Locard's Exchange Principle

Locard's Exchange Principle states that whenever a person comes into contact with another person or an object, they will leave behind traces of their presence and take traces away with them. This means that physical evidence—such as hair, fingerprints, or fibers—can be transferred between individuals or between individuals and the environment. In forensic science, this principle is crucial for solving crimes, as it helps investigators link suspects to crime scenes through the evidence they leave behind, supporting the idea that "every contact leaves a trace."