1. Introduction
Forensic science, defined, is the application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice system. The importance of forensic science is continuing to grow in the 21st century. This is due to an increase in technology that allows the identification and/or comparison of evidence that in the past would have been bypassed or falsely interpreted. Forensic science is constantly evolving as is the use in the criminal justice system. Essentially, the foremost reason that forensic science is so important is because it provides crucial scientific evidence for use in public courts of law using the scientific method. Forensic science provides evidence to resolve legal issues by applying scientific methods and processes. Essentially, it is science applied to the law. It is also used to describe all the scientific and technical work which is used in the investigation and prosecution of crime. Science is employed in the service of the law in order to provide a neutral, scientific analysis of physical evidence for use in the courts of law. This can be separated into two categories: I. Criminalistics – is the application of various sciences to answer questions relating to examination and comparison of biological evidence, trace evidence, impression evidence (such as fingerprints), firearms, and other evidence in criminal investigations. II. Legal medicine – encompasses vast and varied aspects of medicine for the purpose of serving the legal system. This would include pathology, psychology, psychiatry, and toxicology with bridges to various other sciences such as entomology (for the estimation of time of death) and anthropology. The work in this category might or might not be for criminal purposes.
1.1. Definition of Forensic Science
The scope of forensic science has grown enormously in recent years. This has been accompanied by significant increases in public awareness prompted by sensationalized media accounts of its applications. Shows such as CSI (Crime Scene Investigation) have captured the public’s imagination with cutting-edge technology and techniques used to solve mysterious and heinous crimes. Unfortunately, this portrayal is not always completely accurate. It is important to understand the definitions and limitations of forensic science in each of its specific disciplines. This brief overview is designed to help clarify precisely what constitutes forensic science, hopefully preventing the inflated media portrayal from becoming reality. It will also touch on the various forensic disciplines and explain some of the problems and criticisms that have been raised about forensic science within the criminal justice system.
1.2. Importance of Forensic Science in Criminal Investigations
Forensic science is a suitable subject to be used in conjunction with the New Zealand curriculum. This subject incorporates biology, chemistry, physics, and earth and space science. This, in turn, allows students to develop an understanding of the different scientific ideas and processes. Forensic science creates global citizens who are able to interpret media and reports and question the opinions being brought to the table. This is a major desirable of the New Zealand curriculum as it allows students to think critically and reflect on their own ideas. Students will be able to demonstrate that they are informed thinkers, who think critically and creatively about complex issues. This will result in a student who is able to make justified decisions in response to information at local, national, and global levels.
Forensic science is the application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice system. It is a science which is used for the purpose of identifying the perpetrator of a crime or to clear the innocent from any accusations. So, it can be used to establish the guilt or innocence of an accused. Forensic science employs both inductive and deductive reasoning in order to reach a scientific conclusion concerning whether the evidence is from a suspect and whether it connects the suspect with the victim or crime scene.
1.3. Historical Overview of Forensic Science
Forensic science is often described as science applied to the law. It is largely multidisciplinary, and its findings can have a great impact in the criminal justice process. Identification is the first and the most important step in forensic investigations. Since the advent of DNA testing in the mid-1980s, biological specimen identification has been largely based on the results of the analysis of a DNA profile. Prior to this, however, biological specimen identification was largely dependent on a comparison of ante mortem and post mortem data to determine the evidence of life. For example, healing fractures can only be determined by the presence of new bone growth, and differential diagnoses of disease are largely dependent on the histological or pathological findings on a specific organ. Anthropologists, medical practitioners, and pathologists have been developing methods to diagnose diseases and trauma more clearly for centuries, and this has led to the development of various physical and biological methods that can be applied to forensic investigations. The analysis of teeth and skeletal remains can give an indication of an individual’s identity, age, and even provide information on the cause of death. High-power DNA analysis methods have increased the precision at which we can determine the identity of an individual, and studies in molecular biology and biochemistry are constantly being done to improve these methods. DNA analysis and mathematics can now also be used to calculate the probability of an event such as paternity or the probability of a certain person being a certain age given a specific set of data. This type of analysis, known as Bayesian statistics, has found its way into the legal system and is now used in the evaluation of evidence from eyewitnesses and to determine the outcome of criminal trials.
2. Forensic Science Techniques
2.1. Crime Scene Investigation
2.1.1. Collection and Preservation of Evidence
2.1.2. Documentation and Sketching of Crime Scenes
2.1.3. Photography and Videography in Crime Scene Investigation
2.2. Fingerprint Analysis
2.2.1. Classification and Comparison of Fingerprints
2.2.2. Automated Fingerprint Identification Systems (AFIS)
2.2.3. Latent Fingerprint Development Techniques
2.3. DNA Profiling
2.3.1. Extraction and Isolation of DNA
2.3.2. Polymerase Chain Reaction (PCR) in DNA Profiling
2.3.3. Short Tandem Repeat (STR) Analysis
2.4. Ballistics Analysis
2.4.1. Firearms Identification
2.4.2. Bullet and Cartridge Case Examination
2.4.3. Gunshot Residue Analysis
3. Forensic Science in Forensic Pathology
3.1. Role of Forensic Pathologists in Death Investigations
3.2. Autopsy Procedures and Techniques
3.3. Determination of Cause and Manner of Death
3.4. Forensic Toxicology
3.4.1. Analysis of Drugs and Poisons in Postmortem Samples
3.4.2. Interpretation of Toxicology Results
3.4.3. Role of Forensic Toxicologists in Death Investigations
4. Forensic Science in Digital Forensics
4.1. Computer Forensics
4.1.1. Data Recovery and Analysis from Digital Devices
4.1.2. Cybercrime Investigations
4.1.3. Network Forensics
4.2. Mobile Device Forensics
4.2.1. Extraction and Analysis of Data from Mobile Devices
4.2.2. Cell Site Analysis
4.2.3. Forensic Examination of Social Media and Messaging Apps
5. Forensic Science in Forensic Anthropology
5.1. Role of Forensic Anthropologists in Human Identification
5.2. Skeletal Analysis and Reconstruction
5.3. Age, Sex, and Ancestry Estimation from Skeletal Remains
5.4. Forensic Odontology
5.4.1. Dental Identification in Forensic Cases
5.4.2. Bite Mark Analysis
6. Forensic Science in Forensic Entomology
6.1. Use of Insects in Estimating Time of Death
6.2. Insect Collection and Preservation Techniques
6.3. Forensic Entomology in Decomposition and Crime Scene Analysis
7. Forensic Science in Forensic Psychology
7.1. Psychological Profiling and Behavioral Analysis
7.2. Evaluation of Competency and Sanity
7.3. Eyewitness Testimony and Memory Recall
8. Emerging Trends in Forensic Science
8.1. Advancements in DNA Technology
8.2. Artificial Intelligence in Forensic Analysis
8.3. Forensic Botany
8.4. Forensic Geology
8.5. Forensic Linguistics
9. Conclusion