Forensic Purposes Research Articles

A survey of soil elemental variability in Singapore parks for forensic purposes

Soil, as a surviving trace after contact and transfer between contacting surfaces at a crime scene, can be recovered and analyzed to infer the presence of persons or tools at the scene and prior activity leading to its deposition. With its vast diversity and heterogeneity, it varies in composition from place to place, providing a basis for trace examiners to distinguish visually similar-colored soils. Unlike countries with native topsoil, Singapore’s urban lands are commonly filled with man-altered and man-transported soil, with relatively little known about the variations of soil’s characteristics within a small, localized area. The current study surveyed the soil’s elemental variability in Singapore parks, which are green spaces for public leisure use. Past installations of recreational facilities and landscaping with fast-growing vegetation in parks inevitably cause disturbance to the original natural soil and mixing with extraneous soil, further contributing to the heterogeneity of the park’s topsoil composition. In our sampling approach, visually similar-colored surface soils were collected from within a 1-m2 site, sites in proximity within a park, and parks across Singapore. The collected soils were dried and sieved into clay- and silt-size fractions for elemental analysis using WDXRF and SEM/EDS. To examine the extent of the spatial elemental variability, we adopted three-sigma interval match criteria and a discriminative model incorporating relative data, square root values and the Canberra distance measure for data processing and pairwise comparison of soil samples. The study also aimed to develop soil databases encompassing soils across Singapore with the intent of understanding the value of soil evidence within a local context.

Application of entire dental panorama image data in artificial intelligence model for age estimation

BackgroundAccurate age estimation is vital for clinical and forensic purposes. With the rapid advancement of artificial intelligence(AI) technologies, traditional methods relying on tooth development, while reliable, can be enhanced by leveraging deep learning, particularly neural networks. This study evaluated the efficiency of an AI model by applying the entire panoramic image for age estimation. The outcome performances were analyzed through supervised learning (SL) models.MethodsTotal of 27,877 dental panorama images from 5 to 90 years of age were classified by 2 types of grouping. In type 1 they were classified by each age and in type 2, applying heuristic grouping, the age over 20 years were classified by every 5 years. Wide ResNet (WRN) and DenseNet (DN) were used for supervised learning. In addition, the analysis with ± 3 years of deviation in both types were performed.ResultsFor the DN model, while the type 1 grouping achieved an accuracy of 0.1016 and F1 score of 0.058, the type 2 achieved an accuracy of 0.3146 and F1 score of 0.2027. Incorporating ± 3years of deviation, the accuracy of type 1 and 2 were 0.281, 0.7323 respectively; and the F1 score were 0.1768, 0.6583 respectively. For the WRN model, while the type 1 grouping achieved an accuracy of 0.1041 and F1 score of 0.0599, the type 2 achieved an accuracy of 0.3182 and F1 score of 0.2071. Incorporating ± 3years of deviation, the accuracy of type 1 and 2 were 0.2716, 0.7323 respectively; and the F1 score were 0.1709, 0.6437 respectively.ConclusionsThe application of entire panorama image data for supervised with classification by heuristics grouping with ± 3years of deviation for supervised learning models and demonstrated satisfactory outcome for the age estimation.

Low-level point heteroplasmy detection in human mitogenomes amplified with different polymerases and sequenced on MiSeq FGx platform.

Massively parallel sequencing of mitogenomes usually requires prior amplification. The PCR step may influence the quality of the data obtained, especially when low-level heteroplasmy detection is applied. The aim of this study was to compare the reliability of two different DNA polymerases in detecting homoplasmic and heteroplasmic substitutions in human mitogenomes. Mitogenomes of five samples were amplified with Long PCR Enzyme Mix from Fermentas or TaKaRa LA Taq DNA Polymerase from TaKaRa. Then, NexteraTM XT DNA libraries were sequenced on MiSeq FGx platform (Illumina). mtDNA substitutions were called for alternative variants above the 1% level. All homoplasmic substitutions detected in amplicons generated with polymerases studied here and sequenced on MiSeq FGx system were consistently identified as homoplasmies with alternative sequencing methods. TaKaRa LA Taq DNA Polymerase was found to be less accurate in low-level heteroplasmy detection than Long PCR Enzyme Mix enzyme as more false negative and false positive results were observed for minority variants called above the 1% level. Nevertheless, both PCR systems studied can be successfully used to detect authentic mtDNA substitutions, for which minority variants exceed the 3.61% level assuming at least 10,000x coverage and sequencing Nextera XT DNA libraries on MiSeq FGx machine. The accuracy and sensitivity of point heteroplasmy detection with the MiSeq FGx instrument varies on polymerase used for mtDNA amplification. Therefore, it is recommended to validate the laboratory protocols used for mtDNA substitution detection prior to their implementation for the forensic or medical genetics purposes.

