Legal Definitions - Defense Investigative Service

The Defense Investigative Service (DIS) was a United States federal agency that operated from 1972 until 1999. Its primary mission was to conduct background investigations for individuals seeking or holding security clearances within the Department of Defense (DoD) and other federal agencies. These investigations were crucial for determining an individual's eligibility to access classified national security information, assessing factors such as loyalty, character, and trustworthiness. In 1999, the functions of the DIS were transferred to the newly established Defense Security Service (DSS), which has since been reorganized into the Defense Counterintelligence and Security Agency (DCSA).

Here are some examples illustrating the role of the Defense Investigative Service:

• Imagine a software engineer in the late 1980s working for a private company that won a contract to develop secure communication systems for the U.S. Army. To access the classified information necessary for this project, the engineer required a "Secret" security clearance. The Defense Investigative Service would have been responsible for conducting the extensive background investigation, which included interviewing neighbors, verifying educational and employment history, and checking for any potential security risks, before the clearance could be granted.

• Consider a young Air Force captain in the early 1990s who was selected for a highly sensitive intelligence role. This position demanded a "Top Secret" security clearance, the highest level. The Defense Investigative Service would have initiated a thorough investigation into the captain's life, examining their financial records, foreign contacts, personal conduct, and any other factors relevant to national security, to ensure they met the strict criteria for handling such sensitive information.

• A civilian employee at a naval shipyard, who had held a "Confidential" security clearance since the late 1970s, would have undergone periodic reinvestigations to maintain their access to classified materials. In the mid-1990s, the Defense Investigative Service would have conducted one of these reinvestigations, reviewing updated personal information and ensuring the employee continued to meet all security standards required for their position.