Modern society has in recent times relied almost exclusively on the police and other arms of the criminal justice system to prevent and control crime. But today the sheer volume of crime and its cost, along with budget cutbacks in the public sector, have overstrained public law enforcement agencies. One of the primary functions of private security personnel is investigation. Private investigation may be defined as the occupational activity performed by a private investigator who spends the majority of his or her time occupied with seeking information for a client who pays for such services. This study analyzed the private investigator system in the U. S. Allan Pinkerton started the first contract private security in the U. S. Pinkerton's early success helped define the role and abilities of the private security industry. Private investigators are individuals knowledgable in the methods and techniques of investigations, and they sell that expertise. In many cases, the client purchases the investigator's expertise and resources to acquire the desired information. Private investigators find facts and analyze information about legal, financial, and personal matters. All investigations, regardless of type or purpose, depend on the gathering of factual information. Gathering factual information is the main purpose fo any investigation. They offer many services, including verifying people's backgrounds, tracing missing persons, investigating computer crimes, and protecting celebrities. In general, private investigators are involved in locating missing persons, obtaining confidential information. and solving crimes. Many PIs work for businesses and lawyers while others work independently. Independent offices may be only one person operations while others may employ several operatives or contract work to part-time investigators. Private investigators may perform pre-employment background checks or look into a charge that someone has been stealing money from a company. They might be hired to prove or disprove infidelity in a divorce case. Private investigation combines the skills of both science and art. Private investigators must be mindful of the law when conducting investigations. They must have a good understanding of federal, state, and local laws, such as privacy laws, and other legal issues affecting their work. Investigators generally work alone, but they may work with others while conducting surveillance or following a subject. Many investigators enter the field after serving in law enforcement, the military, or federal intelligence jobs. These people, who frequently are able to retire after 25 years of service, often become private detectives or investigators as a second career. So, they must be knowledgeable of many things from good public relations to proper protocal, security principles and procedures, medical response, and how to aggressively control access to a crime/incident scene. Private investigators usually have some college education. However, many jobs do not have formal education requirements and private detectives and investigators learn on the job. Previous experience in investigative work can be beneficial. But education and training, coupled with common sense and good attitude, should be requisites for the position of private investigators. In most states, private investigators need a license. In Florida, for instance, there is double requirement - the applicant must be sponsored by a private investigator who works for a private investigative agency. The employment of private investigator is expected to grow much faster than the average for all occupations through the year 2014. The future of security is positive. Demand for investigators is expected to be generated by fear of crime, increased litigation, and the need to protect confidential information and property.