Forensic Science: Revealing the Clues

Abstract

Forensic science is the discipline concerned with the systematic examination and interpretation of evidence obtained from crime scenes, employing a range of scientific methodologies. The field of forensic science comprises a range of specialised sub-disciplines within the field of criminal investigation plays a distinct role in the complex process of piecing together evidence, contributing to the creation of a cohesive narrative. In the field of forensic medicine, the significance of forensic science is further accentuated. The field of forensic science is of greatest importance in the context of postmortem examinations, as these examinations are carried out with the primary objective of determining the cause and manner of death in deceased individuals. Autopsies, which are fundamental to the field of forensic medicine, are performed in order to determine the physiological and pathological characteristics of a deceased individual. Forensic pathologists, in conjunction with forensic scientists, engage in thorough examinations utilising a variety of equipment, including microscopes, advanced imaging techniques, digital histopathological techniques, leveraging their substantial medical expertise. The collaboration between multiple disciplines ensures a holistic comprehension of the deceased individual’s state, revealing key observations regarding the factors that contributed to their death. The chapter will be describing the significance of “Forensic Science” in the field of forensic medicine and its future scope.

1. Introduction

As a multifaceted subject that exists at the intersection of science and criminal justice, forensic science plays an important part in the process of investigating crimes and bringing victims the justice they deserve. Forensic science is the application of scientific principles and methods to the investigation of crime and the administration of justice [1]. Forensic science comprises a broad spectrum of disciplines and use scientific methodologies and procedures to analyse and interpret evidence in the context of criminal investigations and judicial proceedings. The basic objective of forensic science is to collect, examine, and evaluate tangible evidence in order to establish factual information or offer expert testimony within the context of legal processes. Forensic science encompasses a diverse array of scientific disciplines and plays a crucial role in the resolution of criminal cases, examination of evidence recovered from autopsies, the identification of potential perpetrators, and the maintenance of a fair and just legal system. The history of forensic science reflects the continuous development of techniques and methods for solving crimes, identifying victims, and ensuring justice. It has transformed from rudimentary practices into a highly specialised and multidisciplinary field that plays an indispensable role in modern criminal investigations and the legal system. During the Middle Ages in Europe, methods of trial by ordeal, such as dunking or firewalking, were used to determine guilt or innocence. The concept of “forensic medicine” began to emerge with the work of early medical practitioners, who conducted post-mortem examinations to establish causes of death [2]. The field of forensic science is of greatest importance in the context of postmortem examinations, as these examinations are carried out with the primary objective of determining the cause and manner of death in deceased individuals. Postmortem examinations, commonly referred to as autopsies, play a pivotal role in resolving inquiries pertaining to suspicious deaths, accidents, mysterious death, and various forensic investigations by providing a wide range of tools and techniques that can be used to assist forensic pathologists in their work [2]. Forensic pathologists are physicians with specialised training in the investigation of death, and they perform postmortem examinations on deceased people in order to ascertain the cause of death as well as the manner in which they passed away [1]. In recent years, there have been significant improvements and novel ideas in postmortem examination as a result of constant pursuit of advancement and the incorporation of cutting-edge technologies and approaches. Forensic Medicine is an application of medical knowledge for the purpose of law both civil and criminal cases [3]. The inception of forensic medicine can be historically situated in ancient civilizations. One instance of arsenic poisoning-induced homicide was recorded by the Roman statesman Cicero as early as 44 B.C. Postmortem examinations were a customary practice in ancient China, serving the purpose of ascertaining the cause of death and dispensing justice. Prominent individuals such as Sir Bernard Spilsbury and Rudolf Virchow (The father of modern pathology) played an essential role in the development of forensic medicine and pathology [4]. Forensic medicine can be divided into a number of sub branches. Forensic pathology deals with morbid anatomy, pathology of injury and different aspects of death with their medicolegal significance. Forensic odontology where the ability of dentistry is undertaken when the question of identification and interpretation of bite marks arise [5]. Forensic dentists analyse dental records and the condition of teeth to establish the identity of the deceased when other means of identification are not possible. Dental examinations can also provide information about bite marks and dental injuries that may be linked to the cause of death. A number of factors are found in the teeth that are utilised for identification purposes. Forensic anthropology, studied of bodily shape and skeletal formation in legal sense and also for the identification purposes [5]. In cases where bodies are badly decomposed or skeletal remains are all that’s left, forensic anthropologists use their expertise to identify the deceased, determine age, sex, ancestry, and potential trauma or disease-related factors.

