A World War II historian says the Marine Corps treated a veteran's family unfairly when it decided the former Marine wasn't in a famous World War II photograph of Marines raising the U.S. flag on Iwo Jima.

The Marines initially identified Sgt. Henry Hansen of Somerville, Mass., as one of six men in the Pulitzer Prize-winning photograph. But the corps changed its position two years later after another soldier's family complained. Both of the soldiers had died in the war.Professor Parker B. Albee, a professor at the University of Southern Maine, says his two years of independent research indicates the Marines' investigation was not thorough enough.

"I think (the Marine Corps) should pursue the investigation and reopen the case," Albee said. "It's been gnawing at the family for three generations."

But the Marine Corps said Friday that it doesn't see a need for another investigation.

The photograph was taken by Associated Press photographer Joe Rosenthal on Feb. 23, 1945, as the Marines raised the flag atop Mount Suribachi during one of the bloodiest battles in the Pacific.

Hansen was initially identified by one of the pictured survivors as the man standing at the far right in the photo.

Three of the six Marines, including Hansen, were later killed in combat as Japanese troops fought to maintain a hold on the strategic island.

Hansen's mother, Madeline Evelley, joined the three survivors later that year at a War Bond rally, where she was honored and given a copy of the photo.

Two years later, the Marine Corps said the man first thought to be Hansen was actually Cpl. Harlon H. Block of Weslaco, Texas, a Marine also killed in action.

Stunned by the change, Hansen's mother wrote to the Marine Corps commandant and to members of the Massachusetts congressional delegation, seeking an explanation.

The Marine Corp told her it had conducted a throrough investigation, but it never presented any evidence to back up its finding, Albee said.

Evelley died convinced that her son was among the six in the picture. Her four surviving children also thought the Marines' investigation was unfair and passed their doubts to a third generation.

Evelley's granddaughter, Judy Galgay of Naples, asked the professor to investigate.

"This was always told to us as children growing up that the man at the base of the flag was our Uncle Henry," she said Friday.

Albee said he combed through papers of the Hansen and Evelley families and other manuscripts and concluded the Marine Corps investigation was neither fair nor thorough.

One survivor, Rene Gagnon of Manchester, N.H., identified the other five Marines in the picture when he was ordered back to the United States in 1945. He said Hansen was among the five.

But a year later, Block's parents wrote to another survivor, Ira Hayes of Sacaton, Ariz., saying they had heard the Marine identified as Hansen was actually their son.

Hayes agreed, triggering a second examination of the photograph.

After reading an affidavit from Hayes, Gagnon and the third survivor - John Bradley of Antigo, Wis. - changed their stories and told a three-member board of officers that the man may have been Block.

Albee says Bradley and Gagnon may have been pressured into agreeing with Hayes. Gagnon has since died and Bradley doesn't talk to reporters.

Rosenthal, who lives in San Francisco, said the Marines who raised the flag dispersed after he shot the picture and he was not able to get their names.

Albee said he is not sure whether the man whose identity is in dispute was Hansen, Block or someone else.

"It could be one of them or it could be neither of them," Albee said.

He suggested that the matter be reopened and that investigators study other photographs taken about the same time by two still photographers and one with a movie camera.

"The one way to resolve it at this point in time is through a careful study of the pictures, which I am surprised they didn't do at the time," he said.

Robert Aquilina, assistant head of the reference section at the Marine Corps Historical Center in Washington, D.C., said the Marines made a mistake when it first said Hansen was in the photograph.

"I think they made a quick judgment that it was Hansen who was in the photo. Then, they found out later that it was Block. My understanding is that Block was identified by the survivors," Aquilina said.

But Albee says the Marines' evidence wasn't convincing.

"I have a feeling that they wanted a conclusion and felt under pressure to know who it was," he said. "I wish they said it was unknown, or had conducted the investigation thoroughly and fairly to a logical end."