Which of the following measures helps prevent contamination at a crime scene?

• A. Wearing personal protective equipment
• B. Limiting access
• C. Documenting transfers
• D. All of the above

Answer: (D)

Preventing contamination at a crime scene comes down to controlling who and what interacts with the evidence and scene. Wearing personal protective equipment creates a barrier between investigators and the scene, so your own hair, fibers, skin oils, or other residues don’t get transferred to evidence. It also protects you from potential hazards. Proper PPE is used consistently and changed if it becomes compromised, which helps keep the scene clean.

Limiting access is another crucial step. Keeping the crime scene restricted to essential personnel reduces the number of people who could introduce foreign materials or disrupt the arrangement of evidence. A well-defined perimeter and a documented entry log help preserve the scene’s integrity.

Documenting transfers is essential for maintaining the chain of custody. Recording every time evidence is touched or moved, and by whom and when, ensures there is a clear history of handling. This prevents confusion about who may have introduced contamination and allows later analysts to trace the evidence’s journey accurately.

All of these measures work together to minimize contamination and preserve evidence integrity, which is why choosing all of the above is the best answer.