2. Relationship between forensic science and forensic medicine

Forensic science and forensic medicine are two closely related fields that share a common objective to provide expert analysis and evidence that assists in legal investigations and the administration of justice. Forensic scientists and forensic pathologists often collaborate on cases. For example, when a deceased person is found at a crime scene, forensic scientists may collect physical evidence, such as hair, fibres, or biological samples. This evidence can then be handed over to forensic pathologists who, during an autopsy, examine the body for injuries, signs of poison, or other medical conditions. This collaboration can help establish a more comprehensive understanding of the circumstances surrounding a death or a crime.

3. Role of forensic science in post-mortem examinations

Forensic science plays an important part in post-mortem investigations which are conducted on deceased individuals to determine the cause and manner of death by providing a variety of modern tools, techniques, and expertise essential to systematically gather, analyse, and examine various types of evidence [6]. Often, a prevalent inquiry arises: “What is the importance of investigating the death of an individual who is beyond assistance?” [3]. Although the deceased cannot directly profit from such a study, its importance exists in its potential to help the living and future generations [7]. It is crucial to establish the cause of death in forensic aspect that highly values the sanctity of life. During circumstances of unexpected fatal accidents, the forensic pathologist assumes a crucial position in determining the cause of death. The cooperation among forensic scientists, forensic pathologists, and medical examiners is essential in conducting these examinations, ensuring thorough examination of each case and helps in revealing the facts.

3.1 Cause of death determination

In forensic postmortem examinations, the determination of the cause of death is a critical aspect. Forensic pathologists, who are medical doctors specialised in examining deceased individuals, thoroughly investigate the body to identify the underlying condition or circumstances that led to the person’s death [1]. The cause of death can fall into several broad categories, and it’s essential to establish it accurately for legal and investigative purposes. Following below are common causes of death identified during forensic postmortem examinations:

1. Natural causes: These are deaths that result from diseases or medical conditions. Common natural causes include:

   1. Cardiovascular diseases (e.g., heart attacks, strokes)

   2. Respiratory diseases (e.g., pneumonia)

   3. Infectious diseases (e.g., sepsis)

   4. Neurological conditions (e.g., epilepsy, brain tumours)

   5. Metabolic disorders (e.g., diabetes)

2. Trauma and injuries: Deaths due to external physical forces or injuries are categorised as traumatic deaths [6]. Examples include:

   1. Blunt force trauma (e.g., from falls or assaults)

   2. Sharp force trauma (e.g., stabbings, gunshot wounds)

   3. Asphyxia (e.g., strangulation or suffocation)

   4. Burns or electrocution

   5. Motor vehicle accidents

3. Toxicological causes: These involve deaths resulting from exposure to toxic substances, drugs, or chemicals:

   1. Poisonings (e.g., overdose of drugs, exposure to toxic chemicals)

   2. Drug-related deaths (e.g., opioids, stimulants)

   3. Alcohol intoxication

4. Asphyxiation: Deaths related to a lack of oxygen can be due to various circumstances:

   1. Drowning

   2. Strangulation

   3. Inhalation of noxious gases

   4. Choking on foreign objects

5. Environmental causes: These include deaths related to environmental factors:

   1. Hypothermia or hyperthermia

   2. Lightning strikes

   3. Exposure to extreme weather conditions

6. Infectious diseases: In some cases, infectious diseases can lead to death, especially if they are not properly diagnosed and treated.

