Many private investigators decide to specialize in one type of investigation. The reason for this is because some cases involve so much knowledge in a required area that trying to concentrate on more than just that area of expertise becomes very difficult. Just like many doctors concentrate on one type of medicine, such as ear, nose and throat, or gynaecology, many detectives also specialize.

Legal investigators specialize in cases that usually end up going to trial such as murder investigations. They'll often assist in the preparation of legal defenses, locating witnesses, serving legal documents, interviewing police and possible witnesses, and also assist in gathering and reviewing evidence. Legal investigators also sometimes collect information concerning the parties involved in the litigation and may even testify in court.

Corporate investigators perform the function of conducting internal and external investigations for large corporations. In the case of an internal investigation they may investigate drug use by an employee or even corporate theft by an employee or group of employees. Much of the Enron scandal evidence was acquired by private investigators. When conducting an external investigation for a corporation a detective may be involved in uncovering criminal schemes to try to steal the company's private information on a new product.

Financial investigators are usually hired to investigate another company that the corporation may be thinking about doing business with for a possible merger. These investigations are intended to uncover any shady dealings that the prospective company may have been involved with. Many of these investigators are also certified public accountants as this skill is needed to be able to perform this job adequately.

Detectives who work for retail stores, hotels and other public places where theft is always possible, are mostly responsible for controlling losses, stopping theft and protecting assets. These store detectives are also known as loss prevention agents. They perform their job by apprehending anyone who is attempting to steal merchandise or destroy store property. They stop theft by shoplifters, vendor representatives, delivery personnel and even store employees. These detectives also perform periodic searches of stock areas, dressing rooms and rest rooms and will sometimes even assist in opening and closing the store itself. Part of their job requires them to fill out loss prevention and security forms and reports for the store owner and managers and also to testify in court against any persons that they themselves have apprehended in the act of a crime. In the case of hotel detectives they protect the hotel guests and their belongings against theft and also police the hotel bars and restaurants to prevent undesirables from causing trouble. Because of some of these duties, many of these investigators may have at one time been trained law enforcement officers, as the job can often get very ugly.

In our next article in this series we'll continue with the working conditions of private investigators.