Crime scene investigator trainees work under the supervision of professional investigators to learn how to collect and process evidence. As a CSI trainee, you travel to the crime scene with your team, observe how they determine what evidence to gather and learn the proper techniques for handling and documenting the evidence. Once they are back at the office, you train on how to record, process, and store evidence properly to ensure it is not tampered with or damaged. CSI trainees may work in a law enforcement laboratory or an office setting under the guidance of senior CSIs and other professionals.