3.2 Manner of death

Forensic science helps establish the manner of death, which falls into five main categories: natural, accidental, suicide, homicide, or undetermined [8]. The examination involves the analysis of medical and physical evidence, as well as the consideration of circumstantial factors to determine the most likely manner of death.

1. Natural: A death is classified as “natural” when it results from a disease or medical condition, typically of a non-violent or non-traumatic nature [6, 7].

2. Accidental: Accidental deaths occur when a person dies as a result of an unintentional or unexpected event [8]. Examples of accidental deaths include motor vehicle accidents, falls, drug overdoses, electrocutions, and accidental drownings. These deaths are typically not the result of deliberate actions.

3. Suicide: Self-inflicted injuries or poisoning may be identified as the cause of death.

4. Homicide: When the postmortem examination suggests that the death was a result of someone else’s actions, it is classified as a homicide.

5. Undetermined cause: In some cases, despite thorough examination, it may not be possible to establish a definitive cause of death. These cases may be classified as “undetermined” or “unascertained.”

3.3 Toxicology

Toxicological analysis plays a vital role in postmortem examinations, helping forensic experts determine whether toxic substances or drugs contributed to a person’s death [9]. Toxicological findings help establish whether substances contributed to or caused the death. It involves the testing of biological samples, such as blood and urine, to detect the presence of drugs, alcohol, poisons, or toxins.

1. Identification of toxic substances: Toxicological analysis helps identify the presence of toxic substances in the deceased’s body, such as drugs, alcohol, prescription medications, poisons, or chemicals [9]. This is crucial for understanding whether the individual was exposed to substances that could have played a role in their death.

2. Determining the cause of death: In cases where toxic substances are identified, toxicological analysis helps establish whether these substances were the primary cause of death or contributed to it. For example, an overdose of a drug or alcohol poisoning may be identified as the primary cause of death.

3. Quantifying drug levels: Toxicological testing quantifies the concentration of substances in the body, providing information about the amount of a drug or toxin present. In cases involving accidents or fatalities, toxicological analysis can determine whether the deceased was under the influence of drugs or alcohol at the time of the incident.

4. Identifying illicit substances: Illicit drugs, such as opioids, cocaine, or methamphetamines, can be detected through toxicological analysis. These findings can be relevant in drug-related deaths or cases of substance abuse.

3.4 Injury analysis

In forensic postmortem examination, the analysis of injuries is a fundamental aspect of determining the cause of death and understanding the circumstances surrounding a fatality. Within the realm of law, a wound refers to a damage that disrupts the integrity of the skin [10]. Forensic pathologists and experts employ these methods to identify, document, and interpret injuries, providing a comprehensive picture of what transpired prior to death [2]. The information gleaned from injury analysis not only contributes to the pursuit of justice in homicide cases but also aids in accident investigations, suicide determinations, and the prevention of future harm, particularly in cases of child abuse.

Injury analysis begins with the identification and thorough documentation of all injuries present on the deceased’s body. These can range from contusions, lacerations, abrasions, and gunshot wounds to fractures, stab wounds, burns, and more [3]. Forensic pathologists meticulously examine these injuries, noting their location, size, shape, depth, and associated characteristics to determine the type of trauma that occurred [10]. For example, the distinct patterns of bruising and fractures can help differentiate between blunt force trauma, sharp force trauma, and gunshot injuries.

It can also enable experts to estimate the force and direction of an injury, which can be vital in homicide investigations. For instance, the direction of a gunshot wound’s trajectory can provide information about the position and proximity of the shooter, helping to corroborate or refute witness testimonies. The examination of injuries also includes assessing their age and healing status. This can help determine whether injuries were recent or occurred some time before death, shedding light on potential patterns of abuse, neglect, or repeated trauma.