Dna forensic data bank, facts and perception: The Italian experience

In 2016 the Italian National Dna database for forensic purposes finally went live. After seven years of “operational life”, numbers and results are still scarce. The aim of the study is to evaluate the actual knowledge and perceived usefulness of this investigative tool among a significant sample of Italian magistrates. The research was conducted through the administration of an anonymous structured questionnaire to magistrates belonging to the Court of Milano. The overall picture emerging from the questionnaire is a worrying lack of preparation regarding the functioning of the Dna database among judges and public prosecutors. This situation affects the performance of the instrument. The authors believe that a specific and compulsory training for magistrates should be introduced.

Sexual Dimorphism of Hand Length Ratios among Igede Ethnic Group in Nigeria

Nowadays sex-age gap, stature, and ancestral ties are used as biological markers to identify people for forensic purposes. This study was carried out to investigate sexual dimorphic characterization in a small ethnic group in northern Nigeria as seen in hand lengths and ratios. The present study was conducted on 862 subjects (308 males and 554 females) aged 11 to 19. Hand length measurements were taken from the ventral crease to the tip of the finger as r2d, l2d, l2d, l4d, and 2d:4d respectively. Student’s t-test was used to describe data and sex differentiation. Pearson’s correlation analysis was applied to establish relationship between stature and age with hand length ratios. Multiple regression models were generated to back up the strength of relationship by prediction from digit lengths for stature. P<0.05 was considered statistically significant.

Hexahydrocannabinol Pharmacology, Toxicology, and Analysis: The First Evidence for a Recent New Psychoactive Substance.

During the last two years, hexahydrocannabinol (HHC), the hydrogenated derivative of tetrahydrocannabinol has been freely sold by internet websites as a "legal" replacement to THC and cannabis in a range of highly attractive branded and unbranded products, some of which are sold as "legal highs". Potentially, there could be a large demand for HHC products by individuals in Europe and internationally. Studies reporting HHC pharmacology, toxicology and analysis were identified from Pubmed and Scopus databases, and official international organizations' websites were considered. HHC showed the effects of the typical cannabinoid on the central nervous system, with lower potency than Δ9-THC. A few studies highlighted that 9(R)-HHC is more potent than 9(S)-HHC. This molecule showed an affinity for cannabinoid receptor CB1 both in vitro and in vivo, suggesting a possible therapeutic effect in several pathologies. However, the affinity for the CB1 receptor suggests a possible addiction potential, inducing the users to misuse it. Since actual intoxication cases have not yet been reported, the HHC harmful potential was not described, probably due to the lack of effective analytical methods to detect HHC in biological matrices. Conversely, different analytical assays were developed and validated to separate HHC epimers in natural and non-natural sources. Similarly to other NPS, the HHC represents a cheaper alternative to the controlled Δ9-THC. Its monitoring is a crucial challenge for toxicological and forensic purposes. To this concern, it is essential to further investigate HHC to support health providers in the identification of related intoxications.

