Governing Principles and Laws of Forensic Science

 Governing Principles and Laws of Forensic Science

Introduction

 Forensic Science is a crucial field that plays a significant role in the pursuit of justice and the resolution of criminal investigations. In order to ensure the reliability and accuracy of its findings, Forensic Science operates on a set of guiding principles and laws. These fundamental principles form the backbone of forensic investigations and help establish the validity of evidence presented in courts of law. In this article, we will explore the seven basic principles that underpin the practice of Forensic Science.

 Principles of Forensic Science

 There are 7 basic principles in Forensic Sciences.

1.    Law of Comparison.
2.    Law of Individuality.
3.    Law of Analysis.
4.    Law of Probability.
5.    Law of Progressive Change.
6.    Principle of Exchange.
7.    Law of Circumstantial Facts.     

  1. Law of Comparison  

   The Law of Comparison is “Compare like with like”, it states that investigators must have known samples, often referred to as control samples, to compare with the evidence collected at a crime scene. By analyzing both the known and unknown samples, forensic experts can determine whether the evidence is consistent with the suspect, victim, or crime scene. No purpose will be served if a comparison is made between Grey Hair with Grey Fiber,   Nylon Fiber with Cotton Fiber,0.38 Bullet with 0.32 Bullet, and Telugu Writings with English writings.   

2. Law of Individuality 

  Every object, whether natural, manmade, or animate, possesses its own individuality and uniqueness, which is not replicated in any other object. Natural objects include a wide range of entities such as human beings, animals, plants, leaves, seeds, insects, wood, soil, and more.  Manmade objects, on the other hand, consist of items like tools, guns, bullets, shoes, pens, paper, ink, pills, and various other manufactured goods. The Law of Individuality holds immense significance in the field of forensic science. It allows forensic experts to differentiate and identify specific individuals or objects based on their distinct characteristics. Through the examination of acquired characteristics, forensic scientists can sometimes establish the connection between a person or an object and specific evidence found at a crime scene. This principle serves as the foundation of forensic investigations, enabling experts to draw crucial conclusions and provide valuable insights into complex cases.  

 3. Law of Analysis

   The Law of Analysis is a fundamental principle in forensic science, highlighting the critical importance of correct sampling and packaging for the effective utilization of expert analysis. Thus, the proper collection of samples and ensuring their integrity and chain of custody is of utmost significance. It is essential to recognize that drawing conclusions or interpretations without conducting a thorough analysis of the samples can lead to unreliable results. In other words, the quality and validity of the conclusion are directly dependent on the quality of the sample analyzed.

  4. Law of Probability

   Probability is a fundamental concept in forensic science, representing the frequency of occurrence of an event. It is particularly straightforward to determine the probability when flipping a coin since there are only two possible outcomes, heads or tails, each with an equal chance of happening. However, in some cases, establishing the exact probability becomes highly challenging. For example, when transferring dog hair or blue jeans fibers, it is nearly impossible to precisely define the probability of occurrence. The likelihood of asserting a common origin for these specimens is not always feasible in all cases. 

      In forensic analysis, all identifications, whether definite or indefinite, are made based on the law of probability, whether consciously or unconsciously. Forensic experts rely on statistical data and likelihood ratios to assess the probability of a connection between evidence and a suspect or crime scene, aiding in the process of reaching accurate conclusions.     

 5. Law of Progressive Change

   The Law of Progressive Change states that everything in the          Universe undergoes changes as time progresses. This principle holds significant importance in forensic science, particularly when dealing with criminal investigations, crime scenes, and related objects, as they can all undergo transformations that may render them unrecognizable. For example, let's consider a scenario where a crime is committed outdoors, and evidence such as footprints or tire tracks are left at the scene. Over time, weather conditions like rain or wind can erode or distort these impressions, making it challenging for forensic experts to accurately analyze and interpret the evidence. Similarly, in cases involving the decomposition of human remains, the postmortem changes that occur with time can significantly alter the condition of the body, making identification and cause of death determination more complex. 

     6. Principle of Exchange

   The Principle of Exchange, proposed by French scientist Prof. Edmond Locard in 1928, marked a pivotal moment in the systematic development of forensic science. According to this principle, whenever two objects come into contact with each other, there will always be an exchange of materials between them. For instance, when a criminal or a crime weapon comes into contact with the victim or the objects in the vicinity, they leave behind traces of physical evidence. Similarly, the criminal or the crime weapon can also pick up traces from this contact. As a result, it becomes the responsibility of the investigating officer to diligently search for, locate, and collect these crucial pieces of physical evidence. By doing so, they can establish links between the crime scene, the perpetrator, and potential witnesses, aiding in the reconstruction of events and providing valuable insights into the criminal act.

   7. Law of Circumstantial Facts

     The Law of Circumstantial Facts permits the use of indirect evidence and reasoning to draw conclusions in forensic investigations. Forensic scientists skillfully combine various pieces of circumstantial evidence to construct a comprehensive picture of the events surrounding a case. For example, consider a burglary case where the suspect's fingerprints are not found at the crime scene. However, investigators discover a tool at the scene that matches the unique marks left on the door. Additionally, surveillance footage shows a person resembling the suspect in the vicinity on the night of the crime. Individually, these pieces of evidence may not definitively point to the suspect's guilt. Still, when considered together, they create a strong circumstantial case against the individual. The Law of Circumstantial Facts plays a crucial role in forensic investigations where direct evidence may be limited or absent. By skillfully analysing and connecting multiple circumstantial clues, forensic experts can provide valuable insights and logical conclusions, aiding the justice system in making well-founded decisions.

 

Conclusion: 

    In conclusion, the seven forensic laws and principles discussed above form the bedrock of modern forensic science and play a fundamental role in the pursuit of truth and justice within the criminal justice system. These guiding principles provide a systematic framework for forensic experts to conduct thorough and unbiased investigations, ensuring the integrity and reliability of their findings.