It’s a case of mistaken identity for a celebrated second world war photograph: six troops raise an American flag in Iwo Jima, Japan. The photo has been printed in history books, displayed in museums and even won a Pulitzer prize. But for over 70 years, one of the figures appears to have been misidentified.

Three historians established that for seven decades, Cpl Harold “Pie” Keller has wrongly been identified as Pfc Rene Gagnon in the 23 February 1945 photo.

The historians Stephen Foley, Dustin Spence and Brent Westemeyer used archival film footage and other photos taken at Iwo Jima to establish the Keller’s identity. Their reveal comes only three years after historians discovered another marine in the photo was misidentified.

Keller’s identity was confirmed by a marines investigative board and investigators from the FBI’s digital evidence laboratory.

In a statement on Wednesday, the marines said: “Regardless of who was in the photograph, each and every Marine who set foot on Iwo Jima, or supported the effort from the sea and air around the island is, and always will be, a part of our Corps’ cherished history. In the words of General David H Berger, Commandant of the Marine Corps, ‘they are all heroes’.”

The family of Keller, who died of a heart attack in 1979, is grateful for the correction.

“Now we know he’s in that photo, too,” Keller’s daughter told NBC News. “When I would ask him about the photo on our wall, he would say something like, ‘That group raised a flag.’ He just never spoke much about this when we were growing up.”

The facts around the Pulitzer prize-winning photo have continually been rewritten. In 1946, the marines conducted an inquiry into the identities of the troops after a slew of claims of mistaken identities came pouring in.