A field investigator performs surveillance and investigation tasks on behalf of institutions such as law enforcement agencies, law firms, insurance companies, or private individuals. As a field investigator, your duties may include locating subjects, surveilling individuals, conducting background checks and online research, interviewing witnesses, and inspecting documents. In some industries, you may work at a crime scene where your responsibilities include recording statements and gathering evidence. When you complete your investigations, you write detailed reports while complying with all state and federal privacy regulations.