Biocomputing approach in forensic analysis

In 2009, the National Academy of Sciences (NAS) authored the report Strengthening Forensic Science in the United States: A Path Forward. In it, the Committee expressed the need for accreditation and certification. Accreditation, long recognized by public labs as an important benchmark in quality, was recognized as an important way to standardize laboratories that provide forensic services. Certification can play an important role as a method of oversight in the forensic sciences—something also recommended by the - National Commission on Forensic Science in October 2014. The Complete Guide to the ABC's Molecular Biology is a professional certification examination preparation text for forensic scientists taking the American Board of Criminalistics Examination in Molecular Biology. The book serves as a resource for forensic scientists—who are facing more and more pressure to become certified—to support them in their pursuit of forensic certification. In the years since the NAS report was published, there has been increased discussion of forensic certification requirements. ABC’s Molecular Biology exam is a quality certification, and learning the concepts for it will invariably help any professional working in the field. The book prepares readers in all relevant topic areas, including: accreditation, safety, biological screen principles, anatomy and cell biology, crime scene and evidence handling, concepts in genetics, biochemistry, statistics, DNA evidence, and DNA testing. The book will be particularly helpful for forensic science laboratory technicians, police and investigations professionals, forensic serology and DNA analysts, attorneys, and forensic science students. This study guide follows the guidelines for the exam and presents all the information necessary to prepare individuals to pass the exam.

Forensic sciences are a multidisciplinary science that covers all branches of science for justice. Forensic genetics is one of the sub-branches of forensic sciences. It is a branch of science that contributes to establishing a connection between crime and criminal by using all kinds of biological evidence (blood, semen, saliva, urine, vaginal fluid, hair, hair, sweat, saliva, etc.) and reaching the perpetrator with the genetic information obtained. Serological and immunological tests are used in the identification of body fluids found as evidence at the crime scene. The number of serological tests used in the past and today is limited; not all body fluids can be analyzed routinely. Many of the existing tests are not directly specific to the body fluid but are intended to identify intermediate metabolites. One such example is the urine sample. In the identification of urine, the presence of creatinine and amines in the urine is often used. In addition, these tests require the expenditure of separate consumables to identify each body fluid. For this reason, with the development of technology, in recent years, the use of spectroscopic methods that provide cost-free and easy analysis in the identification of body fluids has increased. Fourier Transform Infrared (FTIR) spectroscopy is one of the spectroscopic methods used to identify body fluids from biological samples found at the crime scene without loss of quantity and without damaging the sample, quickly and without loss of consumables. This study investigated the identification of urine stains obtained from the crime scene with FTIR spectroscopy without using serological materials. Functional groups, which we can express as identification regions, were determined as 13 different distinguishing points in the relevant molecules and their usability in forensic serological analyses was determined.

Two critical issues in forensic science are identifying body fluid traces found at crime scenes and preserving them for DNA analysis. However, the majority of current biochemical tests for body fluid identification, which are applicable at the crime scene, are presumptive and destructive to the sample. Raman Spectroscopy provides a suitable alternative to current methods as a nondestructive, confirmatory, and potentially in field method. Our laboratory has developed a chemometric model for the identification of five main body fluids using Raman spectroscopy. This model was developed using samples obtained from healthy donors. Thus, it is of most importance for the forensic application of the method to validate its performance for donors with diseases that might affect the biochemical composition of body fluids. In this study, the developed method was validated using peripheral blood samples acquired from donors with Celiac Disease, Sickle Cell Anemia, and Type 2 Diabetes. It was shown that the method correctly identified all samples as peripheral blood indicating that no false positives could occur because the blood traces were originated from donors suffering from the diseases.

Body fluid and sex determination at the crime scene are important forensic questions where information can be obtained using various approaches. The standard techniques involved are well established and often utilise cheap, rapid tests to presumptively detect the presence of characteristic proteins and chemicals. However, the relatively poor accuracies of these tests compared to laboratory-based techniques that analyse nucleic acids limits their effectiveness and can lead to inefficient sample triage. This presents a need for novel field-based biomarker detection techniques that are both sensitive and specific. Toehold switches are de novo designed RNA/DNA sequences that contain the genetic motifs necessary for coupled transcription-translation of a reporter gene. Gene expression is repressed in the absence of a specific complementary target “trigger” sequence due to switch hairpin formation. Hybridisation of the trigger to the switch initiates hairpin unwinding and enables downstream gene expression. This specific and sensitive approach has led to toehold switches becoming an emerging platform for bio-detection, primarily in the field of viral RNA detection. This thesis identifies a lack of such applications to forensic science alongside a need for novel field-based DNA detection tools amongst forensic end-users with a market research study. To address these issues, a set of toehold switches were designed in-house for the detection of mRNA sequences specific to blood, saliva, semen, and the sex marker amelogenin. A contemporary qPCR assay was internally validated to act as a performance benchmark. To facilitate in vitro expression of toehold switches without expensive commercial cell-free protein synthesis systems, an Escherichia coli cell lysate was developed and optimised in-house. Gene expression from control plasmids was comparable to a commercial equivalent at 37°C and exceeded it at 29°C, with a shelf-life of approximately 6 – 8 months at -80°C. Toehold switches circuit function was unsuccessful with either system, which suggested an issue with toehold switch design. A screening framework utilising a combined melting curve and in silico thermodynamic analysis approach was devised to highlight high-performance toehold switches. This framework was able to predict the performances of six novel toehold switch designs and recommended designs to be discarded or studied further, but further characterisation is required to assess prediction accuracy. Results throughout are discussed in relation to the needs of forensic scientists and the capabilities of toehold switches as bio-detection tools compared to existing techniques.

