Most of the automotive companies use cast iron for their engine blocks. Restoration of obliterated number on these iron surfaces by chemical etching is known to be quite difficult. Heating of the obliterated surface using oxyacetylene flame is an alternative recovery treatment suggested in literature and used in practice. However chemical etching has been established to be the most sensitive technique for detection of metal deformation present under stamped serial numbers. Hence, the current work investigated the suitability of some common etchants on cast iron surfaces with a view to determining the most suitable one for revealing the obliterated marks. The reagents tested were mostly copper containing Fry's reagent and its modifications. Two cast iron engine blocks (3.29%C and 3.1%C) of two cars--a Proton Saga and a Toyota--were utilized for the experiments. The engine blocks were cut into several small plates and each plate was stamped with some numerical characters at 8 kN load using Instron Table Mounted Universal Testing Machine. The depth of stamping impression varied between 0.2 mm and 0.3 mm. The stamped number was completely ground off manually using a metal file. The grounded surface was then polished smooth using emery papers and etched with a few selected reagents mostly by swabbing. Experimental results showed that a modified Fry's composition consisting of 4 5g CuCl(2), 100 mL HCl, and 180 mL H(2)O restored the number with better contrast at a reasonably shorter time. The above reagent is a slightly modified form of one of the Fry's original compositions--45 g CuCl(2), 180 mL HCl, and 100 mL H(2)O. Quite importantly the proposed reagent restored the original stamped numbers of both Proton and Toyota cars and also a Mitsubishi car that had been obliterated. The most widely used Fry's composition (90 g CuCl(2), 120 mL HCl and 100 mL H(2)O), although recovered the obliterated number, did not cause the desired contrast.
Mitragyna speciosa, a native plant of Thailand and Malaysia known as 'ketum', is a plant of considerable interest. It exhibits strong antinociceptive effect and yet, acts like a psychostimulant. Due to the affordability and its ease of availability, the abuse of this plant as a substitute for other banned narcotics has become a major concern in many societies. In countries such as Thailand, Myanmar, Australia and Malaysia, the use of ketum is illegal. However, for a person to be charged for possessing or selling ketum, a reliable analytical method is needed in order to detect and identify the plant and its products. Mitragynine is the major alkaloid of ketum. This compound manifests its antinociceptive effects by acting on the opioid receptors. Since M. speciosa contain large quantity of mitragynine and it is exclusive to the species, the present analytical method is developed and validated for the purpose of screening ketum products based on this unique compound as the analytical marker. The method uses a HPLC-DAD system with Inertsil C8 (4.6 mm × 150 mm, 5 μm) as the column and a mixture of acetonitrile and formic acid, 50:50 (v/v), as the mobile phase. This method not only detects mitragynine, it can also be used to quantify the amount of mitragynine in the sample. The limit of detection is 0.25 μg/ml, while the limit of quantification is 0.50 μg/ml. The method is quick, simple and reliable with an accuracy of 97.27-101.74% and coefficient of variations of between 0.91 and 3.96%. The method has been tested and found suitable for the identification and quantification of mitragynine in dried plants, a variety of ketum extracts, as well as ketum drink obtained from the market.
The ability to objectify ballistic evidence is a challenge faced by firearms examiners around the world. A number of researchers are trying to improve bullet-identification systems to address deficiencies detailed within the National Academy of Science report (2009). More recently focus has turned to making use of more sophisticated imaging modalities to view entire regions of the projectile and the development of automated systems for the comparison of the topographical surfaces recorded. Projectiles from a newly bought air pistol with 0.177 calibre pellets (unjacketed), fired series of 609 pellets were examined using an optical microscope. A mathematical methodology was developed to pre-process the resultant topographical maps generating point data for comparison, analysed using the principal component analysis (PCA). In most cases limited to reasonable success was achieved. The objective method still requires an operator to identify the Land Engraved Areas to be scanned, however the mathematical alignments were objectively achieved. The PCA results illustrated that the striation marks were neither exclusive nor specific to the LEA regions but rather crossed over regions. This study also proves that a single weapon does not necessarily leave identical marks of projectiles on its surface.