Effect of Format Conversion on Source Identification from Audio Recordings: A Study for Forensic Purposes

Effect of Format Conversion on Source Identification from Audio Recordings: A Study for Forensic Purposes

Assessment of gunshot residue detection on a large variety of surfaces by portable LIBS system for crime scene application

The application of Laser-Induced Breakdown Spectroscopy (LIBS) in forensic science has garnered increasing attention. The ability to perform real-time, on-site analysis of Gunshot Residue (GSR) particles and potential elements originating from bullets or projectile cores on various surfaces holds the potential to assist in resolving firearms-related cases. This includes facilitating trajectory determination by locating distinct impact points and identifying the types of ammunition used. This study evaluates the utilization of a portable LIBS device for ballistic forensic purposes. Additionally, it focuses on the assessment of potential false positives and false negatives arising from the different materials where the shots have been fired. Since the system performs laser ablation of both surface particles and the substrate, it emphasizes the importance of conducting preliminary screening in an area with the same composition as the impact zone to minimize potential false positives during direct surface analysis. Furthermore, the results demonstrate the capability to detect the constituent elements of characteristic gunshot residue particles (GSR particles): lead (Pb), antimony (Sb), and barium (Ba) adhering to bullets, as well as the principal elements composing the jacket or core of the projectile: lead (Pb), copper (Cu), and zinc (Zn) through direct analysis, without the need for a sampling kit, on different surfaces such as walls, furniture, or fabrics. Analyses conducted a month after the shots were fired indicate the potential for finding residues in the vicinity of the bullet hole. Analyses conducted a month after the shots were fired indicate the possibility of finding residues in the area around the bullet hole.

Cardiovascular drugs and suicide death: Determination of carvedilol, amlodipine, doxazosin and diltiazem in two fatal cases

A number of medical conditions are identified as risk factors for suicide death; in particular, cardiovascular illnesses are recognized as a major suicide risk factor. In this case, self-poisoning is the common method of suicide and cardiovascular drugs are among the major medications associated with fatal overdose, with calcium channel blockers being one of the most common agents. The present study describes two different fatal suicide cases involving four cardiovascular drugs: carvedilol, doxazosin and amlodipine (case 1) and diltiazem (case 2). The concentrations of the target cardiovascular drugs in the different biological specimens (central and femoral blood, urine, liver, brain) are presented, giving information about the potentially fatal data and the distribution of the drugs in the body. The study led to the implementation of a fast, sensitive and simple method for the detection and quantification of the four commonly prescribed cardiovascular drugs in post-mortem specimens including fluids and tissues for forensic purposes. The method was fully validated. The toxicological results of the studied cases are discussed, along with the autopsy results, histopathological evidence, and circumstances of death. The toxicological findings presented in the study provide new data regarding cardiovascular drugs in different post-mortem specimens, which will contribute to the currently limited knowledge about the toxicological profile of cardiovascular drugs and their distribution.

Intra- and inter-rater reliability of a manual codification system for footwear impressions: first lessons learned from the development of a footwear database for forensic intelligence purposes

To generate forensic intelligence from footwear impressions and link crime scenes, most law enforcement agencies and forensic laboratories rely on a manual codification system based on pattern recognition and classification by human analysts. However, although they are commonly used in practice, to date we still know little about the reliability of such systems. Taking advantage of the development of a footwear database for forensic intelligence purposes at the Laboratoire de sciences judiciaires et de médecine légale in Quebec (Canada), this study aims to make a preliminary assessment of the intra- and inter-rater reliability (i.e., the level of repeatability over time and the level of consensus between analysts) of the proposed codification system. To do so, three forensic intelligence analysts classified a set of 27 crime scene impressions and test impressions at two different times (two weeks apart). Percent agreement, Cohen’s Kappa, and Light’s Kappa were then calculated. Results show that two out of three analysts have reached an almost perfect level of intra-rater agreement, while the other have achieved a substantial level of intra-agreement, and that all analysts have reached a substantial level of inter-rater agreement. Findings suggest that, although a few patterns may have lower levels of agreement, overall, the developed codification system presents a satisfactory level of reliability. This preliminary study thus suggests that contrary to what advocates of fully automated systems may sometimes imply, manual codification of footwear impressions may be fairly appropriate for intelligence purposes. It calls for further evaluative research in the field.