In forensic sciences, the serological methods used to determine which body fluid was collected from the crime scene are merely presumptive or labor intensive since they rely on protein detection or on microscopic identification of cells. Given that certain forensic cases may need the precise identification of a body fluid to determine criminal contact, such is the example of a suspected sexual assault of a minor; certainty in the body fluid of origin may depict a precise picture of the events. The identification of loci that show differences in methylation according to the tissue of origin can aid forensic analysts in determining the origin of a DNA sample. The process of DNA methylation occurs naturally in the genome of living organisms and consists in the presence of a methyl group on the carbon 5 of a cytosine, which is typically followed by a guanine (CpG). Analyzing patterns of DNA methylation in body fluids collected from a crime scene is preferential to the analysis of proteins or mRNA since the same extracted DNA used for STR typing can be used for DNA methylation analysis. We have validated and identified loci able to discriminate blood, saliva, semen and vaginal epithelia. In the current study, we have also established the minimum amount of DNA able to provide reliable results using methodologies such as pyrosequencing and high-resolution melt (HRM) analysis for the different markers identified. Lastly, we performed an alternative bioinformatic analysis of data collected using an array that studied methylation in over 450,000 individual cytosines on the human genome. We were able to sort the locations that showed potentially higher methylation differences between body fluids and investigated over 100 of them using HRM analysis. The results of that study, allowed the identification of three new loci able to distinguish blood and two new loci able to distinguish saliva and vaginal epithelia, respectively. The use of DNA methylation patterns to aid forensic investigations started with a publication in 2010, therefore each small contribution such as this work may, similarly to what occured in the biochemistry field, result in the discovery of a method able to put the technology in the hands of forensic analysts.

The biological samples used in forensics can contain DNA which is highly fragmented as a consequence of exposure to any of the numerous degrading factors. Analysis of the sequence or size of the products of Polymerase chain reaction is at present responsible for the analysis of remains of humans in forensics. Despite the effectiveness of protocols based on PCR, there are certain limitations that are presented by the low numbers of copies of the template and the variations that are imposed by the decaying process to the template. The primary aim of this research is to explore the significance of autosomal SNPs in forensic science through the identification of humans at a crime scene. This study provides an exploration of the applicability of autosomal SNPs for the identification of humans at crime scene. This would fill the gap present in the current literature regarding the significance of autosomal SNPs in the identification of humans during crime scene investigation. It will also enable the identification of the criminals involved in several types of the crimes ranging from general theft to rape and sexual assault, murder, and robberies. It will also allow the identification of dead bodies in cases where it is difficult to identify the dead person due to unrecognizable condition of the body. This study will facilitate the improvement of the investigation of crime scene investigators. It will provide a significant way for the incorporation of recent techniques of the molecular genetics into forensics. Reduction in the workload of the crime scene investigators would also occur through the implementation of outcomes of this study into the field of forensic science. There are several studies which have demonstrated the applicability of SNPs in forensic investigations for identifying the humans at crime scene. Several effective and efficient technological systems have been developed by the researchers which are capable of performing analysis of biological samples containing degraded DNA because SNPs can be obtained from these samples. Physical characteristics of the individuals can be predicted through the analysis of SNPs. This can provide significant information about the color of eye, hair and skin of the individuals involved in crime.

