A security guard is meant to be visible, and provide a sense of security to those around him. Guards are trained to address dangerous situations, and have full knowledge of first aid and CPR. A Security Guard is trained to observe and report and enforce private property rules. Private investigators on the other hand, are typically employed to investigate the actions or whereabouts of individuals. They can follow individuals and gather information at the direction of their client. Unlike security guards, investigators do not provide private property protection.