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In 1921, President Harding presided over a re-burial of an unknown American serviceman who died in WWI. Since then, the Tomb of the Unknown Soldier has hosted an unidentified serviceman from WWII, Korea and Vietnam.
However, in 1998, scientists exhumed the remains of the unknown Vietnam War soldier and applied state-of-the-art mitochondrial DNA testing. They revealed the unknown soldier to be Air Force 1st Lieutenant Michael Joseph Blassie, who was shot down near An Loc, Vietnam, in 1972.
Following his identification, Blassie’s family moved him to Jefferson Barracks National Cemetery, and the tomb remains vacant today.