JERUSALEM — For decades, Hinda Koza-Culp’s family clung to a black-and-white photograph and a haunting story: Her great-grandmother’s six siblings and parents were all murdered in the Holocaust, their names largely lost to history. Then last year, Koza-Culp typed her great-grandmother’s maiden name, Litvak, into an online database and discovered something she never could have imagined. Two of her great-grandmother’s siblings had survived. One of those siblings had a son living in Israel — and he wanted to talk. “We spent so many years apart, so many years not knowing each other,” Koza-Culp told NBC News. “To take that back,...