3.5 Histopathology

Histopathological examination involves the microscopic analysis of tissue samples collected from various organs and body parts of the deceased individual including the heart, lungs, liver, kidneys, brain, and others [11]. The selection of specific tissues for examination depends on the circumstances and findings of the macroscopic autopsy. This examination provides detailed information about the condition of the tissues and organs, helps uncover underlying diseases or injuries where cause of death is unknown, and contributes to the overall determination of the cause and manner of death [12].

3.6 Entomology

Forensic entomology is a specialised branch of forensic science that leverages the study of insects to provide essential information in criminal investigations and legal matters [5]. Insects are the first responders to a corpse, and their colonisation patterns can provide crucial information about when death occurred. By identifying the types of insects present, their life stages, and environmental conditions, entomologists can make reasonably accurate estimates of the post-mortem intervals which is the time that has elapsed since a person’s death, the manner of death, aiding in the pursuit of justice [13]. Forensic entomology can be utilised to determine whether the death occurred at the scene of the body’s discovery or whether the body was transported after death. Specific insect species are drawn to different environments and microclimates, and their existence can provide clues about the location of death.

4. Advancements in forensic medicine

The capacities and accuracy of post-mortem examinations have been greatly improved by advancements in forensic medicine, revolutionising the area of forensic science and its uses in criminal investigations and legal proceedings. Among the noteworthy developments are given below.

4.1 Minimally invasive autopsy techniques

The area of post-mortem investigations has undergone a revolution with the advent of minimally invasive autopsy techniques, such as “Virtopsy” meaning virtual autopsies that make use of magnetic resonance imaging (MRI) and computed tomography (CT) scans [14]. In order to conduct thorough investigations without the necessity for traditional invasive autopsies, forensic pathologists can now visualise interior organs, tissues, and pathological alterations in three dimensions thanks to non-invasive imaging technologies [14]. This development improves the acceptance and accessibility of post-mortem exams by reducing the invasiveness and time needed for operations while also making it easier to preserve the body for cultural or religious reasons.

4.2 Automated histological analysis

Digitalization and automation have revolutionised post-mortem examinations by enabling quick and accurate evaluation of tissue samples and histopathological alterations. Daisuke Komura and Shumpei Ishikawa reviewed about the machine learning methods in histopathological imaging technologies to analyse disease processes, cellular structures, and tissue shape quickly and efficiently [15]. This helps to identify abnormal findings more quickly and streamlines the diagnosis process. Forensic pathologists can precisely analyse and categorise histology data by utilising sophisticated image analysis algorithms and machine learning approaches [15]. This helps with the exact identification and characterisation of various pathological diseases and cellular abnormalities.

4.3 Advanced imaging technologies

The visualisation and analysis of post-mortem specimens have been completely transformed by the incorporation of advanced imaging technologies, including multispectral imaging, three-dimensional (3D) imaging, and sophisticated microscopy techniques. In a study conducted by Shereen Ahmad et.al mentioned about the Postmortem multislice computed tomography (PMCT) technique for autopsies which is a Modern imaging technology and a non-invasive technique which provide forensic pathology experts to improved clarity and accuracy by visualising microscopic tissue structures, lesions, cellular abnormalities, and wound path visualisation in high-resolution and detail [16]. These cutting-edge imaging technologies enable forensic pathologists to perform exhaustive and comprehensive analyses, making it easier to precisely identify and document important forensic evidence and pathological findings. PMCT can be used as a post-mortem alternative or as an autopsy complement to capture multidimensional data and produce accurate anatomical reconstructions (Figure 1) [16].

Figure 1.

Gunshot injuries of the head. A PMCT-3D-volume rendering image showing a comminuted fracture (F) opposite the exit in the occipital bone. b MDCT-3D-volume rendering image showing the entry wound of firearm injury (I) in the right temple and multiple fracture (F) of the skull bone in the right sphenoid wing, right temporal, right frontal, and right occipital bone [15].

