On Dec. 7, 1941, Clifford was assigned to the battleship USS Oklahoma, which was moored at Ford Island, Pearl Harbor, when the ship was attacked by Japanese aircraft. The USS Oklahoma sustained multiple torpedo hits, which caused it to quickly capsize. The attack on the ship resulted in the deaths of 429 crewmen, including Clifford.
From December 1941 to June 1944, Navy personnel recovered the remains of the deceased crew, which were subsequently interred in the Halawa and Nu’uanu Cemeteries.
In September 1947, tasked with recovering and identifying fallen U.S. personnel in the Pacific Theater, members of the American Graves Registration Service (AGRS) disinterred the remains of U.S. casualties from the two cemeteries and transferred them to the Central Identification Laboratory at Schofield Barracks. The laboratory staff was only able to confirm the identifications of 35 men from the USS Oklahoma at that time. The AGRS subsequently buried the unidentified remains in 46 plots at the National Memorial Cemetery of the Pacific (NMCP), known as the Punchbowl, in Honolulu. In October 1949, a military board classified those who could not be identified as non-recoverable, including Clifford.
Between June and November 2015, DPAA personnel exhumed the USS Oklahoma Unknowns from the Punchbowl for analysis.
To identify Clifford’s remains, scientists from DPAA used dental and anthropological analysis. Additionally, scientists from the Armed Forces Medical Examiner System used mitochondrial DNA (mtDNA) and Y chromosome DNA (Y-STR) analysis.
Clifford’s name is recorded on the Courts of the Missing at the Punchbowl, along with the others who are missing from WWII. A rosette will be placed next to his name to indicate he has been accounted for.
Clifford will be buried May 2, 2023, in Douglas, Kansas.