ENFSI proficiency test program on identification of GSR by SEM/EDX

Within the framework of the ENFSI Expert Working Group "Firearms," a proficiency test on the detection and identification of GSR by SEM/EDX was organized and performed. The test material was designed by the Bundeskriminalamt and manufactured to order by an external company for SEM accessories. The participating laboratories were requested to determine the total number of PbSbBa-containing particles on the test samples following their own laboratory specific methods of automated GSR particle search and detection by SEM/EDX. Two similar samples with synthetic GSR particles were dispatched to all participants in order to gain additional information on systematic errors within the obtained results (split-level study), whereas one sample was supplied only with PbSbBa particles, and the second one was additionally contaminated with some environmental particles. This report summarizes the results of the study as well as a statistical evaluation and comparison with previous studies.     

GSR2005--continuity of the ENFSI proficiency test on identification of GSR by SEM/EDX.

Within the framework of the ENFSI Expert Working Group "Firearms" a proficiency test on the detection and identification of GSR by energy-dispersive scanning electron microanalysis (SEM/EDX) is carried out in a 2 years term. The latest test was performed in 2005/2006 and was denoted as GSR2005. Seventy-five laboratories from 28 countries participated in this proficiency test and submitted in total 83 independent data-sets. The participating laboratories were requested to determine the total number of PbSbBa containing particles on a synthetic test sample following their own laboratory specific methods of automated GSR particle search and detection by SEM/EDX. Furthermore size and position of the detected particles had to be reported by the laboratories and were evaluated statistically. The results were compiled by means of z-scores according to the IUPAC and EURACHEM guidelines-assessing individual laboratory achievements (inter-laboratory) as well as intra-laboratory performance-and were compared to the results of the previous proficiency test run GSR2003 (1). The comparison shows that there is a noticeable improvement in the method's detection capability.     

GSR2005—Continuity of the ENFSI Proficiency Test on Identification of GSR by SEM/EDX

Abstract:  Within the framework of the ENFSI Expert Working Group "Firearms" a proficiency test on the detection and identification of GSR by energy-dispersive scanning electron microanalysis (SEM/EDX) is carried out in a 2 years term. The latest test was performed in 2005/2006 and was denoted as GSR2005 . Seventy-five laboratories from 28 countries participated in this proficiency test and submitted in total 83 independent data-sets. The participating laboratories were requested to determine the total number of PbSbBa containing particles on a synthetic test sample following their own laboratory specific methods of automated GSR particle search and detection by SEM/EDX. Furthermore size and position of the detected particles had to be reported by the laboratories and were evaluated statistically. The results were compiled by means of z -scores according to the IUPAC and EURACHEM guidelines—assessing individual laboratory achievements (inter-laboratory) as well as intra-laboratory performance—and were compared to the results of the previous proficiency test run GSR2003 ( 1 ). The comparison shows that there is a noticeable improvement in the method's detection capability.     

Identify the injury implements by SEM/EDX and ICP-AES

The forensic investigator is frequently confronted with the discrimination and deduction of injury implements, which is one of the most important physical testimonies in courts. The usual method used in actual cases is from points of morphology. In the forensic discrimination of injury implements, such as metal implements, the analysis and comparison of elements are expected to provide excellent results, and simultaneous multi-elemental analysis is required to analyze various kinds of elements. This study was designed to establish discrimination and deduction of metal injury implements by scanning electron microscope/energy disperse X-ray microanalyzer (SEM/EDX) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Examined metal particles in five wounds made on the skin of domestic pigs, respectively, using Cu-Zn or Cr-Ni coated and carbon steel kitchen implements by EDX. For carbon steel kitchen implements, analyzed five samples from the back and blade separately in the contents and varieties of elements by ICP-AES. In the wounds by the coated implements, the special particles only containing Cu, Zn or Cr, Ni were found. In the wounds by carbon steel kitchen implements, the particles containing Fe, Cr, Si or Fe, Mn, Si were found. The differences of contents of elements between the back and blade was no significant except No. 5 for carbon steel kitchen implements, and the significant differences of elements exited in Cr, Mn, Si, Cu, Mo among the stainless kitchen knives, Mn, Si among the other kitchen implements and for the blade of No. 5 knife, relative standard deviations (R.S.D.s) were significantly different in Mn, Si, Mo, Ti, S, P, Ni. Using EDX to examine the particles in wounds can deduce the categories of metal injury implements, and we can still deduce the different implements in the same category by ICP-AES.     