Evidence in crime scenes available in the form of biological stains which cannot be visualized during naked eye examination can be detected by imaging their fluorescence using a combination of excitation lights and suitable filters. These combinations selectively allow the passage of fluorescence light emitted from the targeted stains. However, interference from the fluorescence generated by many of the surface materials bearing the stains often renders it difficult to visualize the stains during forensic photography. This report describes the use of background correction algorithm (BCA) to enhance the visibility of seminal stain, a biological evidence that fluoresces. While earlier reports described the use of narrow band-pass filters for other fluorescing evidences, here, we utilize BCA to enhance images captured using commonly available colour filters, yellow, orange and red. Mean-based contrast adjustment was incorporated into BCA to adjust the background brightness for achieving similarity of images' background appearance, a crucial step for ensuring success while implementing BCA. Experiment results demonstrated the effectiveness of our proposed colour filters' approach using the improved BCA in enhancing the visibility of seminal stains in varying dilutions on selected surfaces.
Sex estimation is used in forensic anthropology to assist the identification of individual remains. However, the estimation techniques tend to be unique and applicable only to a certain population. This paper analyzed sex estimation on living individual child below 19 years old using the length of 19 bones of left hand applied for three classification techniques, which were Discriminant Function Analysis (DFA), Support Vector Machine (SVM) and Artificial Neural Network (ANN) multilayer perceptron. These techniques were carried out on X-ray images of the left hand taken from an Asian population data set. All the 19 bones of the left hand were measured using Free Image software, and all the techniques were performed using MATLAB. The group of age "16-19" years old and "7-9" years old were the groups that could be used for sex estimation with as their average of accuracy percentage was above 80%. ANN model was the best classification technique with the highest average of accuracy percentage in the two groups of age compared to other classification techniques. The results show that each classification technique has the best accuracy percentage on each different group of age.
Establishing identification during skull-photo superimposition relies on correlating the salient morphological features of an unidentified skull with those of a face-image of a suspected dead individual using image overlay processes. Technical progression in the process of overlay has included the incorporation of video cameras, image-mixing devices and software that enables real-time vision-mixing. Conceptual transitions occur in the superimposition methods that involve 'life-size' images, that achieve orientation of the skull to the posture of the face in the photograph and that assess the extent of match. A recent report on the reliability of identification using the superimposition method adopted the currently prevalent methods and suggested an increased rate of failures when skulls were compared with related and unrelated face images. The reported reduction in the reliability of the superimposition method prompted a review of the transition in the concepts that are involved in skull-photo superimposition. The prevalent popular methods for visualizing the superimposed images at less than 'life-size', overlaying skull-face images by relying on the cranial and facial landmarks in the frontal plane when orienting the skull for matching and evaluating the match on a morphological basis by relying on mix-mode alone are the major departures in the methodology that may have reduced the identification reliability. The need to reassess the reliability of the method that incorporates the concepts which have been considered appropriate by the practitioners is stressed.
Scuttle flies of genus Puliciphora Dahl (Diptera: Phoridae) are recorded for the first time in Malaysia from rabbit carcasses placed in concealed environments. They consist of Puliciphora borinquenensis Wheeler ♂♀, Puliciphora obtecta Meijere ♀ and Puliciphora beckeri Meijere ♀. All species were obtained from rabbit carcasses in used luggage and garbage bin placed at Forensic Science Simulation Site, Universiti Kebangsaan Malaysia, Bangi, Selangor. The specimens were collected from the carcasses using a modified Malaise trap, an entomological aspirator and preserved in 70% ethanol. This report expands the geographical distributions of these species and their microhabitat, suggests its possible important role in forensic entomology.
A brief survey to assess the sensitivity and efficacy of some common etching reagents for revealing obliterated engraved marks on Al-Si alloy surfaces is presented. Experimental observations have recommended use of alternate swabbing of 10% NaOH and 10% HNO(3) on the obliterated surfaces for obtaining the desired results. The NaOH etchant responsible for bringing back the original marks resulted in the deposition of some dark coating that has masked the recovered marks. The coating had been well removed by dissolving it in HNO(3) containing 10-20% acid. However, the above etching procedure was not effective on aluminium (99% purity) and Al-Zn-Mg-Cu alloy surfaces. Also the two reagents (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH suggested earlier for high strength Al-Zn-Mg-Cu alloys  were quite ineffective on Al-Si alloys. Thus different aluminium alloys needed different etching treatments for successfully restoring the obliterated marks. Al-Si alloys used in casting find wide applications especially in the manufacture of engine blocks of motor vehicles. Hence, the results presented in this paper are of much relevance in serial number restoration problems involving this alloy.
