Use In Forensic Science Research Articles

Silver nanoparticles forensic uses and toxicity on vital organs and different body systems

This study aimed to investigate the forensic uses and potential toxicity of silver nanoparticles on vital organs and different body systems. A systematic review methodology was used to identify and critically evaluate the literature on the forensic uses of silver nanoparticles in different fields and to assess their potential toxicity on various vital organs and body systems. The study found that silver nanoparticles have potential forensic uses, particularly in forensic biology and forensic toxicology, but there are concerns about their potential toxicity. The study recommends further research on the mechanisms of toxicity of silver nanoparticles and the development of safe and effective strategies for their use in forensic science. The study’s strengths include its systematic review methodology and use of multiple databases, while limitations include a limited time frame and focus on English language publications. Future research should focus on investigating the potential risks of silver nanoparticle exposure for forensic professionals.

Dye-doped cellulose nanocrystals as novel dusting powders for visualizing latent fingerprints.

Powder-dusting method based on the visual contrast between the background surface and powder-covered ridges of a fingerprint is widely used to develop the invisible latent fingerprints (LFPs) left at crime scenes. Recently, the development of nano-sized powders with excellent optical performances has been extensively explored. In this work, we employed environmentally friendly and low-toxicity cellulose nanocrystals as the novel support. Using dye-doped cellulose nanocrystals as novel dusting powders, two dyes (phenylfluorone and curcumin) were adsorbed on the cellulose nanocrystals by a simple batch adsorption method. The dye-doped cellulose nanocrystals (namely, phenylfluorone-doped cellulose nanocrystals (PDCN) and curcumin-doped cellulose nanocrystals (CDCN)) containing 2% of the loaded mass of both the dyes with bright green fluorescence were developed to visualize LFPs on the surfaces of various substrates (such as glass slide, printing paper, orange plastic card, tile, stainless steel, compact disc, red plastic packing, copper foil and aluminum foil). Images of the LFPs can been obtained by both the dye-doped cellulose nanocrystals with sufficient affinity to the ridges of LFPs. High-quality ridge details with features at the second and third level can be detected by CDCN, whereas PDCN only display the secondary-level features of ridge details. Compared with PDCN, CDCN illustrate higher sensitivity, higher selectivity, and better contrast, especially for detecting fresh and non-fresh LFPs on porous and non-porous substrates, and has the potential for practical use in forensic science.

Problematic issues related to forensic examination of written language and handwriting in pre-trial investigation

The article retrospectively examines the genesis of theoretical and law enforcement issues, legislative and other regulatory frameworks relating to forensic examination of written language and handwriting with a view to improving them and further prospects for their use in forensic science and forensic examination. The genesis of the emergence and introduction of the first state, international, religious, economic and other types of documents, methods and types of their execution and registration, and the improvement of the historical documentary system in our country and the persons who could execute them in various fields of use in the country and in ensuring the vital activity of the population, as well as the mechanism of the first identification actions with this category of writing and handwriting are investigated. The role, essence and significance of written language, handwriting and documentary studies in their historical aspect in terms of formation, improvement and use in establishing and identifying the person who executed a certain document or written text are determined. Separate objectives have been identified to improve knowledge, including subculture and skills, on the detection, establishment and preparation for forensic examination of written language and handwriting by detectives, investigators, forensic specialists, experts, prosecutors, investigating judges and court personnel, taking into account the requirements of the time regarding the use by criminals of documents made both by conventional means and with the help of computer equipment, the Internet, mobile communications, as well as other modern telecommunications achievements and digitalisation of the pre-trial process. The article investigates the peculiarities of forensic methods of examination of written language and handwriting objects to be taken into account by officials who, in particular, conduct pre-trial investigation of criminal offences committed with the use of ordinary or forged written documents, handwriting forgery, and other criminal methods of their use with a view to qualitative preparation and conduct of relevant handwriting and authenticity examinations. Based on the results of the study, the author's scientific positions and ways of solving the existing problematic issues have been developed.

Validation of image stream hashing: A forensic method for content verification.