Trajectory Reconstruction Through Analysis of Trace Evidence in Bullet–Intermediate Target Interaction by SEM/EDX

Abstract:  A young male was shot to death by a police officer with a Chinese Type 64 7.62 mm pistol when he was dealing with an aggravated assault arising from a traffic accident. By using scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDX), trace deposits on the discharged bullet and the intermediate target, i.e., a concrete telegraph pole at the scene, were identified to be from each other. The result demonstrated the bullet causing the death ricocheted from the concrete telegraph pole before striking the victim, thus indicating the incident was accidental. The case report illustrates the evidential value of trace materials derived, respectively, from discharged bullets and intermediate targets in bullet–intermediate target interaction for trajectory reconstruction. In addition, it indicates that the SEM/EDX method with its nondestructive nature, compared to other methods, may be more helpful in certain situations in determining the origins of trace evidentially valuable deposits on substrates.     

Is there a real danger of concealing gunshot residue (GSR) particles by skin debris using the tape-lift method for sampling GSR from hands?

Experiments were carried out to assess the danger of concealing GSR particles by skin debris using the tape-lift method for sampling GSR from hands. Thirty discrete spherical particles (from GSR and from the debris of oxygen cutting of steel) sized from 8 to 30 microns were mounted on a double-side adhesive coated stubs in known locations using a stereomicroscope. These stubs were then used for dabbing hands 50 times. Some of the particles or parts thereof were covered by skin flakes, however, all particles could be detected using the backscattered electron image (BEI) in the scanning electron microscope (SEM). Also, all could be identified by the energy dispersive X-ray spectroscopy (EDX).     

Scanning Electron Microscopy–Energy‐Dispersive X‐Ray (SEM/EDX): A Rapid Diagnostic Tool to Aid the Identification of Burnt Bone and Contested Cremains

This study investigates the use of Scanning electron microscopy–energy‐dispersive X‐ray (SEM‐EDX) as a diagnostic tool for the determination of the osseous origin of samples subjected to different temperatures. Sheep (Ovis aries) ribs of two experimental groups (fleshed and defleshed) were burned at temperatures of between 100°C and 1100°C in 100°C increments and subsequently analyzed with the SEM‐EDX to determine the atomic percentage of present elements. Three‐factor ANOVA analysis showed that neither the exposure temperature, nor whether the burning occurred with or without soft tissue present had any significant influence on the bone's overall elemental makeup (p > 0.05). The Ca/P ratio remained in the osseous typical range of between 1.6 and 2.58 in all analyzed samples. This demonstrates that even faced with high temperatures, the overall gross elemental content and atomic percentage of elements in bone remain stable, creating a unique “fingerprint” for osseous material, even after exposure to extreme conditions.     

扫描电子显微镜/能谱法对铊盐的检验

目的建立投毒案件中铊元素的一种快速定性检验方法。方法：在扫描电子显微镜下用背散射电子探头（BSE）观察处理后的样品,观察图像中根据元素衬度差异挑选出可能含铊元素的区域,用能谱仪做该区域的元素定性检验。结果能谱分析仪可以很快对各种元素做出准确的定性检验。结论扫描电子显微镜/能谱法对疑似铊中毒案的检验快速、灵敏、准确。     

Erroneous gender identification by the amelogenin sex test

Human gender identification, based on the amelogenin gene, has important applications in forensic casework, prenatal diagnosis, DNA databasing, and blood sample storage. However, we report on the first known case, in the Israeli population, of an amelogenin sex test failure on a phenotypically normal male. He was typed as a female by both the AmpFlSTR SGM plus and GenePrint kits. Subsequent, karyotyping of the soldier's blood sample showed no abnormalities. These results suggest that the determination of sex, based on the amelogenin test, should be interpreted cautiously.     