Insect larvae and adult insects found on human corpses provide important clues for the estimation of the postmortem interval (PMI). Among all necrophagous insects, flesh flies (Diptera: Sarcophagidae) are considered as carrion flies of forensic importance. DNA variations of 17 Malaysian, two Indonesian and one Japanese flesh fly species are analysed using the mitochondrial COI and COII. These two DNA regions were useful for identifying most species experimented. However, characterisation of the species was not sufficiently made in the case of Sarcophaga javanica. Seventeen Malaysian species of forensic importance were successfully clustered into distinct clades and grouped into the six species groups: peregrina, albiceps, dux, pattoni, princeps and ruficornis. These groups correspond with generic or subgeneric taxa of the subfamily Sarcophaginae: Boettcherisca, Parasarcophaga, Liosarcophaga, Sarcorohdendorfia-Lioproctia, Harpagophalla-Seniorwhitea and Liopygia. The genetic variations found in COI and COII can be applied not only to identify the species of forensic importance, but also to understand the taxonomic positions, generic or subgeneric status, of the sarcophagine species.
The fingerprints are very typical for a human being. The present study was undertaken to study the gender differences in fingerprint ridge density in Chinese and Malaysian population. The study done on 200 subjects (100 males and 100 females) of Chinese origin and 100 subjects (50 males and 50 females) of Malaysian origin revealed that significant gender differences occur in the finger ridge density. Fingerprint mean ridge density of 12 ridges/25 mm(2) or less is found to be more likely to be of males and a mean ridge count of more the 13 ridges/25 mm(2) is more likely of female origin in Chinese subjects. Fingerprint mean ridge density of 11 ridges/25 mm(2) or less is found to be more likely to be of males and a mean ridge count of more the 13 ridges/25 mm(2) is more likely of female origin in Malaysian subjects.
BACKGROUND: One of the most commonly used method for dental age assessment is the method reported by Demirjian and coworkers in 1973. It was later modified by Willems and coworkers whereby they “performed a weighted ANOVA” in order to adapt the scoring system.
AIM: To evaluate the applicability of Demirjian and Willems methods for dental age estimation for Malaysian children and to correlate the accuracy of the findings with the chronology of tooth development of premolars and second molars.
MATERIALS AND METHODS: A total of 991 dental panoramic radiographs of 5-15-year-old Malaysian children were included in the study. The mean Demirjian and Willems estimated ages were compared to the mean chronological age.
RESULTS: The mean chronological age of the sample was 10.1±2.8 and 9.9±3.0 years for males and females respectively. Using the Demirjian method, the mean estimated dental age was 10.8±2.9 years for males and 10.5±2.9 years for females. For Willems method, the mean estimated age was 10.3±2.8 years males and 10.0±3.0 years respectively.
CONCLUSIONS: Willems method was more applicable for estimating dental age for Malaysian children. Overestimation in Demirjian method could be due to advanced development of second bicuspids and molars.
The task of identifying firearms from forensic ballistics specimens is exacting in crime investigation since the last two decades. Every firearm, regardless of its size, make and model, has its own unique 'fingerprint'. These fingerprints transfer when a firearm is fired to the fired bullet and cartridge case. The components that are involved in producing these unique characteristics are the firing chamber, breech face, firing pin, ejector, extractor and the rifling of the barrel. These unique characteristics are the critical features in identifying firearms. It allows investigators to decide on which particular firearm that has fired the bullet. Traditionally the comparison of ballistic evidence has been a tedious and time-consuming process requiring highly skilled examiners. Therefore, the main objective of this study is the extraction and identification of suitable features from firing pin impression of cartridge case images for firearm recognition. Some previous studies have shown that firing pin impression of cartridge case is one of the most important characteristics used for identifying an individual firearm. In this study, data are gathered using 747 cartridge case images captured from five different pistols of type 9mm Parabellum Vektor SP1, made in South Africa. All the images of the cartridge cases are then segmented into three regions, forming three different set of images, i.e. firing pin impression image, centre of firing pin impression image and ring of firing pin impression image. Then geometric moments up to the sixth order were generated from each part of the images to form a set of numerical features. These 48 features were found to be significantly different using the MANOVA test. This high dimension of features is then reduced into only 11 significant features using correlation analysis. Classification results using cross-validation under discriminant analysis show that 96.7% of the images were classified correctly. These results demonstrate the value of geometric moments technique for producing a set of numerical features, based on which the identification of firearms are made.
