This paper examines the critical role of forensic science and technology in modern criminal investigations. It surveys the nature of physical evidence collection, preservation, and analysis, then evaluates major forensic disciplines including pattern evidence (fingerprinting, tire and footprints), ballistics, DNA analysis, anatomical forensics with forensic entomology, and computer forensics. Each method is explored for its contribution to identifying suspects and victims, establishing timelines, and providing courtroom evidence. The paper demonstrates how forensic science has evolved to address diverse crime types, from violent offenses to digital crimes, and emphasizes the reliability and accuracy these techniques bring to law enforcement.
Criminal investigations have evolved significantly since the inception of law enforcement in modern society. A major driver of this evolution has been the increasing complexity of forensic science and analysis as applied within criminal investigations. Forensics helps criminal investigations uncover, process, and analyze data relating to certain crimes being investigated. These investigations may involve violent or physical crimes, such as murder, or financial and electronic crimes. With such varied crimes being committed today, the use of forensics within law enforcement is multi-faceted and includes numerous sub-fields depending on the nature of each individual crime and circumstance.
Forensics relies fundamentally on the uncovering, preservation, and analysis of physical and digital evidence. In criminal investigations, evidence is crucial to prove that criminal events occurred and to prove a suspect's involvement with particular crimes. Evidence "can take any form. It can be as large as a house or as small as a fiber. It can be as fleeting as an odor or as obvious as the destructive results at the scene of an explosion" (Fisher & Fisher, 2012, p. 1). Evidence is incredibly varied in what constitutes reliable evidence, and its nature depends on the specific crime. Thus, forensics must be flexible enough to collect and analyze evidence in its wide variety of forms.
According to the research, "physical evidence can prove a crime has been committed or establish key elements of a crime" (Fisher & Fisher, 2012, p. 1). Forensics works to classify the source of evidence so that it can be interpreted by law enforcement in relation to the crime in question. Forensics additionally works to collect and preserve evidence for later use in court. Once evidence is found at a crime scene or elsewhere, it must be meticulously categorized, labeled, and stored for later analysis. Any exposure to external stimuli may compromise the legitimacy and worth of the evidence. Once evidence has been collected, forensic scientists and specialists make educated conclusions regarding its nature. "Specially trained personnel—forensic scientists, criminalists, forensic technicians, or identification technicians—examine physical evidence collected at crime scenes. These specialists prepare reports and testify in court as expert witnesses" (Fisher & Fisher, 2012, p. 14). Forensics as a field encompasses the collection and analysis of all types of evidence.
One of the oldest and most trusted forensic methods is fingerprinting. The human fingerprint is completely unique for each individual, and patterns of prints left at crime scenes can be very convincing evidence in court. Prints are uncovered through dusting with a special powder that exposes oils from the hand and fingers. Forensic investigators use cellophane tape or printing ink to copy fingerprints found at the scene for later analysis. Once collected, these prints can be scanned into a computer and run through an Automated Fingerprint Identification System, which have "revolutionized the way police departments search for latent prints for matches" (Fisher & Fisher, 2012, p. 117). These are nationwide databases that hold records of individuals fingerprinted by law enforcement and regulatory agencies. Previously, law enforcement officials had to manually search through printed catalogues, a process significantly slower than the specialized computer-generated searches that now take mere minutes to complete. Forensic scientists match patterns to prints left at crime scenes to identify potential suspects who may have been present when the crime took place. Highly accurate print-mapping programs help forensic scientists distinguish more characteristics in partial or damaged prints left at scenes, making investigation processes run much smoother. Similar techniques are also used for palm and footprints.
Other types of pattern evidence can also be collected through forensic investigation. Tire marks, shoe impressions, tool marks, and other physical markers can be uncovered, preserved, and analyzed using forensic science. Footprints and tire marks are most often found outside, making it important for forensic teams to preserve and copy the evidence quickly before it is destroyed by weather and the elements. Such marks are often preserved through casting and photography, which can then be analyzed using computer software and geometric analysis. The main purpose of collecting and analyzing pattern evidence is to link a specific pattern to an object connected to a victim or suspect, strengthening the connection and supporting conclusions about the crime.
In cases of violent offenses like attacks and murders, finding and analyzing the weapon used is a crucial goal of forensics in assisting criminal investigations. In shooting cases involving firearms, forensic specialists work with ballistic evidence to match firearms to shell casings and bullets left at the scene. According to the research, "ballistics and the trajectory of projectiles recovered will be of importance" in helping establish how a violent incident occurred reliably enough to stand in court (Douglass & Burgess, 2011, p. 142).
