Shigeaki Mori, who survived the first American atomic bomb as a boy in Japan and then spent decades as an adult researching what happened to 12 American prisoners who were killed in the attack, an effort that led to a widely photographed, tearful encounter with President Barack Obama, has died in Hiroshima, Japan. He was 88. Read more:

President Barack Obama, wearing a dark suit, hugs Shigeaki Mori, who has thin white hair and is wearing a gray suit. Shigeaki Mori with President Barack...