What is a Crime Scene Investigator? The Crime Scene Investigator (CSI) collects and preserves a variety of evidence from an active crime scene. The crime scene investigator is most often a law enforcement professional responsible for the identification, collection, preservation, and cataloging of physical evidence at the crime scene. What Does a Crime Scene Investigator Do? Although many people assume that the crime scene investigator is responsible for the performance of tests of various types of physical evidence, forensic professionals (…)