Many commercial establishments will hire a private investigator to prevent and investigate theft. Although this position does not always comprise the word "detective" or "investigator", private investigators have a team that helps perform research tasks. Many casinos and hotels hire private investigators to protect their clients. Private investigators help in the investigation of thefts or misconduct which occur on their client's premises. In some circumstances, investigators also serve as surveillance.
In addition, another common situation private investigators encounter is burglary or intrusion. In most countries, it is illegal to enter onto private properties without the authorization of the tenant or owner. Therefore, private investigators often conduct property surveillance in public areas to avoid legal problems.