Electron activated dissociation - a complementary fragmentation technique to collision-induced dissociation for metabolite identification of synthetic cathinone positional isomers

Over the last decade, a remarkable number of new psychoactive substances (NPS) have emerged onto the drug market, resulting in serious threats to both public health and society. Despite their abundance and potential toxicity, there is little information available on their metabolism, a crucial piece of information for clinical and forensic purposes. NPS metabolism can be studied using in vitro models, such as liver microsomes, cytosol, hepatocytes, etc. The tentative structural elucidation of metabolites of NPS formed using in vitro models is typically carried out using liquid chromatography combined with high-resolution tandem mass spectrometry (LC-HRMS2) with collision-induced dissociation (CID) as a fragmentation method. However, the thermally-excited ions produced with CID may not be sufficient for unambiguous identification of metabolites or their complete characterization. Electron-activated dissociation (EAD), a relatively new fragmentation approach that can be used to fragment singly-charged ions, may provide complementary structural information that can be used to further improve the confidence in metabolite identification. The aim of this study was to compare CID and EAD as fragmentation methods for the characterization and identification of synthetic cathinone positional isomers and their metabolites. The in vitro metabolism of 2-methylethcathinone (2-MEC), 3-methylethcathinone (3-MEC) and 4-methylethcathinone (4-MEC) was investigated with both CID and EAD methods using LC-HRMS2. Four, seven and six metabolites were tentatively identified for the metabolism of 2-MEC, 3-MEC and 4-MEC, respectively. Here, the metabolism of 3-MEC and 2-MEC is reported for the first time. The EAD product ion mass spectra showed different fragmentation patterns compared to CID, where unique and abundant product ions were observed in EAD but not in CID. More importantly, certain EAD exclusive product ions play a significant role in structural elucidation of some metabolites. These results highlight the important role that EAD fragmentation can play in metabolite identification workflows, by providing additional fragmentation data compared with CID and, thus, enhancing the confidence in structural elucidation of drug metabolites.

The uselessness of using salivary microbiota in forensic identification purposes of a person with recent antibiotic use

The detection of microbial flora changes in saliva samples because of antibiotic use through advanced molecular genetic analysis is important for forensic and clinical applications. This study aims to reveal the variability in the microbial structure of human saliva after antibiotic use with metagenomic analysis techniques from a forensic point of view. Within the scope of the study, saliva samples were collected from patients who were under the effect of regional anesthesia to be administered a standardized course of antibiotic therapy that lasted for a week. The analysis was conducted on 56 saliva samples from 14 individuals over four different time intervals. Isolation of the 16S rRNA region and PCR analysis were performed prior to sequence analysis to determine the microbiome structure of the samples at phylum, genus, and species levels. As expected, changes were observed in bacterial species found in saliva samples after administration of antibiotics and this was linked to the specific type of antibiotics that were administered. This change was statistically significant for Firmicutes, Spirochetes, and Verrucomicrobiota. Furthermore, although the oral microbiome tends to return to its former state at the phylum and genus level within a 4-week period after the start of antibiotic use, it is observed that the change, especially in some bacterial species, still continues. The findings of this study show that because of the inability of stabilization at species-level in a period of 4 weeks from the start of antibiotic use, it is not suitable to assess saliva samples at species-level for forensic identification.

Stand‐off Raman spectroscopy is a promising approach for the detection and identification of bloodstains for forensic purposes

AbstractStand‐off Raman spectroscopy combined with chemometrics was demonstrated to have great potential for detecting and identifying biological stains from a distance for forensic purposes. Bloodstain spectra were collected using a handheld Raman spectrometer equipped with a stand‐off attachment and compared with spectra acquired with a benchtop Raman microscope. The two sets of spectra were visually similar, supporting the potential use of a handheld Raman spectrometer with stand‐off attachment for blood detection at the scene of crime. In addition, the stand‐off Raman spectra of bloodstains were correctly identified using a previously built SVM‐DA model for the identification of all main body fluids (Muro et al., Forensic Chemistry, 2016). Stand‐off Raman spectroscopy opens a new potential opportunity for further development of Raman spectroscopy as a universal tool for detecting and identifying body fluid traces for forensic purposes.

