U.S. Defense Intelligence Agency

The DefenseIntelligence Agency (DIA) is a United States federal agency that serves as the country's main foreign military espionage organization under the jurisdiction of Department of Defense. As one of the principal member of the U.S. Intelligence Community (IC), DIA informs national civilian and defense policymakers about the military intentions and capabilities of foreign governments and non-state actors, while also providing department-level intelligence assistance and coordination to individual military service intelligence components and the warfighter. The agency's role encompasses collection and analysis of defense-related foreign political, economic, industrial, geographic, and medical and health intelligence. As part of its national IC responsibilities, DIA regularly provides input for the President's Daily Brief. Although the DIA is designated a Department of Defense combat support agency, two-thirds of its 17,000 employees are civilian and its intelligence operations in support of U.S. national security extend far beyond the zones of combat - at hundreds of locations in approximately 140 countries. The agency primarily specializes in collection and analysis of human-source intelligence (HUMINT), has its own Clandestine Service and is in charge of American military-diplomatic efforts overseas. DIA is also designated a national manager for the highly technical measurement and signature intelligence (MASINT). The agency has no law enforcement authority, although it is occasionally portrayed so in American popular culture.

Established in 1961 under President John F. Kennedy by Defense Secretary Robert McNamara, the DIA has been at the forefront of U.S. intelligence efforts throughout the Cold War and rapidly expanded, both in size and scope, since the September 11 attacks. 

The above information provided in part by Wikipedia, The Institute of Heraldry, Global Security, and the official websites of the corresponding units and formations.