Volume 15. Number 1
A Preliminary Study of Possible Role of Foot Impressions and Boot Marks as Means of Identification Among North Indian Individuals
Sandeep Garg ; Pankaj Chikkara ; Yogesh Kumar ; Abhishek Singh ; Shwetank Goel; Nand Kishore Singh ; Shelesh Goel ; Virender K Chhoker
Environmental Effects on Cartridge Case Primer Shear Marks
Stephanie M. Pollut ; Peter Diaczuk ; Carol J. Gambino ; Nicholas D. K. Petraco
Abstract： In order to address the scarcity of publications dealing with the comparison of cartridge cases subjected to environmental exposure, this pilot study investigated how the surface features of fired cartridge cases were affected when exposed to a moist environment over well defined periods of time. The primer shear marks of 25 (9mm) Remington 115 grain brass metal cartridge cases fired from a Glock 19 were examined. Five of these cases were not exposed (time = 0) to the environment so they could serve as control templates. All were viewed under a comparison microscope prior to exposure to confirm that the firearm was making reproducible marks on the primers. The cases were buried in a sun exposed forested plot in northeastern New Jersey (USA) during the summer months and analyzed at intervals of three, six, nine, and twelve weeks. The retrieved cases were examined once again with a comparison microscope. All buried cases were still capable of being matched with the unburied control cases despite some visible wear. Further examination with confocal microscopy was performed, in which 30 different surface parameters were measured. One-way Analysis of Variance (ANOVA) was applied to the mean surface parameters to determine if environmental exposure over time contributed significantly to observed variability (a rejection of the null hypothesis). All but one of the 30 parameter mean values met the 5% confidence level. The outlier value “Ssk” (p-value= 0.004), a height parameter which measures skewness of the height distribution, was further analyzed with the post hoc test Tukey HSD. It identified the comparison between the unburied case with the three week interval buried case as the source of the low probability (under 0.05).
Forensic Examination of Trace Intumescent Fire-Retardant Coating
Wen-Tung Lo ; Jin-Cherng Huang; Hsien-Hui Meng ; Yu-Ting Hsiung ; Wei-Tun ChangAbstract： During the investigations concerning uses of fire-retardant coating for fire safety or criminal purposes, it is often hard to visually distinguish between common architectural coatings and fire-retardant coatings on-site. This study aims to investigate trace intumescent fire-retardant coatings before and after a fire using micro Fourier transform infrared microspectroscopy (Micro-FTIR) and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS). Ten different types of intumescent fire-retardant coatings out of six brands were painted on plywood for testing according to the application standards of the manufacturers. The surface flammability test adopted was in accordance with Chinese National standards (CNS-6532). The resulting data indicated that after surface flammability test, those fire retardant coating samples could be differentiated from common architectural coatings by certain absorption peaks in IR spectra although the apparent spectral patterns of the two types of coatings were mostly similar except for two clear coatings,. The SEM/EDS approach was then used to analyze characteristic elements for further discrimination of the coatings with similar IR spectra. Thus, all the fire retardant coatings of different brands were essentially distinguishable from architectural coatings. As the second part of the study, efforts were made to estimate the mixing ratio of mixed fire retardant-architectural coatings, and develop a combined FTIR and SEM/EDS method to distinguish them. The results showed that the intumescence effects of these mixtures were insufficient and these mixtures left different degree of cracking on the wooden surface.
Chun-Chieh Chen ; Sheng-Meng Wang ; Te-Chuan Sun ; Chao-Kai Yang
Abstract： In crime scenes, relevant documents are sometimes torn or thrown into toilets or ditches to destroy evidence. At the scene of a fire, the environment becomes wet after firefighters extinguish the fire. Under these conditions, small particle reagent (SPR) can be successfully used to develop latent fingermarks on nonporous substrates. However, ninhydrin cannot be used to develop latent fingermarks on porous substrates under wet conditions because amino acids are soluble in water. To overcome this limitation, Oil Red O (ORO), a commonly used stain for detection of lipids in various biological fields, has been used to reveal the presence of residual water-insoluble components. Using bufferless ORO formulations, researchers have examined the effectiveness of sodium hydroxide, methanol, and different buffers. In the present study, we evaluated the effectiveness of a bufferless ORO technique for developing fingermarks on wet and special substrates, such as thermal paper and Bristol boards, in a wet environment in Taiwan. Bufferless ORO was used to develop latent fingermarks on glass, transparent plastic, thermal paper, A4 paper, and Bristol boards in a wet environment. Latent fingermarks successfully developed red ridges with a pink background on thermal paper and discolored the specimen. Bufferless ORO has been approved for use based on its environment- friendly features. Therefore, based on our analysis, the best way to develop latent fingermarks on regular wet paper was to use ninhydrin first, followed by ORO.
Verification of counterfeiting seal impressions made by photo-electric automatic engraving and photosetting methods
Abstract：Seals have been existed in Chinese history for over two thousand years and are still using today. There are numerous ways to create and use Chinese seals for fraudulent purposes. This paper presents an overview of the possible production ways of manufacturing seals using new technologies and tries to prove whether these production methods can eliminate the classical characteristics an examiner is looking for in the comparison of a reproduced seal impression to that of the original seal. It is proved that the conventional verification methods for Chinese se al impressions are still effective.