Which procedure best prevents contamination of evidence at a crime scene?

• A. Move evidence to lab before documenting.
• B. Immediately publish all details in a public report.
• C. Reopen the scene to public access.
• D. Secure the scene, limit access, document handling, use proper packaging, and maintain chain of custody.

Answer: (D)

Preventing contamination at a crime scene hinges on securing the area, limiting who can access it, documenting every action taken with evidence, using proper packaging, and maintaining a clear chain of custody. Securing the scene and restricting access minimizes who touches items and reduces the chance of altering or moving evidence. Thorough documentation of each step—who collected what, when, and where it was stored—creates a reliable record that prevents loss or misinterpretation of context. Proper packaging protects items from cross-contamination and damage during handling and transport. Keeping an unbroken chain of custody provides a traceable history of every person who handled the evidence, when, and under what conditions, which is crucial for admissibility in court.

Moving evidence to a lab before documenting disrupts this controlled process and can lead to lost or misidentified items and a broken chain of custody. Publishing all details publicly and reopening the scene to public access would introduce unnecessary exposure, increasing the risk of contamination, tampering, or inadvertent alteration.