Nearly 75 years ago, Giichi Matsumura left the grounds of the Manzanar War Relocation Center in California with a group of fishermen who had set out for the lakes of the Sierra Nevada.

After a few days, Mr. Matsumura, 46, broke off from the group to paint and sketch. He had taken up art in Manzanar, one of 10 internment camps the United States government set up in the wake of the Japanese attack on Pearl Harbor, and where Mr. Matsumura and his family had been forced to relocate by the Army.

A sudden storm moved in. When it subsided, the fishermen went looking for Mr. Matsumura.

His body was found a month later, near a lake on Mount Williamson, California’s second-highest peak. But he was too far from safe terrain to be moved, and his remains would stay buried under gray boulders for decades, until last October, when two hikers who had gone off track stumbled upon them.

On Friday, officials from the Inyo County Sheriff’s Office and the Manzanar National Historic Site confirmed in a statement that the remains belonged to Mr. Matsumura.