In August 2004, Iris Chang flew to Louisville, Kentucky, to meet a Bataan veteran. Soon after arriving, she collapsed in a hotel room but later managed to have herself admitted to a psychiatric hospital. The doctor diagnosed "brief reactive psychosis".

"The Iris Chang I first met in October 1988 never came back," Douglas said.

Iris Chang killed herself on Nov 9, 2004. Messages of condolence flooded in, but her death also provided an opening for her detractors, who claimed that she had written The Rape of Nanking in a delusional state.

This is an assertion that her husband rejects. "Iris completed The Rape of Nanking in early 1997, but never showed any real signs of mental illness until 2004," said Douglas, who sees no direct connection between his wife's suicide and the horrors she endured writing the book.

"Rather than upsetting her, seeing the photos and reading the materials energized her and drove her to do the best job she could to tell the stories."

Ying-Ying Chang believes the antidepressants her daughter was taking heightened the suicidal tendencies she already harbored.

In September 2005, nearly a year after Iris Chang's death, her parents were invited to Nanjing for the unveiling of a bronze statue of their daughter at the city's Memorial Hall for the Victims of the Nanjing Mass-acre.

"I left China in 1949 with my parents when I was 9 and didn't return to Nanjing until 2005," Ying-Ying Chang said.

"We told our history to Iris, who then, through her work and her book, brought us back to where we had come from."

Since then the couple, who have set up the Iris Chang Memorial Fund in the US, have visited China seven times.

"We sponsor US high school teachers to travel here and learn about the Nanjing Massacre," Ying-Ying Chang said. "It's a crucial chapter of World War II that is almost completely missing from history textbooks in the US, and from people's consciousness. There are less-ons to learn."

Toward the end of her book, Iris Chang wrote, "Japan's behavior during World War II was less a product of dangerous people than of a dangerous government, in a vulnerable culture, in dangerous times, able to sell dangerous rationalizations to those whose human instincts told them otherwise."

Every time Iris Chang's parents visit Nanjing, Yang accompanies them.

"For a very long time in China, discussion of the Nanjing Massacre was not particularly encouraged, partly because of the shame involved," Yang said. "Today, another type of shame, one that Iris instilled in me, propels me forward in my research into the massacre."

In 2007, Yang translated The Rape of Nanking into Chinese. He said he will never forget the scene of the young author before the memorial stone, the setting sun lighting up the stele and illuminating her features. It reminds him of Sunrise, a poem Iris Chang wrote for her high school magazine.

"Rosy luminance appears

Over the edge of the earth

Banishing all the darkness

To reveal a new day's birth ..."

Contact the writer at zhaoxu@chinadaily.com.cn