Comparative upconversion emission studies in AF3: Tm3+/Yb3+ (A=La, Y and Gd) phosphor for latent fingermarks detection

In this work the effect of change of host lattice on upconversion emission properties of Tm3+/Yb3+ doped/codoped fluoride upconversion phosphor particle with host variations is discussed. Lanthanum (La), yttrium (Y) and gadolinium (Gd) based fluoride hosts are selected and Tm3+/Yb3+ ions combination is incorporated via chemical co-precipitation method. The structural and optical properties of developed systems is studied through FE-SEM, XRD, FTIR, Thermogravimetric analysis and visible upconversion emission. Further, these samples were utilised for latent fingermarks detection on different difficult surfaces. Results obtained are appreciable for security and forensic detection purposes.

Success rate of rapid DNA technology in kinship analysis for forensic purpose.

Reducing the time required for DNA analysis in forensic genetics can yield significant benefits, both in determining genealogical relationships for legal proceedings and in criminal cases. Swift identification of individuals plays a pivotal role in solving crimes and apprehending perpetrators. Additionally, in situations like mass disasters, prompt victim identification holds utmost importance. The Rapid DNA technology, introduced in 2012 to expedite DNA analysis, has evolved to streamline the process into a single step. This advancement not only minimizes the risk of human error and contamination, but also boasts a remarkable time advantage, delivering results in as little as 90min. In this study, DNA profiles of 30 families (consisting of mothers, fathers, and children) were analyzed using the RapidHITTM ID System. The system automatically calculated maternity-paternity probabilities to assess the suitability of Rapid DNA technology for kinship analysis. For validation, DNA profiles were also generated using the 3500 GA method. The study revealed that 9 out of 30 families exhibited discrepancies in DNA profiling, leading to inaccuracies in automatic kinship analysis. Consequently, while the method offers rapid and user-friendly advantages for forensic sciences, the software underlying the system requires re-evaluation. Issues such as maternal-paternal exclusion in kinship analyses, arising from challenges like un-called alleles, warrant further attention.

Pilot study on FT-IR and GC analysis of inhalant substances (thinners and glues) for forensic purpose

Abuse of chemicals classified as inhalants, particularly volatile, for producing effects resembling those of sedatives and other CNS depressants has repeatedly been recorded from numerous locations across the world. This problem is gaining increased attention every day, just like the abuse of other potent drugs. In general, these substances, including paint thinner, glues, etc., do not carry any legal restrictions; therefore, they pose a noxious attraction for teenagers. Keeping in view the danger of such substances, the present research work was initiated in order to generate a Fourier transform infra-red spectroscopy (FT-IR) and gas chromatography (GC) database of a few frequently available inhalant type substances. Instrumental methods used in this study are common and versatile from a forensic analysis point of view. The use of FT-IR and GC has also clarified the comparative application obligation when samples are pure. The results of this study are novel and futuristically useful in forensic scientific investigation.

A forensic application of genetic markers for distinction between drug-type and fiber-type Cannabis sativa L.

Genetic markers can represent a valuable tool for forensic purposes in discriminating between fiber-type and drug-type cannabis. The aim of this research was to evaluate developed genetic markers for tetrahydrocannabinolic acid synthase (THCAS) when applied on certified hemp (14 varieties) and forensic casework samples of four chemotypes (40 seizures). Chemotype-associated PCR-based markers did not enable reliable selective amplification despite the difference in cannabinoid composition. In order to characterize forensic samples of unknown origin, THCAS sequencing was performed. The comparison of THCAS sequences, including additional accessions, indicated high genetic similarity of hemp varieties. Confiscated samples of intermediate, THC, CBD and CBG type were clearly separated from fiber-type accessions and assigned to drug-type cluster. Despite the unknown origin, their position on the tree support the notion that they are more related to drug-type accessions than to the fiber-type. However, no clear distinction between chemotypes was found. Furthermore, 26 amino acid substitutions were revealed in THCAS that clearly separate hemp varieties and neither of them cluster with any other tested sample.

