Definition
- Lockard’s Exchange Principle states that whenever two objects come into contact, there is a transfer of material from one to the other.
- This principle forms the basis for understanding how evidence is exchanged during criminal activities.
Material Transfer
- From Scene to Person:
- Traces from crime scenes (such as fibers, hair, or blood) can be carried away on the clothes or tools of a criminal.
- From Person to Scene:
- Simultaneously, traces from the criminal (such as fingerprints or skin cells) may be left at the scene.
- These silent pieces of evidence serve as crucial clues.
Examples of Traces
- Fingerprints: Left on surfaces touched by the criminal.
- Hair and Fibers: Shed unintentionally and left behind.
- Broken Glass or Paints: Evidence of forceful entry or exit.
- Blood or Seminal Stains: Indications of violent acts.
Significance and Proof
- Actual Evidence: Lockard’s principle provides actual evidence of a crime.
- Absolute Proof: The presence of physical evidence is irrefutable.
- Absence of Evidence: If no traces are found, it doesn’t mean the crime didn’t occur; it simply means no exchange occurred.