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.
Uniqueness being unprovable, it has recently been argued that individualization in forensic science is irrelevant and, probability, as applied for DNA profiles, should be applied for all identifications. Critiques against uniqueness have omitted physical matching, a realistic and tangible individualization that supports uniqueness. Describing case examples illustrating pattern matches including physical matching, it is indicated that individualizations are practically relevant for forensic science as they establish facts on a definitive basis providing firm leads benefitting criminal investigation. As a tenet of forensic identification, uniqueness forms a fundamental paradigm relevant for individualization. Evidence on the indeterministic and stochastic causal pathways of characteristics in patterns available in the related fields of science sufficiently supports the proposition of uniqueness. Characteristics involved in physical matching and matching achieved in patterned evidence existing in the state of nature are not events amenable for counting; instead these are ensemble of visible units occupying the entire pattern area stretching the probability of re-occurrence of a verisimilitude pattern into infinity offering epistemic support to uniqueness. Observational methods are as respectable as instrumental or statistical methods since they are capable of generating results that are tangible and obviously valid as in physical matching. Applying the probabilistic interpretation used for DNA profiles to the other patterns would be unbefitting since these two are disparate, the causal pathways of the events, the loci, in the manipulated DNA profiles being determinable. While uniqueness enables individualizations, it does not vouch for eliminating errors. Instead of dismissing uniqueness and individualization, accepting errors as human or system failures and seeking remedial measures would benefit forensic science practice and criminal investigation.
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.
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.
Considering that crimes against animals such as illegal killing and cruelty have been alarmingly increasing and since burning is one of the common ways for disposing cadavers, ability to estimate minimum postmortem interval (PMI) using entomological data merits consideration. Chrysomya megacephala and Chrysomya rufifacies are common necrophagous species recovered from cadavers in many countries including Malaysia. Specific studies focusing on the oviposition and developmental patterns of both species on cadavers manifesting different levels of burn as described by the Crow-Glassman Scale (CGS) remain scarce. In four replicates, rabbit carcasses were burned to CGS levels #1, #2 and #3 by varying the amount of petrol used and duration of burning. Oviposition by C. megacephala and C. rufifacies was delayed by one day in the case of carcasses burned to the CGS level #3 (p<0.05) when compared with that of controls. Such delay in oviposition was not observed in the CGS level #1 and #2 carcasses. No significant differences (p>0.05) in the duration of development were found between control and burned carcasses. These findings deserve consideration while estimating minimum PMI since burning as a mean for disposing animal and human cadavers is gaining popularity.
A research that tested the methods suitable for comparing ante- and post-mortem radiographic patterns of frontal sinuses concluded that superimposition should be followed as a stringent method for establishing individual identification. We verified the practical relevance of prescribing superimposition by superimposing ante- and post-mortem frontal sinus patterns recorded in case situations as well as simulated ante- and post-mortem of frontal sinus patterns recorded using archived skulls. For superimposition, the wipe facility available in the vision mixer was employed in addition to the mix mode. Ante- and post-mortem radiographic patterns that were available in two earlier cases were not superimposable. Related simulated ante- and post-mortem radiographic patterns of frontal sinuses are superimposable only when the skull that is initially oriented for recording the ante-mortem radiograph is retained in the same posture for recording the post-mortem radiograph also. Once the skull has been removed from the X-ray table, after recording the simulated ante-mortem radiograph, and repositioned for the simulated post-mortem radiograph, even when the intervening time is 1min, the sinus patterns in these radiographs are not superimposable. Superimposition cannot be used as a conditional requirement for side-by-side comparison of radiographic patterns of frontal sinuses.