How do forensic examiners know if they have altered an image stream when converting a digital image from one codec or file container to another for analysis? Forensic standards and best practices recommend avoiding alteration or degradation of multimedia data during transcoding. An image stream hashing method was recently introduced to the forensic science community to answer the question above. This paper offers an initial validation study of image stream hashing method that may answer the question above. The first half of the study's experiments tested the image stream hashing method to measure fitness for use in forensic science while identifying errors and limitations. The study's second phase analyzed the systematic errors detected in initial tests to discover error causation. Causation analysis identified four method limitations subsequently used to develop proposed standard controls of method operations. The final study phase repeated the initial experiments used in the first phase while implementing the proposed standard controls of method operations. Initial test results indicated the method had significant error rates, limiting the effectiveness of the method to only three of the five file types used in the study. The final testing phase revealed that implementing proposed standard controls of method operations reduced the potential systematic errors to a negligible level when using the image stream hashing method for content verification. The validation study concluded that examiners could use the image stream hashing method for forensic science only by implementing error mitigation techniques that utilize the proposed standard controls of method operations.

A plague on both your houses: The debate about how to deal with ‘inconclusive’ conclusions when calculating error rates

To the Editor, There is an ongoing debate about how to deal with ‘inconclusive’ conclusions when calculating error rates. Recent contributions to this debate include, in chronological order, Dror and Scurich (2020), Weller and Morris (2020), Biedermann and Kotsoglou (2021), Arkes and Koehler (2021), Dror (2022) and Arkes and Koehler (2022). All the proposed solutions are inappropriate because they do not address the real problem. The real problem is not what to do with ‘inconclusive’ conclusions but the fact that forensic practitioners report conclusions as ‘identification’, ‘inconclusive’ and ‘exclusion’ at all. The real solution is for practitioners to abandon this practice and, instead, adopt the logically correct framework for interpretation of forensic evidence, the likelihood-ratio framework. Rather than reporting each of their conclusions as one of three categories, practitioners should report them as continuously-valued likelihood-ratio values.1 When conducting tests, if the test pair is a same-source pair, then a good output by the forensic-evaluation system would be a large positive log-likelihood-ratio value, a poorer output would be a small positive log-likelihood-ratio value, a worse output would be a small negative log-likelihood-ratio value, and a much worse output would be a large negative log-likelihood-ratio value. Mutatis mutandis, for a different-source pair, for which a good output would be a large negative log-likelihood-ratio value.2 When calculating error rates in a categorical framework, a penalty value of 1 is assigned to each response that is the incorrect category and a penalty value of 0 is assigned to each response that is the correct category, then the penalty values are averaged. In contrast, an appropriate validation metric for a system that outputs likelihood ratios assigns a small penalty value to each log-likelihood-ratio value that is large in the correct direction, a less small penalty value to each log-likelihood-ratio value that is small in the correct direction, a large penalty value to each log-likelihood-ratio value that is small in the incorrect direction, and an even larger penalty value to each log-likelihood-ratio value that is large in the incorrect direction, then the penalty values are averaged. The penalty values are assigned using a continuously-valued function of the continuously-valued log-likelihood-ratio outputs of the forensic-evaluation system. A well-established validation metric that has these properties is the log-likelihood-ratio cost (Cllr; Brümmer and du Preez, 2006). It has been in use in forensic science since at least 2007 (González-Rodríguez et al., 2007), and its use is recommended in the recently-published Consensus on validation of forensic voice comparison (Morrison et al., 2021).3 An appendix in the latter publication provides an introduction to Cllr and its interpretation.

An Anatomical Study on the Measurement of Stature From Ulnar Length in the Adult Ethnic Khasi Tribal Population of the North Eastern Region of India.

