He was awarded the Purple Heart and Silver Star posthumously, but for some reason the family never was told about the Silver Star and it was never sent to them, Fike said.
Merin's mother never talked in detail to her daughter about Markel.
"It was a very difficult topic for her. When my father died, she was seven months pregnant with me," Merin said.
Her mother briefly remarried when Merin was 10 but her stepfather died three years later, Merin said.
Her mother moved into the apartment in 1960 and may have placed the Purple Heart in the locker then, Merin said. Her mother lived there until 1975 before moving away, and Merin's aunt lived there until 2005. Another aunt lived there until 2009.
They never spoke about what was in the locker, and the family must have missed the box when they took away the aunts' possessions in 2005 and 2009, Merin said.
Merin said that in addition to the Purple Heart, which Pike kept for framing, the box contained letters and other papers, and her father's Jewish prayer book.
"I found it very hard to look at. A lot of them were condolence letters," she said.
Merin's mother was told about the discovery of the Purple Heart but didn't live to see it — she died Feb. 1 at age 94.
Associated Press writer Christopher Weber contributed to this story.