4.4 Forensic molecular pathology

Molecular abnormalities, disease markers, and genetic mutations can now be identified through post-mortem examinations thanks to the development of forensic molecular pathology techniques such as genetic profiling and next-generation sequencing (NGS) [17]. Shahad A Alzahrani et al. reviewed to highlight the genetic causes of sudden death with the help of postmortem genetic testing (molecular autopsy) technique [18]. It helps forensic experts to identify genetic predispositions and familial disease risks by incorporating molecular pathology analyses into post-mortem investigations. This allows for the discovery of critical information regarding the genetic basis of pathological conditions and hereditary diseases. In the context of forensic medicine, the use of NGS technology facilitates thorough genomic analysis and the identification of particular genetic variants and mutations, which helps with the accurate diagnosis and classification of genetic and hereditary disorders. Dewar et al. undertook an investigation to determine the genetic disorders in autopsy cases by utilising postmortem genetic testing to investigate cases of sudden unexplained death (SUD) [19].

4.5 Integrated data analysis and forensic databases

Forensic databases and integrated data analysis platforms have made it easier to gather, manage, and analyse post-mortem data. This has made it possible to retrieve, compare, and interpret data for forensic investigations and research projects more quickly and efficiently. A comprehensive and interdisciplinary approach to post-mortem examinations and forensic analyses is fostered by these cutting-edge data management systems, which give forensic professionals the ability to compile and integrate a wide range of post-mortem data, including pathological findings, toxicological results, genetic profiles, and case histories. Forensic experts can carry out thorough and methodical assessments of forensic evidence by utilising advanced data analysis tools and forensic databases. This makes it easier to accurately interpret and integrate multidimensional data sets for forensic investigations and expert testimony in court cases.

4.6 Forensic virtual reality and simulation

The training and teaching of forensic pathologists, medical examiners, and investigators has been completely transformed by the advent of forensic virtual reality (VR) and simulation technologies [20]. Forensic virtual reality and simulation platforms, through the simulation of diverse post-mortem scenarios, crime scene reconstructions, and forensic analyses, provide forensic professionals with an immersive and dynamic learning environment that fosters the development of their investigative techniques, critical thinking skills, and practical skills in a controlled and simulated forensic setting [20]. In Switzerland, juries were involved in a realistic scenario where radiologists and forensic professionals utilised Virtual Reality headsets to produce postmortem imaging, imitating trauma mechanisms and crime scenes for presentation in the court [21]. The virtually reconstructed crime scene based on 3D virtual autopsy as shown in Figure 2.

Figure 2.

3D virtual reality reconstruction of crime scene using postmortem imaging. Picture courtesy Christoph Fischer [21].

4.7 Routine photography and its significance in post-mortem examination

In order to support the advances in post-mortem examinations, routine injury photography is a crucial component of forensic medicine. It allows for the thorough documentation, analysis, and interpretation of traumatic injuries, wound patterns, and physical trauma. By employing sophisticated photography techniques to document injuries in a methodical manner, forensic experts can obtain comprehensive visual records of external trauma, anatomical alterations, and wound attributes. This allows for the accurate and dependable evaluation of injury patterns and their association with the cause and mode of death. When regular injury photography is connected to the above mentioned developments in forensic medicine, the following outcomes are seen:

1. Comprehensive documentation and visualisation: Traumatic injuries and anatomical changes can be comprehensively documented and visualised through the use of routine photography of injuries in conjunction with cutting-edge imaging technologies and digital visualisation tools. Through the integration of sophisticated photography techniques with multispectral imaging, three-dimensional (3D) imaging, and high-resolution microscopy, forensic experts can effectively capture precise and detailed visual depictions of injuries, improving the lucidity and accuracy of injury reports and streamlining the thorough examination and interpretation of traumatic findings in the context of post-mortem examinations.

2. Enhanced injury analysis and pattern recognition: The analysis and recognition of injury patterns and trauma features are improved by the combination of automated histology analysis, forensic virtual reality technologies, and routine photography. Forensic experts can perform in-depth analyses of injury patterns, wound morphology, and tissue characteristics by combining meticulous photographic records with automated image analysis algorithms and virtual reality simulations. This makes it easier to precisely identify and classify traumatic injuries and their forensic significance in the context of post-mortem investigations.

