Question

According to which principle or law of Forensic science, it is asserted that, "when a criminal or his/her instrument of crime comes in contact with the victim or the objects surrounding him/her, they leave traces, and the criminal or his/her instrument picks up traces from the same contact?"

• A. Law of Circumstantial Facts
• B. Locard's Principle of Exchange
• C. Law of Comparison
• D. Principle of Probability

Hint:

The simple phrase to remember this fundamental forensic principle is: "Every contact leaves a trace." This is the core of Locard's Exchange Principle and the basis for collecting trace evidence like hair, fibers, and soil from a crime scene.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The question describes a fundamental concept in forensic science related to the transfer of evidence between objects upon contact. This is crucial for linking a suspect to a crime scene or a victim.
Step 2: Detailed Explanation:
Let's analyze the given options:

(A) Law of Circumstantial Facts: This is a legal principle related to evidence where a fact is inferred from other proven facts, rather than a specific forensic principle about trace evidence.
(B) Locard's Principle of Exchange: Formulated by Dr. Edmond Locard, a pioneer in forensic science, this principle is the cornerstone of trace evidence analysis. It states that with every contact between two objects, there will be a mutual exchange of matter between them. The quote in the question is a direct explanation of this principle.
(C) Law of Comparison: This forensic principle states that for an object or substance to be identified, it must be compared to a known standard sample. For example, comparing a suspect's fingerprint with one found at the scene. It's about analysis, not the initial transfer of evidence.
(D) Principle of Probability: This principle is used to determine the likelihood that a specific piece of evidence (like a DNA match) is unique or coincidental. It's about the statistical significance of evidence, not its creation or transfer.
Step 3: Final Answer:
The assertion that "every contact leaves a trace" is the essence of Locard's Principle of Exchange.