Restoration of obliterated engraved marks on high strength Al-Zn-Mg-Cu alloy (AA7010) surfaces by etching technique was studied. The alloy surfaces were mechanically engraved with some identification marks using "Gravograph". The marks were then erased by removing the metal to different levels up to and below the depth of engraving. Five metallographic reagents were tested on the obliterated surfaces by etching. The following two methods (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH were found to be quite effective to reveal the obliterated marks. These two procedures were also able to show effectively the marks obliterated by over-engraving and centre punching. Of the two techniques immersion in phosphoric acid provided more contrast. Interestingly, alternate swabbing of 60% HCl and 40% NaOH presented itself to be the common reagent for restoration on pure aluminium as well as its alloy surfaces. This is evident from our own current experiments and those of earlier researchers [G. Peeler, S. Gutowski, H. Wrobel, G. Dower, The restoration of impressed characters on aluminium alloy motor cycle frames, J. Forensic Ident. 58 (1) (2008) 27-32; M. Izhar M. Baharum, R. Kuppuswamy, A.A. Rahman, Restoration of engraved marks on aluminium surfaces by etching technique, Forensic Sci. Int. 177 (2008) 221-227]. The findings have assumed importance as engines and chassis of cars and frames of firearms are currently made of high strength aluminium alloys and recovery on these surfaces by current methods is not satisfactory.
In Penang, Malaysia, the Oriental and Afrotropical Megaselia curtineura (Brues) and the Oriental and Japanese Megaselia spiracularis Schmitz are reported from human corpses, these being the first reports of these species in such forensic cases.
The influence of rain and malathion on the initial oviposition as well as development of blowfly species infesting rabbit carcasses decomposing in sunlit and shaded habitats were studied over a period of 1 year in Kelantan, Malaysia. Chrysomya megacephala (Fabricius) was the most dominant species that infested the carcasses, followed by Chrysomya rufifacies (Macquart). In general, rain, depending on its intensity, delayed initial oviposition by 1-2 days and prolonged the pupation period by 1-3 days. The presence of malathion in the carcasses delayed initial oviposition by 1-3 days and prolonged the pupation period by 2-3 days. These findings deserve consideration while estimating postmortem interval since rain is a commonplace occurrence in Malaysia and malathion is one of the common poisons as an agent for choice to commit suicide.
Chemical etching, which is the most sensitive method to recover obliterated serial numbers on metal surfaces, has been practised quite successfully in forensic science laboratories all over the world. A large number of etchants suitable for particular metal surfaces based on empirical studies is available in the literature. This article reviews the sensitivity and efficacy of some popular etchants for recovering obliterated marks on medium carbon steel (0.31% C with ferrite-pearlite microstructure) used in automobile parts. The experiments involved engraving these carbon steel plates with some alphanumeric characters using a computer controlled machine "Gravograph" and erasing them to several depths below the bottom of their engraving depth. Seven metallographic reagents of which most of them were copper containing compounds were chosen for etching. The erased plates were etched with every one of these etchants using swabbing method. The results have revealed that Fry's reagent comprising cupric chloride 90 g, hydrochloric acid 120 mL and water 100mL provided the necessary contrast and was concluded to be the most sensitive. The same reagent was recommended by earlier workers for revealing strain lines in steel surfaces. Earlier, another reagent containing 5 g copper sulphate, 60 mL water, 30 mL (conc.) ammonium hydroxide, and 60 mL (conc.) hydrochloric acid was proved to be more sensitive to restore erased marks on low carbon steel (0.1% C with ferrite-pearlite structure) [M.A.M. Zaili, R. Kuppuswamy, H. Harun, Restoration of engraved marks on steel surfaces by etching technique, Forensic Sci. Int. 171 (2007) 27-32]. Thus the sensitivity of the etching reagent on steel surfaces appeared to be dependent on the content of carbon in the steel.
A study has been made of the characteristics of restoration of obliterated engraved marks on aluminium surfaces by etching technique. By etching different reagents on 0.61mm thick sheets of aluminium (99wt%) on which some engraved marks had been erased to different depths it was found that the reagent 60% hydrochloric acid and 40% sodium hydroxide on alternate swabbing on the surfaces was found to be the most sensitive one for these metal surfaces. This reagent was able to restore marks in the above plates erased down to 0.04mm below the bottom of the engraving. The marks also presented excellent contrast with the background. This reagent was further experimented with similar aluminium surfaces, but of relatively greater thickness of 1.5mm. It was noticed that the recovery depth increased slightly to 0.06mm; this suggested the dependence of recovery depth on the thickness of the sheet metal. Further, the depth of restoration decreased in cases where the original number was erased and over which a new number was engraved; the latter results are similar to those of steel surfaces reported earlier [M.A.M. Zaili, R. Kuppuswamy, H. Harun, Restoration of engraved marks on steel surfaces by etching technique, Forensic Sci. Int. 171 (2007) 27-32].