Often cited reliability test on video superimposition method integrated scaling face-images in relation to skull-images, tragus-auditory meatus relationship in addition to exocanthion-Whitnall's tubercle relationship when orientating the skull-image and wipe mode imaging in addition to mix mode imaging when obtaining skull-face image overlay and evaluating the goodness of match. However, a report that found higher false positive matches in computer assisted superimposition method transited from the above foundational concepts and relied on images of unspecified sizes that are lesser than 'life-size', frontal plane landmarks in the skull- and face- images alone for orientating the skull-image and mix images alone for evaluating the goodness of match. Recently, arguing the use of 'life-size' images as 'archaic', the authors who tested the reliability in the computer assisted superimposition method have denied any method transition. This article describes that the use of images of unspecified sizes at lesser than 'life-size' eliminates the only possibility to quantify parameters during superimposition which alone enables dynamic skull orientation when overlaying a skull-image with a face-image in an anatomically acceptable orientation. The dynamic skull orientation process mandatorily requires aligning the tragus in the 2D face-image with the auditory meatus in the 3D skull-image for anatomically orientating the skull-image in relation to the posture in the face-image, a step not mentioned by the authors describing the computer assisted superimposition method. Furthermore, mere reliance on mix type images during image overlay eliminates the possibility to assess the relationship between the leading edges of the skull- and face-image outlines as also specific area match among the corresponding craniofacial organs during superimposition. Indicating the possibility of increased false positive matches as a consequence of the above method transitions, the need for testing the reliability in the superimposition method adopting concepts that are considered safe is stressed.
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.
Allele frequencies for the 15 STR loci in the AmpFlSTR Identifiler kit were determined and compared for the three main ethnic groups of the Malaysian population comprising 210 Malays, 219 Chinese and 209 Indians. Blood was placed on FTA paper and DNA was purified in-situ.
Currently, digital images and videos have high importance because they have become the main carriers of information. However, the relative ease of tampering with images and videos makes their authenticity untrustful. Digital image forensics addresses the problem of the authentication of images or their origins. One main branch of image forensics is passive image forgery detection. Images could be forged using different techniques, and the most common forgery is the copy-move, in which a region of an image is duplicated and placed elsewhere in the same image. Active techniques, such as watermarking, have been proposed to solve the image authenticity problem, but those techniques have limitations because they require human intervention or specially equipped cameras. To overcome these limitations, several passive authentication methods have been proposed. In contrast to active methods, passive methods do not require any previous information about the image, and they take advantage of specific detectable changes that forgeries can bring into the image. In this paper, we describe the current state-of-the-art of passive copy-move forgery detection methods. The key current issues in developing a robust copy-move forgery detector are then identified, and the trends of tackling those issues are addressed.
We have analyzed 16 Y-STR loci (DYS456, DYS389I, DYS390, DYS389II, DYS458, DYS19, DYS385a/b, DYS393, DYS391, DYS439, DYS635 or Y-GATA C4, DYS392, Y-GATA H4, DYS437, DYS438 and DYS448) from the non-recombining region of the human Y-chromosome in 980 male individuals from three main ethnic populations in Malaysia (Malay, Chinese, Indian) using the AmpFlSTR((R)) Y-filertrade mark (Applied Biosystems, Foster City, CA). The observed 17-loci haplotypes and the individual allele frequencies for each locus were estimated, whilst the locus diversity, haplotype diversity and discrimination capacity were calculated in the three ethnic populations. Analysis of molecular variance indicated that 88.7% of the haplotypic variation is found within population and 11.3% is between populations (fixation index F(ST)=0.113, p=0.000). This study has revealed Y-chromosomes with null alleles at several Y-loci, namely DYS458, DYS392, DYS389I, DYS389II, DYS439, DYS448 and Y-GATA H4; and several occurrences of duplications at the highly polymorphic DYS385 loci. Some of these deleted loci were in regions of the Y(q) arm that have been implicated in the occurrence of male infertility.
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.
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.
