Joseph Carroll (DIA)
When the U.S. Air Force was established as a separate executive department under the National Security Act of 1947, Secretary of the Air Force W. Stuart Symington, requested FBI Director J. Edgar Hoover to loan General Carroll to the services to organize a U.S. Air Force agency for investigative and counterintelligence functions. He organized and directed this new organization, the AFOSI, along the lines of the FBI rather than the U.S. Army's Criminal Investigation Command (USACIDC or CID). General Carroll was tendered a commission as a colonel, U.S. Air Force Reserve, January 12, 1948. He was ordered to active duty in the grade of brigadier general May 6, 1948, and promoted to major general August 11, 1950.
United States Department of the Army
The "Department of War" was originally formed in 1789 as an Executive Department of the United States, and was split by the National Security Act of 1947 into the Department of the Army and Department of the Air Force on September 18, 1947. By amendments to the National Security Act of 1947 in 1949, the Department of the Army was transformed to its present-day status.