IntroductionThe stature of an individual is an important parameter for establishing identification. The height of an individual can be indirectly estimated from different parts of the skeleton and such measurements are of great use in forensic science, anatomy, and anthropometry. This study was an attempt to formulate a linear regression equation for estimation of stature by measuring the ulnar length in the living adult Khasi population.MethodsThe study population consists of 164 subjects (Male: 118; Female: 46) between 25 and 45 years of age. The left and right ulnar lengths were measured from the tip of the olecranon process to the tip of the styloid process with the elbow flexed and palm spread over the opposite shoulder by a spreading caliper. The measurements of the stature of the volunteers were done in the standard anatomical standing position with a bared foot with the head in the Frankfort plane. The documented data were calculated by the standard statistical software.ResultsThe height and ulnar length in males (160.85 ± 6.34 cm and 24.41 ± 1.10 cm, respectively) were found to be significantly (p < 0.001) higher than females (149.56 ± 2.95 cm and 22.58 ± 0.47 cm, respectively). Significant positive correlation coefficient (r) between height (cm) and ulnar length (cm) were observed in both males (r = 0.955, P < 0.001) and females (r = 0.915, P < 0.001), respectively.ConclusionThe length of the ulna provides an accurate and reliable means in estimating the height of an individual; being almost a percutaneous bone, its length can be measured easily. The regression formulae that were derived in this study will be useful for clinicians, human anatomists, archeologists, anthropologists, and forensic experts.

The need for research-based tools for personnel selection and assessment in the forensic sciences

The popularity of forensic science television programs has created a hiring challenge for forensic science laboratories. Laboratories receive unprecedented numbers of applicants, yet struggle to identify highly-qualified candidates. Forensic examiners must possess a unique set of knowledge, skills, and abilities (KSAs) plus other characteristics. They must be critical thinkers, detail-oriented, decisive, and self-regulated; be able to communicate clearly and effectively within the laboratory, with customers (typically investigators or attorneys), and in the courtroom; and demonstrate the required core competencies. Currently, no validated instruments, standardized job descriptions, or lists of KSAs exist to aid in forensic science personnel recruitment and assessment, often resulting in high turnover leading to costly new recruitment and training cycles. This article describes how industrial/organizational psychology develops methods and tools to improve workforce selection; describes some tools currently in use in forensic science; and advocates for research and development of better tools for use in forensic science.

Age-Related Trends in the Trabecular Micro-Architecture of the Medial Clavicle: Is It of Use in Forensic Science?

The mechanical and structural properties of bone are known to change significantly with age. Within forensic and archaeological investigations, the medial end of the clavicle is typically used for estimating the age-at-death of an unknown individual. Although, this region of the skeleton is of interest to forensic and clinical domains, alterations beyond the macro-scale have not been fully explored. For this study, non-destructive micro-computed tomography (μ-CT) was employed to characterize structural alterations to the cancellous bone of the medial clavicle. Fresh human cadaveric specimens (12-59 years) obtained at autopsy were utilized for this study, and were scanned with a voxel size of ~83 μm. Morphometric properties were quantified and indicated that the bone volume, connectivity density, mineral density, and number of trabeculae decreased with age, while the spacing between the trabeculae increased with age. In contrast to other sub-regions of the skeleton, trabecular thickness, and degree of anisotropy did not correlate with age. Collectively, this could suggest that the network is becoming increasingly perforated with age rather than exhibiting trabecular thinning. These results are used in the context of deriving a potential protocol for forensic investigations by using this particular and largely unexplored region of the skeleton, and provide inspiration for future experiments concerning micro-architectural and small scale changes in other regions of the human skeleton.

Classification of condom lubricants in cyanoacrylate treated fingerprints by desorption electrospray ionization mass spectrometry

Traces of condom lubricants in fingerprints can be valuable information in cases of sexual assault. Ideally, not only confirmation of the presence of the condom but also determination of the type of condom brand used can be retrieved. Previous studies have shown to be able to retrieve information about the condom brand and type from fingerprints containing lubricants using various analytical techniques. However, in practice fingerprints often appear latent and need to be detected first, which is often achieved by cyanoacrylate fuming. In this study, we developed a desorption electrospray ionization mass spectrometry (DESI-MS) method which, combined with principal component analysis and linear discriminant analysis (PCA-LDA), allows for high accuracy classification of condom brands and types from fingerprints containing condom lubricant traces. The developed method is compatible with cyanoacrylate (CA) fuming. We collected and analyzed a representative dataset for the Netherlands comprising 32 different condoms. Distinctive lubricant components such as polyethylene glycol (PEG), polydimethylsiloxane (PDMS), octoxynol-9 and nonoxynol-9 were readily detected using the DESI-MS method. Based on the analysis of lubricant spots, a 99.0% classification accuracy was achieved. When analyzing lubricant containing fingerprints, an overall accuracy of 90.9% was obtained. Full chemical images could be generated from fingerprints, showing the distribution of lubricant components such as PEG and PDMS throughout the fingerprint, while still allowing for classification. The developed method shows potential for the development of DESI-MS based analyses of CA treated exogenous compounds from fingerprints for use in forensic science.