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 series of experiments was conducted by exposing negative film in brand new cameras of different make and model. The exposures were repeated at regular time intervals spread over a period of 2 years. The processed film negatives were studied under a stereomicroscope (10-40x) in transmitted illumination for the presence of the characterizing features on their four frame-edges. These features were then related to those present on the masking frame of the cameras by examining the latter in reflected light stereomicroscopy (10-40x). The purpose of the study was to determine the origin and permanence of the frame-edge-marks, and also the processes by which the marks may probably alter with time. The investigations have arrived at the following conclusions: (i) the edge-marks have originated principally from the imperfections received on the film mask from the manufacturing and also occasionally from the accumulated dirt, dust and fiber on the film mask over an extended time period. (ii) The edge profiles of the cameras have remained fixed over a considerable period of time so as to be of a valuable identification medium. (iii) The marks are found to be varying in nature even with those cameras manufactured at similar time. (iv) The influence of f/number and object distance has great effect in the recording of the frame-edge marks during exposure of the film. The above findings would serve as a useful addition to the technique of camera edge-mark comparisons.
A case is presented in which a camera recovered from a site of bomb blast was linked to some incriminating film negatives by the characteristic markings existing along a small portion of the edge of the film negatives.
Allele frequencies for the nine STRs genetic loci included in the AmpFlSTR Profiler kit were obtained from samples of unrelated individuals comprising 139-156 Malays, 149-153 Chinese and 132-135 Indians, residing in Malaysia.
Reliability, or repeatability, of permanent tooth staging techniques is usually expressed as Cohen's Kappa. This single value obscures information about the quantity and allocation of disagreements. In this study we assess and compare intra-observer reliability of permanent tooth staging techniques described by Nolla, Moorrees et al. and Demirjian et al. The sample was panoramic radiographs of healthy dental patients made up of 100 males and 100 females aged 6-15 years. All permanent teeth on the left side (excluding third molars) were scored twice. Weighted Kappa and percentage agreement were calculated. Results show Kappa values for all teeth combined as 0.918, 0.922 and 0.938 for Demirjian (number of teeth N = 2682), Nolla (N = 2698) and Moorrees (N = 2674) respectively. A comparison of Kappa values between upper and lower teeth showed marginally higher values for upper incisors and lower molar for all three scoring methods. Small differences in Kappa values were noted between tooth types with the upper first molar having smaller values than other teeth. Percentage agreement ranged from 81 % (Moorrees), 86 % (Nolla) to 87 % (Demirjian). Tooth stage differences between first and second assessments were not more than one stage. Our findings show that Demirjian scoring is marginally more reliable than Nolla or Moorrees. We suggest that (1) data for reliability are tabulated in full to show the quantity and allocation of disagreement between first and second readings, and (2) that the reliability sample is sufficiently large with a wide age range to include multiple different tooth stages.
Cadaver body bags are the conventional method to contain a human body or human remains, which includes the use for storage and transportation of the deceased at any crime scene or disaster scene. During disasters, most often than not, the first responders including the police will be equipped with cadaver body bags to do scene processing of human remains and collection of personal belongings at the disaster site. However, in an unanticipated large scale disasters involving hundreds and thousands of fatalities, cadaver body bags supplies may be scarce. The authors have therefore innovated the cling film plastic wrap as an alternative for the cadaver body bag used at the disaster site. The plastic wrap was tested on six different experimental subjects, i.e. both adult and child mannequins; body parts of the mannequin figure (arm and hand); a human adult subject and an unknown dead body. The strengths of the cling film plastic wrap are discussed in comparison with the cadaver body bag in the aspects of costing, weight, duration of the wrap, water and body fluid resistant properties, visibility and other advantages. An average savings of more than 5000% are noted for both adult body wrap and child body wrap compared to the cadaver body wrap. This simply means that the authors can either wrap 25 adult dead bodies or 80 children dead bodies with the cost of 1 cadaver body bag. The cling film plastic wrap has proven to have significant innovation impact for dead body management particularly by the first responders in large scale disasters. With proper handling of dead bodies, first responders can manage the dead with dignity and respect in an overwhelmed situation to facilitate the humanitarian victim identification process later.