Every weekend for more than 20 years, Shigeaki Mori sat in the hallway of his compact two-story home making calls to people in the United States, asking, "Do you have a family member who died as a prisoner of war in Japan?" 

He was searching for the families of 12 American POWs who died on Aug. 6, 1945, when the United States dropped an atomic bomb on the Japanese city of Hiroshima.

It was not until the 1970s that declassified U.S. documents indicated the presence of the POWs in Hiroshima on that day. In the 1980s, Satoru Ubuki, a local university professor found their names and passed them on to Mori, a keen local historian.