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West Jerusalem, Israel

Wiesner S.,Toolmarks and Materials Laboratory | Izraeli E.,Toolmarks and Materials Laboratory | Shor Y.,Toolmarks and Materials Laboratory | Domb A.,Israel Police H.Q.
Journal of Forensic Sciences

A method for lifting bloody footwear impressions using alginate casts and enhancing the lifted impressions with amido black is presented. On rough or dark substrates, background interferences may conceal significant details of footwear impressions. Illumination with alternative light sources and chemically enhancing the bloody footwear impressions may reveal additional details, but sometimes, lifting footwear impressions prior to enhancing is the only way to expose hidden details (by using blood reagents not adequate on the original). Several cast formulations were tested for lifting the footwear impressions. The best results were achieved using Aroma fine®. Enhancement of the footwear impressions was attempted with several reagents prior to lifting, during the casting process, and on the lifted footwear impressions. Applying amido black to footwear impressions lifted with alginate produced the sharpest and most detailed footwear impressions. Alginate castings followed by chemical enhancement with amido black may produce high-quality footwear impressions for comparison. © 2013 American Academy of Forensic Sciences. Source

Wiesner S.,Toolmarks and Materials Laboratory | Tsach T.,Toolmarks and Materials Laboratory | Belser C.,Forensisches Institute Zurich | Shor Y.,Toolmarks and Materials Laboratory
Journal of Forensic Sciences

Two-dimensional dust shoeprints are often of very high resolution and contain unique features. Lifting these prints in the most effective method may contribute much to preserving these fine details. A research was conducted by experts from Israel and Switzerland to compare gelatin lifters and electrostatic lifters for lifting shoeprints. Several substrates were chosen, and on each material a set of dry dust shoeprints was made. A set of wet prints was made on paper as well. The shoeprints were approximately of the same quality, and the only variable was the nature of the material. On substrates indifferent to the method used, the preferable sequence was tested. Gelatin lifter was superior on most substrates and for wet prints. The superior sequence for using both methods is electrostatic lifting followed by gelatin lifter. © 2010 American Academy of Forensic Sciences. Source

Izraeli E.S.,Toolmarks and Materials Laboratory | Tsach T.,Toolmarks and Materials Laboratory | Levin N.,Toolmarks and Materials Laboratory
X-Ray Spectrometry

Gunshot residue (GSR) analysis by scanning electron microscopy/energy dispersive x-ray spectrometry (SEM/EDX) is routinely performed in forensic science laboratories. At the end of 2011, a field emission gun (FEG)-SEM was installed at the authors' laboratory for this type of examination. Following the installation of the FEG-SEM, an extensive process was conducted, in order to determine the optimal operating parameters of this instrument for GSR analysis. Because the nature of synthetic GSR samples (such as the European Network of Forensic Science Institutes GSR2011 proficiency test sample) is significantly different from casework samples, it was decided not to use them for this purpose. Instead, a GSR casework sample, previously analyzed by tungsten-filament SEM as part of the laboratory's routine examinations, was selected. This sample was repeatedly analyzed (more than 200 times), under different operating conditions. The main parameters that were examined for the FEG-SEM were the electron source accelerating voltage, the backscattered electrons image acquisition time, the magnification, the backscattered electrons image resolution, and the energy-dispersive X-ray spectrometry acquisition time. The smallest detected feature was calculated by the software, based on the set image resolution and magnification. For each set of parameters, the detected GSR particles were recorded, in addition to the total number of detected particles and the time taken for the run. It was found that for a given smallest detected feature, the effective search conditions were higher magnification and lower number of pixels per line. The present work includes a detailed description of the optimization process and its results. The process utilized in this work is applicable for other laboratories conducting similar type of GSR analysis as well. © 2013 John Wiley & Sons, Ltd. Source

Cohen A.,Serious Crime Unit Mobile Laboratory | Grafit A.,Serious Crime Unit Mobile Laboratory | Cohen Y.,Latent Fingerprint Laboratory | Shor Y.,Toolmarks and Materials Laboratory | Wiesner S.,Toolmarks and Materials Laboratory
Journal of Forensic Identification

It was assumed that the high impact involved in car versus pedestrian accidents creates a microtexture imprint of the victim's clothing on the car. This texture was detected using a scanning electron microscope (SEM). Then small particle reagent (SPR) was successfully used to enhance fabric impressions. It is suggested that SPR fills in the three-dimensional imprint because of the physical characteristics and particle shape of MoS2, which is the active component of SPR, thereby enhancing the appearance of the impression. Source

Izraeli E.S.,Toolmarks and Materials Laboratory | Wiesner S.,Toolmarks and Materials Laboratory | Shor Y.,Toolmarks and Materials Laboratory
Journal of Forensic Identification

A simple, yet powerful method is described to aid the presentation of shoeprint comparisons in court. This method uses Adobe Photoshop Elements or other similar software for image processing and Microsoft PowerPoint for the presentation in court. The PowerPoint presentation will enable the expert to show the test impressions overlapping the prints, gradually change the opacity of the test impression on the print, and slightly move the test impression to imitate in great accuracy the comparison and evaluation process done in the laboratory. Source

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