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: Core Concept:
The question addresses a key concept in forensic science: the exchange of evidence between objects during contact. This exchange is vital for connecting a suspect to a crime scene or a victim.
Step 2: Option Analysis:
Let's examine the choices:

(A) Law of Circumstantial Facts: This legal principle involves inferring a fact from other established facts; it's unrelated to trace evidence.
(B) Locard's Principle of Exchange: Developed by Dr. Edmond Locard, this principle is foundational to trace evidence analysis. It states that all contact results in a mutual exchange of material. The question's statement directly describes this principle.
(C) Law of Comparison: This principle requires comparing an item or substance to a known standard sample for identification. For example, comparing fingerprints. It focuses on analysis, not the initial evidence transfer.
(D) Principle of Probability: This principle assesses the likelihood of evidence uniqueness or coincidence (e.g., a DNA match). It concerns the statistical significance of evidence, not its creation or transfer.
Step 3: Conclusion:
The statement "every contact leaves a trace" perfectly summarizes Locard's Principle of Exchange.