Fungal succession during mammalian cadaver decomposition and potential forensic implications

The necrobiome is the postmortem community that includes bacteria, fungi, arthropods, and other cadaver-associated organisms. It has been suggested as biological evidence for forensic investigation. Fungi form distinctive mildew spots in colonizing decomposing bodies, converting them into moldy cadavers. However, the postmortem fungal community consists of more than these visible species. Characterizing the succession pattern of the fungal community during decomposition is valuable not only for understanding the ecosystem composition of the cadaver decomposition islands but also for contributing to forensic investigations. In the present study, the fungal composition of pig cadavers and succession patterns during decomposition were investigated with high-throughput sequencing. The succession patterns were easier to discern in outdoor cadavers, compared with those that were placed indoors. The metabarcoding approach revealed trends linking particular fungal taxa with specific postmortem intervals (PMIs). Dominant species increased notably in cadavers and soil. Furthermore, the succession of the soil community was driven by the cadaver decomposition. Significant mycoflora differences were observed between environmental and cadaveric soil. The results obtained suggested that postputrefaction mycoflora have considerable potential for PMI estimation, particularly in cases that involve heavily decomposed bodies. In addition, the diversity of fungal communities revealed by the metabarcoding approach allowed us to discriminate the sites of cadaver decomposition, implying that postputrefaction mycoflora may be helpful in identifying the environment in which a cadaver has been placed, or the original location from which a cadaver has been moved. Our results provide an important step towards developing fungal evidence for use in forensic science and add to the growing body of work on postmortem microbial communities.

Tiny, shiny, and colorful microplastics: Are regular glitters a significant source of microplastics?

Used in significant volumes in make-up, craft activities, and –more recently– in textile products, glitters are among single-use plastics, and are often made of polyethylene terephthalate. Even though a wealth of studies focus on the sources of microplastics in the environment and biota, glitters produced in various countries, and used extensively in entertainment events, shows and carnivals around the globe, not to mention by virtually anyone in daily life settings, have been relatively ignored as a major source of microplastics. That is why the present study focuses specifically on plastic glitters, and attempts to track them in the environment, in a manner comparable to their use in forensic science where glitters are often used as trace evidence associating a suspect with a specific murder case. Doing so led to various pieces of evidence of the presence of glitters –arguably a stealthy source of microplastics – in samples taken from the environment at a wide range of locations around the world.

Molecular Basis of the Chemiluminescence Mechanism of Luminol.

Light emission from luminol is probably one of the most popular chemiluminescence reactions due to its use in forensic science, and has recently displayed promising applications for the treatment of cancer in deep tissues. The mechanism is, however, very complex and distinct possibilities have been proposed. By efficiently combining DFT and CASPT2 methodologies, the chemiluminescence mechanism has been studied in three steps: 1) luminol oxygenation to generate the chemiluminophore, 2) a chemiexcitation step, and 3) generation of the light emitter. The findings demonstrate that the luminol double-deprotonated dianion activates molecular oxygen, diazaquinone is not formed, and the chemiluminophore is formed through the concerted addition of oxygen and concerted elimination of nitrogen. The peroxide bond, in comparison to other isoelectronic chemical functionalities (-NH-NH-, -N- -N- -, and -S-S-), is found to have the best chemiexcitation efficiency, which allows the oxygenation requirement to be rationalized and establishes general design principles for the chemiluminescence efficiency. Electron transfer from the aniline ring to the OO bond promotes the excitation process to create an excited state that is not the chemiluminescent species. To produce the light emitter, proton transfer between the amino and carbonyl groups must occur; this requires highly localized vibrational energy during chemiexcitation.