3. Integrative data management and injury profiling: The methodical correlation and interpretation of photographic evidence with genetic and molecular findings is made possible by routine photography of injuries combined with forensic databases and molecular pathology analyses. Forensic experts can perform multidimensional data integration and comprehensive injury profiling by integrating photographic documentation into comprehensive forensic databases and integrated data analysis platforms. This promotes an integrated approach to injury assessment and interpretation in the context of post-mortem examinations and forensic analyses.

4.8 Microbial forensics

In order to determine the origins, pathways of transmission, and potential roles of microorganisms—including bacteria, viruses, and fungi—in criminal investigations and bioterrorism incidents, forensic scientists have developed a specialised field known as “microbial forensics.” [22]. Robinson et al. reviewed about the potential applications of microbiomics in forensic science which includes geolocation, personal identification, biological sex determination [23], cause and manner of death, postmortem interval investigations majorly by thanatomicrobiome [24] and trace evidence analysis by studying the presence of bacterial growth on objects and surfaces [25] as shown in Figure 3 [26]. The following results can be shown by combining microbiological forensics with improvements in post-mortem examinations.

1. Identification and profiling of pathogens and disease-causing microorganisms: Identification and profiling of pathogens and disease-causing microorganisms linked to infectious diseases and biological threats is made possible by the integration of microbial forensics into post-mortem investigations and damage reporting [27]. Using sophisticated molecular pathology methods and microbial genomic analyses, forensic experts can pinpoint and describe particular microorganisms, making it easier to pinpoint infectious agents, their routes of transmission, and their possible roles in the onset and course of pathological conditions and disease states.

2. Interpretation and examination of biological evidence: Microbial forensics can be integrated with extensive data management systems and injury analysis platforms to facilitate the interpretation and analysis of microbial and biological evidence in the context of post-mortem examinations and injury. Forensic experts can perform multifaceted analyses of biological evidence by combining microbial data with extensive injury profiles and forensic databases. This allows for the integration and correlation of microbial signatures with trauma characteristics, pathological findings, and injury patterns, improving the comprehensive interpretation and forensic significance of microbial evidence in the context of criminal investigations and post-mortem analyses.

3. Epidemiological investigations and outbreak analysis: The conduct of epidemiological investigations and outbreak analyses of naturally occurring infectious diseases is facilitated by the integration of microbial forensics [28]. Investigators will also use the actual geographical location of the crime and evidence obtained from other forensic disciplines (e.g. PMI estimations) to reconstruct the crime and identify the persons involved [24]. This allows for the thorough assessment and documentation of microbial transmission patterns and disease dissemination pathways. Forensic experts can examine and visualise the dynamics of disease outbreaks, the spread of infectious agents, and the connections between microbial transmission and traumatic injuries by integrating microbial data with advanced imaging modalities and injury documentation [29]. This allows for a thorough understanding of the forensic and epidemiological implications of microbial evidence in the context of post-mortem exams and injury investigations (Figure 4).

Figure 3.

Possible sources to be identified with the help of microbial forensics.

Figure 4.

Implication of the microbial forensics in post-mortem examination.

5. Conclusion

The utilisation of forensic science is essential to the smooth functioning of the criminal justice system. By conducting thorough analyses of evidence collected from diverse locations, such as crime scenes, forensic scientists aim to generate unbiased conclusions that aid in the investigation and legal proceedings associated with criminals, or to clear individuals who have been unfairly accused. Forensic science is especially important in the context of post-mortem examinations, also known as autopsies. Deceased individuals undergo these autopsies with the primary objective of ascertaining the cause and manner of demise. By providing the instruments and knowledge required to collect, analyse, and interpret various forms of evidence, forensic science aids medical examiners and forensic pathologists in their investigations. Integration of multiple forensic science disciplines is essential for a thorough and accurate examination of the case involving a deceased person.

Conflict of interest

The authors declare no conflict of interest.