The Locard Exchange Principle

The Locard Exchange Principle states that whenever two objects or people come into contact, there is always a transfer of materials or information between them. In forensic science, this means that a criminal leaving a crime scene will inevitably leave something behind, like fibers, fingerprints, or DNA, while also picking up evidence from the scene. This concept helps investigators link suspects to a crime or establish connections between people, objects, and locations, making it a foundational idea in solving crimes through physical evidence.