Forensic Accounting &amp;amp; Financial Investigation

Forensic Accounting &amp;amp; Financial Investigation

Toxicological analyzes and its use in forensic science

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Normative decision analysis in forensic science

This paper focuses on the normative analysis—in the sense of the classic decision-theoretic formulation—of decision problems that arise in connection with forensic expert reporting. We distinguish this analytical account from other common types of decision analyses, such as descriptive approaches. While decision theory is, since several decades, an extensively discussed topic in legal literature, its use in forensic science is more recent, and with an emphasis on goals such as the analysis of the logical structure of forensic expert conclusions regarding, for example, propositions of common source of evidential and known materials. Typical examples are so-called identification (or, individualization) decisions, especially categorical conclusions according to which fingermarks (or stains of biological nature, handwriting, etc.) come from a particular a person of interest. We will present and compare ways of stating forensic identification decisions in decision-theoretic terms and explain their underlying rationale. In particular, we will emphasize the importance of viewing this analysis as normative in the sense of providing a reflective rather than a prescriptive reference point against which people in charge of forensic identification decisions may compare their otherwise (possibly) intuitive and informal reasoning, before acting. Normative decision analysis in forensic science thus provides a vector through which current practice can be articulated, scrutinized and rethought.

Cationic dye-diatomite composites: Novel dusting powders for developing latent fingerprints

Most fingerprints left at crime scenes are latent and require treatment to render them visible. Powder method, the most widely used procedure for developing latent fingerprints, is based on the visual contrast between background surface and powder-covered fingerprint region, thus dusting powders with excellent performance are urgently needed. Four cationic dye-diatomite composite powders with different colors have been prepared relying on the adsorption between cationic dye molecule and diatomite. Compared with synthetic silica matrix, the employment of natural diatomite greatly reduces the amount of dye usage, which is simple, green and low-cost. The cationic dye-diatomite composite powders are successfully used as novel dusting powders for developing latent fingerprints on various substrates including glass slides, notebook paper, PVC sheets, ceramic tile, water bottle label, stainless steel coin, tea caddy, compact disc and packing box. High-quality patterns of fingerprints with second level features can be obtained within a short period of time. This work shows that the cationic dye-diatomite composite powders have high sensitivity, high selectivity and good contrast and are promising for practical use in forensic science.

A user-friendly technical set-up for infrared photography of forensic findings

Infrared photography is interesting for a use in forensic science and forensic medicine since it reveals findings that normally are almost invisible to the human eye. Originally, infrared photography has been made possible by the placement of an infrared light transmission filter screwed in front of the camera objective lens. However, this set-up is associated with many drawbacks such as the loss of the autofocus function, the need of an external infrared source, and long exposure times which make the use of a tripod necessary. These limitations prevented up to now the routine application of infrared photography in forensics.In this study the use of a professional modification inside the digital camera body was evaluated regarding camera handling and image quality. This permanent modification consisted of the replacement of the in-built infrared blocking filter by an infrared transmission filter of 700nm and 830nm, respectively. The application of this camera set-up for the photo-documentation of forensically relevant post-mortem findings was investigated in examples of trace evidence such as gunshot residues on the skin, in external findings, e.g. hematomas, as well as in an exemplary internal finding, i.e., Wischnewski spots in a putrefied stomach.The application of scattered light created by indirect flashlight yielded a more uniform illumination of the object, and the use of the 700nm filter resulted in better pictures than the 830nm filter. Compared to pictures taken under visible light, infrared photographs generally yielded better contrast. This allowed for discerning more details and revealed findings which were not visible otherwise, such as imprints on a fabric and tattoos in mummified skin.The permanent modification of a digital camera by building in a 700nm infrared transmission filter resulted in a user-friendly and efficient set-up which qualified for the use in daily forensic routine. Main advantages were a clear picture in the viewfinder, an auto-focus usable over the whole range of infrared light, and the possibility of using short shutter speeds which allows taking infrared pictures free-hand. The proposed set-up with a modification of the camera allows a user-friendly application of infrared photography in post-mortem settings.

