in a drug intelligence perspective. Part I was dedicated to the analysis of organic impurities formed during synthesis in order to investigate traffic tendencies and highlight potential links between samples, whereas this part focuses on physical characteristics of the MDMA tablets. Diameter, thickness, weight and score were demonstrated to be reliable and relevant features in this drug intelligence perspective. Distributions of samples coming from the same post-tabletting batch (post-TB) and samples coming from different post-TB were very well discriminated by using the squared Euclidean or the Manhattan distance on standardised data. Our findings demonstrated the possibility to discriminate between MDMA samples issued from different post-TB and to find out links between samples coming from a same post-TB. Furthermore, the hypothesis that most of the MDMA samples found on the international market come from the same countries was supported.     

Comparative analysis of 1-phenyl-2-propanone (P2P), an amphetamine-type stimulant precursor, using stable isotope ratio mass spectrometry: Presented in part as a poster at the 2nd meeting of the Joint European Stable Isotope User Meeting (JESIUM), Giens, France, September 2008

The isotope ratios of amphetamine type stimulants (ATS) depend as well on the precursor as the synthetic pathway. For clandestine production of amphetamine and methamphetamine, 1-phenyl-2-propanone (P2P, benzylmethylketone) is a commonly used precursor.Our aim was to determine the variation of the isotope ratios within precursor samples of one manufacturer and to compare seized samples of unknown sources to these values. δ¹³C_V-PDB, δ²H_V-SMOW and δ¹⁸O_V-SMOW isotope ratios were determined using elemental analysis (EA) and gas chromatography (GC) coupled to an isotope ratio mass spectrometer (IRMS). The comparison of all seized samples to the data of the samples of one manufacturer revealed considerable differences. The results show that IRMS provides a high potential in differentiating between precursors from different manufacturers for the clandestine production of ATS and identifying corresponding sources.     

Development of a fast, simple profiling method for sample screening using high resolution melting (HRM) of STRs

A screening assay has been developed to provide preliminary individualization of crime scene samples thus eliminating expensive, time-consuming short tandem repeat (STR) profiling of nonprobative samples. High resolution melting performed in a real-time PCR instrument is used to detect the slight melting differences between the length and sequence variations of 22 forensic STRs. Three STRs (vWA, D18S51, THO1) were chosen to develop an assay which was optimized for Mg++ concentration, annealing/extension time/temperature, assay volume, and bovine serum albumin addition. The assay was tested for reproducibility, uniformity for genotype, melting profile consistency, effects of inhibitors, and mixture effects. The assay could be used to determine DNA concentration when a standard curve is run simultaneously. Calculations of costs show that the assay can save significant time and money for a crime with many samples or suspects.     

SEM-EDS analysis and discrimination of forensic soil

Soils vary among different areas, and have some characteristics because of the natural effects and transfers made by human and other living beings in time. So that forensic examination of soil is not only concerned with the analysis of naturally occurring rocks, minerals, vegetation, and animal matter. It also includes the detection of such manufactured materials such as ions from synthetic fertilizers and from different environments (e.g., nitrate, phosphate, and sulfate) as environmental artifacts (e.g., lead or objects as glass, paint chips, asphalt, brick fragments, and cinders) whose presence may impart soil with characteristics that will make it unique to a particular location. Many screening and analytical methods have been applied for determining the characteristics which differentiate and discriminate the forensic soil samples but none of them easily standardized. Some of the methods that applied in forensic laboratories in forensic soil discrimination are the color comparison of the normal air-dried (dehumidified) and overheated soil samples, macroscopic observation, and low-power stereo-microscopic observation, determination of anionic composition by capillary electrophoresis (CE), and the elemental composition by scanning electron microscope (SEM)-energy dispersive X-ray spectrometer (EDS) and other high sensitivity techniques. The objective of this study was to show the effect of the application of 9 tonnes/cm2 pressure on the elemental compositions obtained by SEM-EDS technique and comparing the discrimination power of the pressed-homogenized and not homogenized forensic soil samples. For this purpose soil samples from 17 different locations of Istanbul were collected. Aliquots of the well mixed samples were dried in an oven at 110-120 degrees C and sieved by using 0.5 mm sieve and then the undersieve fraction(<0.5 mm) of these samples put on an adhesive tape placed on a stub. About 100-150 mg aliquots of dried, sieved samples were pressed under 9 tonnes/cm2 pressure by KBr disk preparation apparatus of an infrared spectrophotometer. Surfaces of the randomized particles and the pressed disks of the soil samples were scanned and the elemental compositions were determined with scanning electron microscope JEO-JSM-5600 equipped with an energy dispersive X-ray spectrometer OXFORD Link-ISIS-300. The samples from top of the sieves were examined with stereo-microscope equipped with JVC-TK-128DE color video camera and JVC-GV-PT2, digital video printer. Natural and artificial materials that have characteristic features were identified. Then for additional confirmation all soil samples were dried at 120 degrees C and over 780 degrees C and their colors compared. We concluded that pressing the whole sieved soil samples under 9 tonnes/cm2 pressure results in smashing over the harder particles into the softer matrix and results in homogenization of the soil sample. The elemental compositions of these samples obtained by SEM-EDS with 10-fold less standard deviation (S.D.) values and so that with more reproducibility and discrimination power.