Dozens of American military prisoners of war died in Tokyo amid the U.S. firebombing of Japan as World War II reached a crescendo in the Pacific, and later their commingled remains were buried in the Philippines.

Now, Pentagon researchers are working to identify those airmen, decades after their tragic end in the Japanese prison housing captured U.S. troops.

In Hawaii, the Defense POW/MIA Accounting Agency has launched the Tokyo Prison Fire Project, which is analyzing the burnt and mixed remains exhumed from the Philippines. Teams are working with a list of 62 service members killed at the prison compiled from reports of Japanese personnel and the memories of some U.S. POWs who were transferred to other prison camps before the fire.

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The difficult task of working with historical records and deteriorating remains is in the early stages — the outcome is still uncertain — but the project has opened a window into the past and shed light on the long-ago deaths of service members killed in the U.S. push for a Japanese surrender during the last world war.

On the night of March 9, 1945, the 62 U.S airmen held at the Tokyo Military Prison were among the survivors in what was by some estimates the single most devastating air raid ever conducted, surpassing in destructive power the later atomic bombings of Hiroshima and Nagasaki.

In what was called “Operation Meetinghouse,” more than 275 B-29 Superfortress bombers hit Tokyo with 1,667 tons of incendiaries — mostly 500-pound E46 cluster bombs, with each bomb containing 38 M69 bomblets filled with napalm that was in turn ignited by white phosphorus.

“The chosen areas were saturated. Fifteen square miles of Tokyo’s most densely populated area were burned to the ground” in the firestorm that incinerated the wood and paper houses of the city and killed an estimated 80,000 to 100,000 people, according to the 1946 U.S. Strategic Bombing Survey on the Pacific war ordered up by President Harry S. Truman.

The prison holding the 62 American POWs — all of them B-29 crew members who were captured when their planes were shot down — escaped damage, but Army Air Forces Maj. Gen. Curtis “Bombs Away” LeMay and the XXI Bomber Command were not done with Tokyo.

The March 1945 firebombing of Tokyo was the result of a major strategic shift in the use of the B-29s. Gen. Henry “Hap” Arnold, the Army Air Forces chief, was pressing for new tactics to replace the relative ineffectiveness of daytime, high-altitude precision raids against Japanese military targets.

LeMay ordered the switch to low-altitude nighttime raids against Japanese cities with incendiaries that guaranteed a high civilian death toll, but both LeMay and Arnold were convinced that it was the only course to take in possibly forcing a Japanese surrender that would avoid a ground invasion by the U.S. and the horrific casualties that would result.

In the 10 days after the March 1945 firebombing of Tokyo, the XXI Bomber Command dropped 9,373 tons of bombs on Tokyo, Nagoya, Osaka and Kobe, destroying a total of 31 square miles of those cities, according to the Strategic Bombing Survey. Referring to the mounting civilian death toll, LeMay remarked that, “If we lose, we’ll be tried as war criminals.”

Then on the night of May 23, 1945, more than 500 B-29s taking off from bases in the Marianas firebombed Tokyo again in a raid that consumed the Tokyo Military Prison, killing all 62 of the American POWs.

After the war, the American Graves Registration Service went to the prison site and disinterred the remains of the U.S. airmen who perished in the fire from a mass grave where they had been buried by the Japanese.

The service was able to identify some of the 22 officers and 40 enlisted personnel, and the remains of the rest were sent to the Philippines and buried as unknowns at the Manila American Cemetery and Memorial.

As part of the new effort to identify them, the unknowns were disinterred from the Manila cemetery in 2022 and transferred to the DPAA labs at Joint Base Pearl Harbor-Hickam, Hawaii, where teams of technicians led by forensic anthropologists Dr. Aelwen Wetherby and Kristen Grow have cautioned against expectations of seeing identifications made quickly.

In email responses to questions from Military.com, Wetherby and Grow said they were working with a total of 39 sets of remains from the Tokyo Prison fire but could give no estimate at this point on when or if any of the remains might be identified.

In addition, “it is not possible to say at this point how many individuals are represented” in the 39 sets of remains, “as we are still in the preliminary stages of our investigations and awaiting results from all our scientific analyses,” Wetherby and Grow said.

“The remains recovered from the Tokyo Military Prison pose considerable forensic challenges due to their extreme commingling, with multiple individuals often present in a single casket,” and the damage from fire only added to the difficulty of making identifications, Wetherby and Grow said.

However, the DPAA has received family reference samples of DNA for more than 70% of the unresolved cases of those who died in the Tokyo Military Prison fire, which could be critical in eventually making identifications, Wetherby and Grow said.

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