NACA Animal Control Officers Practice Test

What does the Locard Exchange Principle state?

1. All evidence must be preserved indefinitely

2. Any interaction with a crime scene alters it

3. Victims must be interviewed before evidence is collected

4. Physical evidence is always the most important

The correct answer is: Any interaction with a crime scene alters it

The Locard Exchange Principle is a foundational concept in forensic science that asserts whenever an individual makes contact with an environment, a transfer of material occurs. This means that any interaction with a crime scene will inevitably alter it, whether it's through leaving behind trace evidence like hair or fibers or taking something away, such as fingerprints. This principle underscores the importance of careful handling and documenting all interactions at a crime scene, as each action can compromise the integrity of the evidence collected. By emphasizing the inevitable alterations caused by human interaction, this principle becomes crucial for those in animal control and law enforcement fields when investigating crime scenes. Understanding that evidence can be affected by the presence of individuals reinforces the need for meticulous procedures and approaches to preserve the scene as much as possible.