Private detectives and investigators are responsible for collecting facts and evidence through surveillance, interviews and searches. They also provide businesses, attorneys and the public with various personal, financial and legal help.

The majority of detectives and investigators receive training in physical surveillance which involves watching a specific site from an unobtrusive location, usually inside a vehicle. They are trained to collect evidence through cell phones, computer database searches, binoculars, video and cameras. Investigators and detectives also obtain personal information such as prior arrests, telephone numbers, convictions and motor vehicle registrations through the use of computers.

Private detectives and investigators commonly work in areas of specialty. Such specializations include asset searches and intellectual property and court cases.

Corporate investigators are employed by various corporations to carry out external and internal investigations. External investigations are often held to protect a corporation from outside criminal activity including theft and counterfeiting. Internal investigations are conducted within the workplace to locate drug use, account violations and theft.