Ballistics refers to the markings or rifling left on bullets and shell casings. These markings are unique to each firearm and can be used to identify what particular weapon was used in specific crimes. If the markings on a shell casing left at the scene match the markings in a weapon found in a suspect's home or possession, this creates a strong connection that can hold up in court. However, "customized suppressors, handguns, or other instruments" designed to stifle sounds or tamper with rifling marks can make analysis of ballistic evidence difficult and require a multi-faceted forensic approach using combinations of different analytical techniques (Douglass & Burgess, 2011, p. 134). Thus, modern forensics aims not only to identify markings but also to increase the likelihood that markings remain identifiable even when suppression mechanisms have been used.
DNA analysis is a crucial part of modern forensic science. The research states that "since 1985, DNA typing of biological material has become one of the most powerful tools for personal identification in forensic medicine and criminal investigations" (Benecke, 1997, p. 181). DNA is incredibly reliable, and since the inception of DNA analysis, forensics has become a much more powerful force in identifying suspects and victims, even years after a crime has occurred. DNA analysis functions essentially like "genetic fingerprinting" (Benecke, 1997, p. 181). Each individual has a unique genetic makeup, just like their fingerprints. DNA analysis focuses on exposing and identifying genetic markers so they can be linked to suspects or victims through comparison with national databases. The process is incredibly complex and continues to become more reliable as new technologies are introduced.
According to the research, "DNA testing uses the statistical occurrence of discrete pieces of genetic material or alleles. These alleles have different frequency values developed from population databases" (Fisher & Fisher, 2012, p. 7). From biological material, DNA patterns and pattern fragments can be lifted and used to determine identification. Because DNA is so specific as a marker for individual identity, it is highly reliable, with nearly a 99% probability of accuracy in identification.
DNA is used to determine identity and can be gathered from numerous sources. It can identify a victim or a suspect. Blood, semen, or other biological material such as skin cells all provide DNA for forensic analysis. It can be taken from living victims, deceased victims, clothing, or hard surfaces where biological material may have been left. Modern technology has greatly increased the ability for forensics to extract DNA from material. Today, more complex analytical procedures allow DNA to be taken from surfaces that have been cleaned or from material much older than typical samples required in traditional DNA typing procedures.
Along with DNA analysis, forensic scientists also conduct anatomical analyses, where a victim or body is the focal point of the forensic investigation to help provide physical evidence. Anatomical analysis is crucial for determining how a crime occurred, especially regarding cause of death. Essentially, "the science of forensics draws upon a body of knowledge gained from observation, experiment, and experience, and applies that understanding to questions of interest within the legal system" (Byrd & Castner, 2009, p. 519). Understanding how a body reacts to injuries both before and after death helps forensic scientists understand the nature of death and what injuries directly resulted in an individual's death.
Other biological sciences are also crucial for modern forensics. Entomology refers to the study of insects and can be used to assist criminal investigations. Forensic entomology focuses on interpreting insect-related data to determine characteristics involving time of death for murder victims. Essentially, arthropods are considered "indicators of critical forensic parameters," and "scientific analysis and the expert opinion of qualified forensic entomologists are now routinely solicited by law enforcement and legal professionals in both criminal and civil investigations" (Byrd & Castner, 2009, p. 127). The study of insect life span and reproductive cycles has helped determine time of death. Ultimately, "forensic entomology starts at the death scene or site of recovery. Many of the arthropods associated with the general fauna of decomposition are not on the remains, but distributed around the remains, or even inhabiting the soil under the remains" (Byrd & Castner, 2009, p. 128). By recognizing these features and evaluating the presence of particular species, a forensic scientist can provide a very accurate time period for time of death.
Computer forensics is one of the most recent developments that law enforcement uses to assist in criminal investigations. Obviously, "the ultimate objective of computer forensics is to collect and analyze computer evidence in a manner enabling its successful admission in court" (Casey, 2001, p. 69). Technicians use specially designed forensic programs to collect data as evidence from the memory systems of computers, tablets, and smartphones. Programs can also restore deleted evidence that may have been erased by a suspect to prevent being linked to a crime. Search engine content can also be important in establishing motive and showing signs of premeditation of crimes.
Overall, forensics is a huge part of criminal investigations today. It is a field that has evolved dramatically in just the last few decades and continues to change as innovative new technologies empower it to new heights. Understanding the crucial role between forensics and law enforcement strategies helps assist criminal investigations and come to more reliable conclusions.
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