Background — Baron 52
On the night of 4–5 February 1973, five days after the Paris Peace Accords were signed, a U.S. Air Force EC-47Q electronic intelligence aircraft, call sign Baron 52 (tail number 43-48636), was shot down over Saravane Province, southern Laos, while conducting a signals-intelligence mission along the Ho Chi Minh Trail. 
The eight-man crew consisted of four flight-deck personnel from the 361st Tactical Electronic Warfare Squadron and four back-end electronic warfare specialists from Detachment 3, 6994th Security Squadron:
SSgt. Todd M. Melton, Sgt. Joseph A. Matejov, Sgt. Peter R. Cressman, and Sgt. Dale Brandenburg — the “Four Pirates.” 
No identifiable remains of the four back-end specialists were found in the wreckage. Within hours of the loss, NSA intercepts (REFNO 1983) reported that Group 210 was holding four “pirates” (a standard cover term for American pilots) and moving them from kilometer marker 44 to 93 under an individual referred to as “Mr. Van,” with difficulties along the road. A related intercept referred to four pilots being held captive. 
Despite this, the Air Force quickly determined that all eight men were killed in the crash. In the mid-1990s the case was officially closed as accounted for, with a group burial at Arlington. The families of the four back-end crew members, along with independent researchers, have continued to argue that the SIGINT, crash-site evidence, and later Vietnamese unit accounts indicate the four men survived, were captured, and were moved through the Trail logistics network. 
This song is part of that ongoing effort to raise awareness.
Full research, documents, and updates:
StoriesOfSacrifice.org