Tom Gray's family has waited for more than 70 years to bring home the remains of his cousin who was killed in the Japanese bombing of Pearl Harbor in 1941.

On Tuesday, they got a step closer when the military announced it would exhume and attempt to identify the remains of almost 400 sailors and Marines from the USS Oklahoma who were buried as unknowns after the war.

Gray's cousin, Edwin Hopkins, of Swanzey, New Hampshire, was a 19-year-old fireman third class on board the USS Oklahoma when the battleship was hit by nine torpedoes and capsized on Dec. 7, 1941. His remains weren't identified and his family was told he was missing.

Gray said Hopkins' mother never accepted that. She believed he had amnesia and he would show up one day, Gray said.

Hopkins' parents, Frank and Alice Hopkins, put his name on their headstone in Keene, New Hampshire, thinking he would join them one day, Gray said.

They did so, "just waiting for him to come home," Gray said.

All together, 429 sailors and Marines on board the Oklahoma were killed. Only 35 were identified in the years immediately after.

Hundreds were buried as unknowns at cemeteries in Hawaii. In 1950, they were reburied as unknowns at the National Memorial Cemetery of the Pacific inside a volcanic crater in Honolulu.

The military is acting now because advances in forensic science and technology as well as genealogical help from family members have made it possible to identify more remains, said Lt. Col. Melinda Morgan, a Defense POW/MIA Accounting Agency spokeswoman.

Officials plan to begin the work in three to six weeks, Morgan said. They aim to identify the remains of up to 388 servicemen within five years.

In 2003, the military disinterred one casket from the Honolulu cemetery, commonly called Punchbowl, based on information provided by Ray Emory, a Pearl Harbor survivor who has spent years doggedly scouring documents.

Many remains were co-mingled when buried, and the military was able to identify five servicemen from that casket. But the coffin also contained the remains of up to 100 others who haven't been identified.

Gray said his family in 2008 learned from a group of USS Oklahoma survivors that Emory had identified discrepancies in the records of the 22 buried as unknowns, including his cousin.

The 22 are buried in about five graves at Punchbowl, Gray said.

"Since then, the families have been fighting to have these sailors disinterred and brought home," said Gray, who lives in Guilford, Connecticut.

Gray said he understands it's an honor to be buried at a national cemetery. At the same time, he said Hopkins is part of his family.

"I also think that a boy gives up his life at 19 years old and ends up in a co-mingled grave marked as 'unknown' isn't proper. I never did," Gray said.

The unidentified remains of sailors and Marines from other Pearl Harbor battleships, like the USS West Virginia, are also buried at Punchbowl.

On Tuesday, the Pentagon announced new criteria for exhuming these and other remains from military cemeteries for identification.

In the case of co-mingled remains, the military must estimate it will be able to identify at least 60 percent of the people exhumed. For individual unknowns, there must be at least a 50 percent chance it will be able to identify the person disinterred.