What principle underlies the theory of crime scene investigations?

The principle that everyone at a scene alters evidence is vital to understanding the dynamics of a crime scene investigation. This concept emphasizes the idea that any person who enters a crime scene, whether they are a witness, first responder, or investigator, can unintentionally disturb or alter evidence. This alteration can occur through physical contact, contamination, or even merely the act of moving around the scene.

Recognizing the potential for evidence alteration reinforces the importance of securing a crime scene promptly and limiting access to only those individuals necessary for the investigation. Investigators must be mindful of this principle to ensure that they preserve the integrity of the available evidence and accurately reconstruct the events that took place.

The other options do not encapsulate this foundational concept of evidence handling at a crime scene as directly. While all evidence may be observable and each scene indeed has unique characteristics, these aspects do not highlight the critical concern regarding the alteration of evidence by individuals present at the site. Additionally, the notion that people can hide their involvement pertains to human behavior but does not relate to the procedural foundations of crime scene management.