It is known that restoration of erased engraved identification marks on the engine and the chassis of a car or on a firearm has low success rate. Unlike stamping, engraving on a metal surface leaves no pronounced, permanent subsurface deformation in the crystalline structure, also called dislocation that can be revealed by suitable methods. Hence, the current research work investigated whether metallographic reagents used in the restoration of stamp (compression) marks could be applied to recover engraved marks on steel surfaces and also to establish the sensitivity and effectiveness of some of these reagents for the restoration of the marks. Experiments were conducted by mechanically engraving alphanumeric characters on several steel plates using a computer controlled engraving machine called Gravograph. The markings were later erased from the above steel plates by removing the metal in stages of 0.01 mm through 0.04 mm below the bottom of the engraving. Several plates were thus prepared wherein each one had been abraded to a specific depth. Then eight metallographic reagents were tested on each one of the above erased plates using a swabbing technique. The results had shown that while most of the reagents were able to restore marks up to certain levels of erasure, the reagent 5 g copper sulphate, 60 ml water, 30 ml concentrated ammonium hydroxide and 60 ml concentrated hydrochloric acid restored marks erased to a depth of 0.04 mm below the engraving depth, thus presenting itself the most sensitive reagent. Quite significantly, the above reagent was also able to decipher successfully the original engraved marks that had been erased and engraved with a new number, or obliterated by centre punching. The results of this research work should benefit the forensic practitioners engaged in the serial number recovery on vehicles, firearms and other objects.
Detection of diatom frustules in bone marrow (diatom test) is used for diagnosing ante-mortem drowning where the usual signs of drowning are not present in dead bodies recovered from water. However, controversies over the reliability of diatom test results are continuing. There have been indications on the possibilities of diatoms entering into systemic circulation from atmospheric air, food and drink. While diatoms have been demonstrated in the gut content of edible marine forms such as shrimps and clams, the present study, for the first time, provides empirical evidence on the prevalence as well as abundance of diatom frustules in the samples of cooked non-vegetarian foodstuffs that impend human consumption in Kelantan, Malaysia. It is found that 50 g each of cleaned and cooked prawns and of clams impending human consumption contain about 8360 and 29,054 diatom frustules, respectively. A person accustomed to prawn and clam food would be ingesting an estimated 2 million diatoms in a single year. Considering the suggestion that detection of five diatom frustules in 10 g of bone marrow would suffice for concluding drowning as mode of death, and the fact that there is yet no proof that diatom frustules do not enter into the human systemic circulation through the digestive tract, the estimated number of diatom frustules routinely ingested acquires significance since entry of a few of such ingested frustules into the systemic circulation can lead to false positive test results. The findings of this research raise two important issues: first, population based routine food related diatom ingestion requires to be estimated, and, second, studies have to be initiated to categorically prove or disprove the possibility of entry of diatom frustules into the systemic circulation via the digestive tract.
The use of STR multiplexes with the incorporated gender marker Amelogenin is common practice in forensic DNA analysis. However, when a known male sample shows a dropout of the Amelogenin Y-allele, the STR system falsely genotypes it as a female. To date, our laboratory has observed 18 such cases: 12 from our Y-STR database and six from casework. A study on 980 male individuals in the Malaysian population using the AmpFlSTR Y-filer has revealed a distinct Y-chromosome haplotype associated with the Amelogenin nulls. Our results showed that whilst the Amelogenin nulls were noticeably absent among the Chinese, both the Indians and Malays exhibited such mutations at 3.2 and 0.6%, respectively. It was also found that the Amelogenin negative individuals predominantly belonged to the J2e lineage, suggesting the possibility of a common ancestor for at least some of these chromosomes. The null frequencies showed concordance with the data published in Chang et al. [Higher failures of Amelogenin sex test in an Indian population group, J. Forensic Sci. 48 (2003) 1309-1313] on a smaller Malaysian population of 338 males which used a Y-STR triplex. In the current study, apart from the absence of the Amelogenin Y-locus, a complete absence of the DYS458 locus in all the nulls was also observed. This study together with the 2003 study has indicated a similar deletion region exists on the Y(p)11.2 band in all the 18 Y-chromosomes. Using bioinformatics, this deletion has been mapped to a region of at least 1.13 Mb on the Y(p)11.2 encompassing the Amelogenin, MSY1 minisatellite and DYS458 locus. Further, the Y-filer haplotypes revealed an additional null at Y-GATA H4 in two of the Indian males presented here.