Currently, analytical chemistry is more than simply its division into classical and instrumental. It is an interdisciplinary area that involves notions of biology, toxicology, statistics, computer science, and physics, among others. There are several areas of knowledge applied in the development of a chemical analysis, which is configured as all the processes necessary for the identification and quantification of the different components of a sample. When this sample is a trace material from a crime scene, analytical chemistry assumes a central role in the conversion of this sample into material evidence with legal value through consolidated and validated procedures, obtained by exhaustive investigative and methodological studies. The responsibility assumed is in the confidence of the result obtained, which will only be possible with the validation of the method. Although not all methods are perfect, a quantitative determination requires a precise and accurate methodology. Therefore, analytical chemistry is very important to forensic chemistry. Material evidence has a great influence on a trial because it is clothed in technical characteristics, and the expectation is that it will help to unequivocally clarify the truth of the facts. It is this expectation that makes the work of the analytical chemist so important in conducting an analytical procedure for forensic purposes. The result obtained may or may not incriminate someone. Another analytical challenge in forensic analysis is the collection and preparation of a sample that has a criminal trace profile. Such procedures should preserve as much of the criminal evidence as possible. At a crime scene, several samples can be considered evidence: soils, fibers, glass, gunshot residues, explosives, among others. Locard's principle of exchange states that whenever two objects come into contact, an exchange of materials occurs between them and, thus, a connection is established between the suspect and the crime scene or between the suspect and the victim based on the transfer of fragments of the materials. Once again, analytical rigor will play a relevant role in the preservation and experimental conduct of the traces. A failure in the analytical procedure may make it impossible to use a trace as material evidence in a court of law, jeopardizing its use in the conviction of the judge or jury. It is up to the forensic analysts to provide a result with credibility and legal security, i.e., to rigorously follow the analytical protocols. Forensic research is dynamic. One example is the demand for analytical methods that encompass the wide variety of newly emerging psychoactive substances (NPS), formerly known as "designer drugs", which must continually be detected and catalogued. In the Interview in this volume, Dr. Barry Logan tells us about this challenge in his career. I want to register my special thanks to Prof. Dr. Bruno Martinis from the Department of Chemistry of the Faculty of Philosophy, Sciences and Letters of Ribeirão Preto, University of São Paulo (DQ-FFCLRP-USP) of -, who mediated and made possible the interview for BrJAC of one of the most prominent scientists in the area. In his Point of View, Federal Criminal Expert Marcus Andrade tells us about the complexity of forensic chemical analysis of works of art. The analysis of the surface of a painting requires, besides the historical study of the piece, the physical-chemical characterization of its components through an interesting combination of non-destructive analytical techniques such as microscopy, X-ray fluorescence, infrared spectroscopy, among others, which are powerful tools in the process of authenticating a work of art. Nevertheless, the art market, due to the high added value, has attracted organized crime in money laundering in cases of active and passive corruption. Prof. Dr. Jesus Antônio Velho, Federal Criminal Expert and lecturer at the DQ-FFCLRP-USP, addresses the new trends in analytical chemistry for the examination and interpretation of traces of crimes: the determination of the origin of seized drugs (chemical profile), the investigation of document fraud, and the analysis of the evaluation of works of art. Professor Jesus' letter is the result of his long experience in the field and his exceptional insight into the forensic sciences. The author of several books in the field, his text is a gift to us all. We hope readers will enjoy this special edition of BrJAC. Forensic professionals, students, professors, and researchers seek to contribute to criminal justice more broadly through tireless dedication. When we apply forensic analytical chemistry to a crime scene, more than an expert report, we give voice to the victims, who, through their traces, reveal to us the truth of the facts.

Body fluid identification at crime scenes is the first step in the forensic biology workflow, leading to the identification of the perpetrator and/or, in some cases, the victim. Current methods that are regularly used in forensic criminal evidence analysis utilize well-studied properties of each fluid as the foundation of the protocol. Among these approaches, alternative light sources, chemical reactions, lateral flow immunochromatographic tests, and microscopic detection stand out to identify the main body fluids encountered at crime scenes: blood, semen, and saliva. However, these often come with limits for specificity and sensitivity. There is also difficulty with fluid mixtures, environmental degradation, and destruction of the sample by the method used. Other fluids, like vaginal fluid and fecal matter, lack standardized protocols and require innovative ideas for accurate analysis without compromising the sample. Emerging technologies based on molecular methods have been the focus of body fluid research, with emphasis on topics such as mRNA, microRNA, epigenetics, and microbial analysis. Additional information alongside the determination of fluid origin could be an advantage from new molecular techniques, such as the identification of donors from SNP analysis, if regular STR analysis is not possible. Validation studies and the integration of such research have the potential to expand and enhance the laboratory practices of forensic science. This article will provide an overview of the current methods applied in the crime lab for body fluid identification before exploring active research in this field, pointing out the potential of these techniques for application in forensic cases to overcome present issues and expand the variety of body fluids identified.

