In terms of evidence preservation, what should be avoided at all costs?

In the context of evidence preservation, it is crucial to avoid touching anything unnecessarily at a crime scene. The integrity of physical evidence can be compromised by contamination, alteration, or destruction if items are handled improperly or without need. Touching evidence can leave behind fingerprints, DNA, or other residues that could interfere with forensic analysis or lead to questions about the authenticity of the evidence collected. This principle is fundamental in crime scene investigation because it helps maintain a clear chain of custody and supports the reliability of the evidence when it is ultimately presented in court.

Other activities, like photographing evidence, recording witness statements, and using established access routes, serve to document and preserve the scene's context rather than putting the integrity of physical evidence at risk. Therefore, avoiding unnecessary contact with evidence is a critical part of upholding the standards of forensic integrity.