蓝色电工胶带的扫描电镜／能谱法检验

目的研究不同品牌蓝色电工胶带的检验方法。方法利用扫描电镜／能谱法对蓝色电工胶带进行检验。结果11个厂家生产的15种品牌的蓝色电工胶带组成的105组样品对有104组可以区分,区分率达到99．0％。结论扫描电镜／能谱法能够区分绝大多数蓝色电工胶带,该方法具有操作简便、快速、结果准确的优点,能够用于同色电工胶带的鉴别。     

A morphological study of human hair tips by scanning electronic microscope (SEM)

Morphological characteristics of human hair tip was studied by SEM. It was concluded that human hair tips could be classified into eight types. The tip formation, distribution and changes after being trimmed were explored. This study can be used in the mechanism research of human hair growth and the forensic hair examination.     

人体毛发尖部形态的扫描电镜研究

采用扫描电镜观察人体毛发尖部微观形态特征，总结归纳了人体主要几个部位毛发尖部形态的八种类型，探讨各类毛尖形状其形成的可能条件、分布的规律性以及修剪后端部的变化情况，为研究人体毛发生长机理、法庭科学的毛发鉴定工作提供依据。     

The 1998-1999 collaborative exercises and proficiency testing program on DNA typing of the Spanish and Portuguese Working Group of the International Society for Forensic Genetics (GEP-ISFG)

A total of 28 laboratories (labs) submitted results for the 1998 collaborative exercise and the proficiency testing program of the Spanish and Portuguese Working Group of the International Society for Forensic Genetics (GEP-ISFG) group. This number increased to 46 labs in 1999. Six bloodstains were submitted, each one with 200 microl soaked in cotton except the sample no. 6 submitted for DNA quantification which had 2 microl. One of the samples was a mixed stain. A paternity testing case and a criminal case in the 1998 trial (GEP'98) and two paternity testing cases in 1999 (GEP'99) were included and the statistical evaluation of the evidence was requested in both cases. In the GEP'99 trial, a theoretical paternity testing case was included. A total of 52 DNA genetic markers were used by the participants in the GEP'98 trial, which increased to 101 in GEP'99. Despite this increasing number of participating labs, results remained quite satisfactory. All the labs used PCR-based DNA polymorphisms with an increasing number of markers, obtaining good results. SLPs were used by a decreasing number of labs but the results indicated a good level of expertise despite the different protocols used.Good results were also obtained for mtDNA despite the difficulties presented by the samples due to the presence of length heteroplasmy in some samples in both trials. The detection of heteroplasmy should, however, be improved.Similar conclusions were reached for both, the paternity and the criminal case by all the labs. Common methodologies for the statistical evaluation of the paternity case were used and the paternity index and the probability of paternity (with an a priori value of 0.5) reported by most of the labs. Also, a great uniformity was found in the evaluation of the criminal case despite the lack of a specific hypothesis in the design of the exercise. Some errors in statistical programs or in calculations were detected in a theoretical paternity case included in the GEP'99 trial for statistical analysis.     

Characterization of pyrotechnic reaction residue particles by SEM/EDS

Today the method commonly used for detecting gunshot residue is through the combined use of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In recent years, this same methodology began to find use in detecting and characterizing pyrotechnic reaction residue (PRR) particles whether produced by explosion or burning. This is accomplished by collecting particulate samples from a surface in the immediate area of the pyrotechnic reaction. Suspect PRR particles are identified by their morphology (typically 1 to 20 microm spheroidal particles) using an SEM; then they are analyzed for the elements they contain using X-ray EDS. This can help to identify the general type of pyrotechnic composition involved.     