Determination of illicit and/or abused drugs and compounds of forensic interest in biosamples by capillary electrophoretic/electrokinetic methods

The possibility of using epigenetics in forensic investigation has gradually risen over the last few years. Epigenetic changes with their dynamic nature can either be inherited or accumulated throughout a lifetime and be reversible, prompting investigation of their use across various fields. In forensic sciences, multiple applications have been proposed, such as the discrimination of monozygotic twins, identifying the source of a biological trace left at a crime scene, age prediction, determination of body fluids and tissues, human behavior association, wound healing progression, and determination of the post-mortem interval (PMI). Despite all these applications, not all the studies considered the impact of PMI and post-sampling effects on the epigenetic modifications and the tissue-specificity of the epigenetic marks.This review aims to highlight the substantial forensic significance that epigenetics could support in various forensic investigations. First, basic concepts in epigenetics, describing the main epigenetic modifications and their functions, in particular, DNA methylation, histone modifications, and non-coding RNA, with a particular focus on forensic applications, were covered. For each epigenetic marker, post-mortem stability and tissue-specificity, factors that should be carefully considered in the study of epigenetic biomarkers in the forensic context, have been discussed. The advantages and limitations of using post-mortem tissues have been also addressed, proposing directions for these innovative strategies to analyze forensic specimens.

Chapter 6 - NMR spectroscopy for forensic samples

Drug analysis represents a large field in different disciplines. Plasma is commonly considered to be the biosample of choice for that purpose. However, concentrations often do not represent the levels present within deeper compartments and therefore cannot sufficiently explain efficacy or toxicology of drugs. MALDI-MS in drug analysis is of great interest for high-throughput quantification and particularly spatially resolved tissue imaging. The current perspective article will deal with challenges and opportunities of MALDI-MS drug analysis in different biological samples. A particular focus will be on hair samples. Recent applications were included, reviewed for their instrumental setup and sample preparation and pros and cons as well as future perspectives are critically discussed.

Blood is one of the most important biological evidence found at a crime scene. In a violent crime , the blood sample obtained may belong to the victim, the suspect(murderer) or any other eyewitness. A proper analysis of blood samples obtained at a crime scene may contribute to clarify the circumstances under which the crime would have been committed. The information obtained by studying the blood sample may point the criminal investigation in the right direction and can help solve the crime. Hematology refers to the study of blood and it can play an important tool in analysing the crime. The blood analysis begins with the presumptive tests to confirm that a given sample is blood. Then precipitin technology may be used to find the species to which the blood belongs. Methods like DNA fingerprinting may be used to match the blood at crime scene with the blood of suspect to get a step closer to finding the criminal. We report here few of the analysis of blood that can be done to possibly fasten the process of case solving and find the right criminal.

This book by Ian Burney and Neil Pemberton identifies and explains the origins of modern crime scene investigation (CSI) as a medico-scientific system with networks of institutions, concepts and practices focused on the crime scene as a distinct space ‘bounded conceptually and operationally by explicit rules of practice’ (p. 3). Using homicide as a lens through which to examine this process, the book sets up an important distinction between two paradigms of crime investigation and the sites in which they are performed. Forensic pathology, common since the nineteenth century, studies bodies in a mortuary. But forensic science has a more recent pedigree and a wider sphere of operation: it is concerned with the things found on or around a body (known as trace evidence) and practised at two locations, the crime scene and the laboratory, usually by teams rather than individuals. But forensic pathology and science interact at these three sites and in a fourth, the courtroom; there is thus no simple story of substitution of one for the other. Instead, by the 1950s, conceptual, technical and institutional changes had resulted in the integration of the lone inter-war pathologist into the emergent procedures of CSI.

Processing a crime scene is complex. When scenes are processed well, higher quality specimens can be detected and collected. Inadequately managed scenes increase risk of ineffective investigations and poorer justice outcomes. Government reports from around the world have stated that some crime scene examiners outperform their peers. If processing a crime scene is vital for optimal outcomes, then who should we employ, and train, for this complex and challenging role? What skills do they need? In 2010, the seminal work into the technical and non‐technical skills of top crime scene examiners commenced in Australia. This team used empirical techniques from occupational psychology and business management to identify a cluster of 7 key cognitive, social, leadership skills, and technical/scientific knowledge to develop a profile of top crime scene performers. This work was published in a series of papers between 2012 and 2017. In 2023, the original work was combined with current international empirical findings to build a robust, comprehensive, and more generalizable picture of the holistic skillset of top crime scene examiners. The rationale for developing a skillset is to assist forensic agencies to create targeted recruitment procedures and inform the content of early career training programs for their crime scene teams. With recruitment and training done well, organizations are better placed to attract, develop, and retain personnel with potential to excel in complex roles. When top examiners attend scenes, it is possible the risk of poorer justice outcomes arising from crime scene work could be reduced.This article is categorized under: Forensic Science in Action/Crime Scene Investigation > Crime Scene Examination Forensic Science in Action/Crime Scene Investigation > Education and Formation Forensic Science in Action/Crime Scene Investigation > From Traces to Intelligence and Evidence