The plaza of Memorial Amphitheater was altered once more in 1999. The unidentified remains of a Vietnam War servicemember were interred in the Vietnam War vault at the Tomb of the Unknowns on May 28, 1984. But questions were raised in 1994 that indicated the Army (under pressure from the Reagan administration to placate veterans' groups by finding a Vietnam War unknown) ignored evidence that the remains could be identified. After extensive media attention, the Vietnam War unknown was exhumed from the Tomb of the Unknowns on May 14, 1998. DNA testing revealed on June 30, 1998, that the remains were those of United States Air Force 1st Lieutenant Michael Blassie. On September 16, 1999, the marble slab over the now-empty burial vault was replaced by a new slab in a ceremony overseen by Secretary of Defense William Cohen. The new slab was inscribed with the words "Honoring and Keeping Faith with America's Missing Servicemen." Department of Defense officials decided to replace the old slab with a new one given how unlikely it was that unidentified Vietnam War remains would ever be found. Covering the vault to make it appear as if it did not exist was rejected.