Integrating the microbiome as a resource in the forensics toolkit

The introduction of DNA fingerprinting to forensic science rapidly expanded the available evidence that could be garnered from a crime scene and used in court cases. Next generation sequencing technologies increased available genetic data that could be used as evidence by orders of magnitude, and as such, significant additional genetic information is now available for use in forensic science. This includes DNA from the bacteria that live in and on humans, known as the human microbiome. Next generation sequencing of the human microbiome demonstrates that its bacterial DNA can be used to uniquely identify an individual, provide information about their life and behavioral patterns, determine the body site where a sample came from, and estimate postmortem intervals. Bacterial samples from the environment and objects can also be leveraged to address similar questions about the individual(s) who interacted with them. However, the applications of this new field in forensic sciences raises concerns on current methods used in sample processing, including sample collection, storage, and the statistical power of published studies. These areas of human microbiome research need to be fully addressed before microbiome data can become a regularly incorporated evidence type and routine procedure of the forensic toolkit. Here, we summarize information on the current status of microbiome research as applies to the forensic field, the mathematical models used to make predictions, and the possible legal and practical difficulties that can limit the application of microbiomes in forensic science.

The evaluation of cases using synthetic cannabinoid in Trabzon and the surrounding provinces

Although popularly considered as a modern utility, the study of fingerprints and skin ridge patterns is probably the oldest of all sciences. Fingerprints once formed remain permanent and never change throughout the life. The present study includes 150 cases of angiographically proven myocardial infarction patients and 150 cases of healthy normal individuals. The fingerprints of both hands were taken by plain and rolled method on white paper to determine the correlation between fingertip patterns and myocardial infarction. It is noted that there is significant decrease in loops in thumb in males with significant increase in whorls in little finger in males, and thumb and little finger in left hand in myocardial infarction patients. Also there is significant decrease in arches in little finger in males and thumb in females with significant increase in arches in little finger in females in myocardial infarction patients. Moreover, there is significant decrease in loops with corresponding increase in whorls in males, (M+F) combined series and left hand of myocardial infarction patients as compared to the controls. The mean value of finger ridge count in myocardial infarction patients is increased in both sexes but not significant. Thus, apart from its use in forensic science for identification and disputed paternity, fingerprint can also be use in predicting the myocardial infarction in healthy individual at an earlier age.

Towards a validation of surface-enhanced Raman scattering (SERS) for use in forensic science: repeatability and reproducibility experiments

In order for a new analytical technique such as surface-enhanced Raman scattering (SERS) to be used in a routine manner, data and studies on the validation of the method are required. In that context, we performed a systematic study of the variability observed at different levels of the analytical procedure (i.e. respectively measurement, sampling, colloids aliquots, colloids batches, laboratories). Our goal is to provide data towards a qualitative validation of the technique for identification purposes. Three molecules of forensic interest were used as probes, respectively crystal violet, methamphetamine and 2,4,6-trinitrotoluene (TNT).We demonstrate that the method is repeatable with RSD and multivariate techniques (PCA). The % RSD at the different analytical stages vary between the molecules and the peaks considered. The repeatability is on the order of 2-6% for crystal violet, and 5-16% for TNT. Methamphetamine binds very weakly to the silver colloids giving much greater variability in the measurements (5-29%). We show that spectra measured in the same conditions (e.g. same laboratory and instrument), even a few days apart, are comparable and stable. The largest source of variation has been identified to be the measurement conditions and the associated random fluctuations in intensity (i.e. Brownian motion of the particles, solvent evaporation and concentration). The influence of the substrate is confirmed to be negligible. However, the reproducibility between different laboratories and different instruments introduced the largest source of variability (∼ 10-70%). Despite these factors, we demonstrate that qualitative identification of the species under analysis by measurement and comparison of peaks position is always successful even though quantitative analysis is, at present, difficult. Regardless of the amount of variability determined, the molecules could always be successfully identified, even on different instruments from different laboratories by utilizing the criterion proposed in the literature (i.e. 3:1 signal-to-noise ratio).