大鼠溺死后气管纤毛变化的扫描电镜观察

应用扫描电镜对大鼠溺死后不同时间气管纤毛病理变化进行了观察，发现溺死大鼠气管纤毛局部紊乱，杯状细胞顶端开口增多，纤毛表面粘附有较多的絮网状结构．随死后时间延长，纤毛出现粘结、倒伏、结构破坏、消失等死后变化．结果表明，用扫描电镜观察上述变化有助于溺死死因诊断和死后经过时间的推断．     

Evaluation of prostate-specific antigen (PSA) membrane test assays for the forensic identification of seminal fluid.

Prostate specific antigen (PSA, also known as p30), a glycoprotein produced by the prostatic gland and secreted into seminal plasma, is a marker used for demonstrating the presence of seminal fluid. Methods for the detection of PSA include Ouchterlony double diffusion, crossover electrophoresis, rocket immuno-electrophoresis, radial immunodiffusion, and ELISA. The extremely sensitive ELISA technique can detect PSA in concentrations as low as approximately 4 ng/mL. However, all these techniques are cumbersome and time consuming to perform in forensic laboratories, especially when only a few samples per week are processed. Various membrane tests are currently used in clinical settings to screen a patient's serum for the presence of PSA at levels greater than 4 ng/mL. In this study we evaluated three immunochromatographic PSA membrane tests by analyzing semen stains stored at room temperature for up to 30 years, post-coital vaginal swabs taken at different time after intercourse, semen-free vaginal swabs, and various female and male body fluids, including urine. The data demonstrate that PSA membrane test assays offer the same sensitivity as ELISA-based tests and provide a rapid approach for the forensic identification of seminal fluid. Furthermore, when the supernatant from a DNA extraction is used for the assay, there is essentially no DNA consumption for determining the presence of PSA in a forensic sample.     

Particle Analysis for the Detection of Gunshot Residue (GSR) in Nasal Samples Using Scanning Laser Ablation and Inductively Coupled Plasma-Mass Spectrometry (SLA-ICPMS)

Currently, aluminum stub with carbon adhesive devices are used to collect inorganic gunshot residues (GSR) from the hands of a shooter. In an ideal shooting case, the gunshot particles do not persist for more than 2 h in the hands of the shooter, provided that the hands have not been washed. However, for forensic analysis and inference, the extended persistence of GSR would be desirable. This study investigates a novel GSR sampling and detection protocol. Sampling was performed in the nostrils using swab devices impregnated in ethylenediaminetetraacetic acid (EDTA). The GSRs persisted for longer periods in nasal mucus than on the hands, and particles were detected 6 h after shooting occurred. The analytical determination was conducted by scanning laser ablation-inductively coupled plasma-mass spectrometry (SLA-ICPMS) which enable the identification of the number of particles and their elemental composition. Seventeen isotope signals corresponding to ¹³C, ²⁰⁵Tl and 15 analytes that are usually associated with the composition of GSR residues were monitored: ²⁷Al, ²⁹Si, ³¹P, ³³S, ³⁵Cl, ³⁹K, ⁴⁴Ca, ⁵⁷Fe, ⁶⁰Ni, ⁶³Cu, ⁶⁶Zn, ¹¹⁸Sn, ¹²¹Sb, ¹³⁷Ba, and ²⁰⁸Pb. The SLA technique enabled the reduction of the swab analysis time to 40 min. The effectiveness of this methodology was evaluated with two types of firearms: a pistol and a shotgun. The results indicated that the methodology proposed for the analysis of the nasal GSR was effective and that it can improve or complement the forensic analyses and inferences presented in a court.     

Individual identification from semen by the deoxyribonucleic acid (DNA) fingerprint technique

For individual identification from semen, the deoxyribonucleic acid (DNA) fingerprint technique was used. In a blind trial, we succeeded in determining the semen donors among several volunteers comparing the DNA fingerprints of the blood and semen samples, respectively. Thereafter, we examined semen in a condom left beside a naked female dead body. The DNA fingerprint of the semen was recognized to be identical to that of the blood from a suspected man arrested later. This is the first report that the DNA fingerprint technique was practically used in a criminal investigation in Japan.