In 1973 Congress passed Public Law 93-43 directing the Secretary of Defense to intern an unknown American serviceman from the Vietnam Conflict at The Tomb of the Unknowns. The sophisticated identification techniques were remarkably efficient, and it was not until 1984 that remains of an American serviceman were classified as unidentifiable. During ceremonies at Pearl Harbor on May 17, 1984, Sgt. Maj. Allan Kellogg, Jr., A Medal of Honor recipient during the Vietnam Conflict, placed a wreath before the casket, formally designating the Unknown from the Vietnam Conflict. The Unknown was placed aboard the USS Brewton for transport to the mainland United States. The Unknown arrived at the U.S. Capitol on May 25, 1984, where he lay in state for three days in the Rotunda. On Memorial Day, May 28, 1984, an elaborate funeral procession transferred the body to the Memorial Amphitheater. During the service, President Ronald Reagan presented the Medal of Honor to the Unknown. The Vietnam Unknown was then borne to the plaza and following religious rites, a 21 Gun Salute was rendered. The solemn service concluded with three volleys of rifle fire, followed by the sounding of Taps. The remains of the Vietnam Unknown were exhumed May 14, 1998. Based on mitochondrial DNA testing, Department of Defense scientists identified the remains as those of Air Force 1st Lt. Michael Joseph Blassie, who was shot down near An Loc, Vietnam, in 1972. Lieutenant Blassie was subsequently reinterred near his family's home in St. Louis, Missouri. Based upon the advancements in remains identification it seems unlikely that body of a truly unknown soldier from the Vietnam war could ever be found, and it has been determined that the crypt will therefore remain empty.

In 1973 Congress passed Public Law 93-43 directing the Secretary of Defense to intern an unknown American serviceman from the Vietnam Conflict at The Tomb of the Unknowns. The sophisticated identification techniques were remarkably efficient, and it was not until 1984 that remains of an American serviceman were classified as unidentifiable. During ceremonies at Pearl Harbor on May 17, 1984, Sgt. Maj. Allan Kellogg, Jr., A Medal of Honor recipient during the Vietnam Conflict, placed a wreath before the casket, formally designating the Unknown from the Vietnam Conflict. The Unknown was placed aboard the USS Brewton for transport to the mainland United States. The Unknown arrived at the U.S. Capitol on May 25, 1984, where he lay in state for three days in the Rotunda. On Memorial Day, May 28, 1984, an elaborate funeral procession transferred the body to the Memorial Amphitheater. During the service, President Ronald Reagan presented the Medal of Honor to the Unknown. The Vietnam Unknown was then borne to the plaza and following religious rites, a 21 Gun Salute was rendered. The solemn service concluded with three volleys of rifle fire, followed by the sounding of Taps. The remains of the Vietnam Unknown were exhumed May 14, 1998. Based on mitochondrial DNA testing, Department of Defense scientists identified the remains as those of Air Force 1st Lt. Michael Joseph Blassie, who was shot down near An Loc, Vietnam, in 1972. Lieutenant Blassie was subsequently reinterred near his family's home in St. Louis, Missouri. Based upon the advancements in remains identification it seems unlikely that body of a truly unknown soldier from the Vietnam war could ever be found, and it has been determined that the crypt will therefore remain empty.