The Contamination of Evidence
Contamination refers to the addition of foreign materials or artifacts which may change or obscure the original nature of evidence. It can happen at all stages of an investigation, including the initial gathering of evidence from the scene of the crime and its subsequent analysis at the laboratory. It can be intentional or accidental and can cause serious problems for the reliability and integrity of evidence collected.
You cannot overstate the importance of not contaminating evidence. A crime scene evidence can often be used to investigate the incident, identify suspects and secure convictions. The evidence may have a contaminated value, meaning it can become difficult to ascertain its significance and cause misinformation. Contamination of evidence may also compromise the chain, making it more difficult to track the history, handle, and verify the authenticity of the evidence.