The investigator sits in a car or other inconspicuous location. Some investigations involve verification of facts, such as an individual's place of employment or income. This might involve a phone call or a visit to the workplace. In other investigations, especially in missing persons cases, the investigator interviews people to learn as much as possible about someone's previous movements. These interviews can be formal or informal and sometimes turn into confrontations if the person is uncooperative.
Legal investigators specialize in cases involving the courts and lawyers.
To assist in preparing criminal defenses, investigators locate witnesses, interview police, gather and review evidence, take photographs, and testify in court. To assist attorneys in the preparation of litigation for injured parties, they interview prospective witnesses, collect information on the parties to the litigation, and search out testimonial, documentary, or physical evidence. Corporate investigators work for companies other than investigative firms-often large corporations. In contrast to most private investigators, they report to a corporate chain of command. They conduct internal or external investigations.