An entry-level crime scene investigator (CSI) identifies and collects evidence at a crime scene. In this role, your job is to document everything in the area of suspected criminal activity by taking pictures, recording measurements, and gathering information that may not be captured by images, such as weather conditions. As an entry-level employee, you undergo on-the-job training and work under the supervision of senior crime scene staff members and investigators. You may shadow veteran investigators for a while, observing how they extract and process evidence at the crime scene and back at the office; it is crucial to preserve evidence properly to ensure it does not become tainted.