The difference Crime Scene and Crime Lab

Role of a Crime Scene Investigator: Collection vs. Testing

Crime Scene Investigators (CSIs) primarily collect and preserve evidence, but they may perform some preliminary, or "presumptive," tests in the field.

CSIs do not typically conduct the in-depth, definitive testing that occurs in a crime lab. Their main responsibility is to document the scene and collect evidence in a way that prevents contamination and preserves its integrity. They carefully bag, tag, and log each item before it is transported to the lab for a forensic scientist to perform the detailed analysis.

However, CSIs may use simple field tests to quickly identify potential evidence. For example, they might use a chemical spray to test a stain for the presence of blood, which helps them decide what to collect. This is a preliminary test, and the stain would still be sent to the crime lab for a definitive DNA test and further analysis.

Sample Answer

A crime scene is any location where a crime has occurred or where evidence related to a crime may be found, while a crime lab is a scientific facility where forensic scientists analyze physical evidence. The two serve distinct but interconnected roles in an investigation.

The Difference: Crime Scene vs. Crime Lab

Crime Scene: This is the physical location of the crime. The work here is done by Crime Scene Investigators (CSIs), whose primary job is to secure the area, document the scene through photographs and sketches, and meticulously search for, collect, and preserve physical evidence. Their work is field-based and focuses on maintaining the integrity and chain of custody of the evidence from the moment it is found.

Crime Lab: This is a controlled laboratory environment where forensic scientists use specialized scientific methods to analyze the evidence collected from the crime scene. Their work is lab-based and involves detailed analysis, such as DNA profiling, fingerprint analysis, ballistics, toxicology, and trace evidence analysis. Forensic scientists provide the detailed scientific findings that can link a suspect to a crime or a victim.