Security guards, who are also called security officers, patrol and inspect property to protect against fire, theft, vandalism, terrorism, and illegal activity. These workers protect their employer’s investment, enforce laws on the property, and deter criminal activity or other problems. Security guards use radio and telephone communications to call for assistance from police, fire, or emergency medical services as the situation dictates. Security guards write comprehensive reports outlining their observations and activities during their assigned shift. They may also interview witnesses or victims, prepare case reports, and testify in court.

Although all security guards perform many of the same duties, specific duties vary based on whether the guard works in a “static” security position or on a mobile patrol. Guards assigned to static security positions usually serve the client at one location for a specific length of time. These security guards must become closely acquainted with the property and people associated with it and often monitor alarms and closed-circuit TV cameras. In contrast, security guards assigned to mobile patrol duty drive or walk from location to location and conduct security checks within an assigned geographical zone. They may also detain or arrest criminal violators.