Study on Script Independent Handwritten Document Analysis for Forensics

Abstract: Forensic investigations including document authenticity, forgery detection, and signature verification all heavily rely on handwritten papers. These papers are typically subject to subjective and time-consuming manual assessment by forensic experts as part of the analysis and examination process. The development of automated methods for script-independent handwritten document analysis has completely changed the area and made objective analysis possible. The development of script-independent handwritten document analysis for forensic purposes is explored in this research article. We go over the difficulties encountered in this field and provide several methods and approaches used to solve them. We also look at the advantages, drawbacks, and potential applications of script independent handwritten document analysis in forensic investigations

Construction and evaluation of a novel set of 90 microhaplotypes for forensic applications using NGS technology

Microhaplotypes (MHs), small sets of linked single nucleotide polymorphisms (SNPs), are becoming a valuable tool for paternity testing, personal identification and other different forensic purposes due to their advantages of both short tandem repeats (STRs) and SNPs. However, only a small part of MHs with small segments have been developed and reported so far. And the current population genetic data of MHs are still insufficient. MHs with small segments possess unique advantages in mixture deconvolution, degradation material identification, noninvasive prenatal paternity testing and even medical tumor diagnostic applications. In the present study, a set of 90 autosomal MHs whose PCR amplicon lengths are from 90–150 bp, of which 58 MHs are less than or equal to 100 bp are selected, and assembled into an amplification multiplex system optimized for Ion S5™ System for forensic application. Genetic diversity study of 90 MHs in the populations from different intercontinental regions shows that the polymorphism information content (PIC) values of 83 MHs are greater than 0.4 in populations from East Asia (EAS), and the average PIC value of 90 MHs is greater than 0.5. A total of EAS populations shows the highest cumulative match probability (CMP) and cumulative probability of exclusion (CPE) values in five intercontinental populations. The CMP and CPE values of 90 MHs in EAS are 1.1688 × 10−54 and 0.999999999998954. The informativeness for assignment (In) values of the 90 MHs are calculated based on data from five intercontinental populations, and the In values of 20 MHs have greater than 0.1, indicating that the 20 MHs are high effectiveness in distinguishing different intercontinental populations, which can be used as candidate ancestry informative markers. Further, we have studied the polymorphisms of the 90 MHs based on 224 unrelated individuals of Henan Han population, China, and obtained the frequency data of the 90 MHs. In the Henan Han population, the effective number of alleles (Ae) of the 90 MHs ranges from 1.7649 (MH45) to 3.9792 (MH50), and the Ae values of 10 MHs reach to 3.0; the Ae values of 80 MHs are greater than 2, and the average Ae value for these MHs is 2.422. The average expected heterozygosity, observed heterozygosity, PIC, matching probability, discrimination power and probability of exclusion values of 90 MHs in the Henan Han population are 0.5788, 0.5851, 0.5039, 0.2608, 0.7392 and 0.2806, respectively. The CMP value of 90 MHs in the study population is less than 10−54, and their CPE value reaches 0.999999999999999923. Moreover, the results of the depth of coverage, allele coverage ratio and noise level indicate that the 90 MH amplification system has well sequencing performance, and the sequencing results are reliable. The results indicate the 90 MHs show higher polymorphisms in the study population. The present panel can be well used in paternity testing and individual identification in the study population and even the populations from EAS.

Maternal ancestry and lineages diversity of the Santander population from Colombia.

Santander, located in the Andean region of Colombia, is one of the 32 departments of the country. Its population was shaped by intercontinental admixture between autochthonous native Americans, European settlers, and African slaves. To establish forensic databases of haplotype frequencies, the evaluation of population substructure is crucial to capture the genetic diversity in admixed populations. Total control region mitochondrial deoxyribonucleic acid haplotypes were determined for 204 individuals born in the seven provinces across the department. The maternal native heritage is highly preserved in Santander genetic background, with 90% of the haplotypes belonging to haplogroups inside A2, B4, C1, and D. Most native lineages are found broadly across the American continent, while some sub-branches are concentrated in Central America and north South America. Subtle European (6%) and African (4%) input was detected. In pairwise comparisons between provinces, relatively high FST values were found in some cases, although not statistically significant. Nonetheless, when provinces were grouped according to the principal component analysis results, significant differences were detected between groups. The database on mitochondrial deoxyribonucleic acid control region haplotype frequencies established here can be further used for populational and forensic purposes.