The strange case of the murder of a young British woman in Japan is the focus of Parry's People Who Eat Darkness: The True Story of a Young Woman Who Vanished from the Streets of Tokyo—and the Evil That Swallowed Her Up.

Did you intend for your book to be as much a story about Japan as it is about the murder of Lucie Blackman?

What compelled my attention over 10 years was the way that this story touched on so many different aspects of life. It began as a mystery story: what had happened to Lucie? But to answer that, I had to delve into what she was doing in Japan and the so-called “water trade” of hostesses and Japanese nightlife. It became a story about a loving but troubled family hunting for their daughter in a strange and unfamiliar place, and a detective drama about a difficult police investigation. Eventually a man was arrested and tried, and it became a courtroom drama, and a story about an extraordinary criminal. But it also revealed the remarkable differences between the Japanese police and courts, and the justice system we know in the West.

How long had you lived in Tokyo before you began covering the Blackman case?

I’ve lived here for 17 years. Lucie disappeared in my sixth year in Tokyo, so by that time I knew my way around. But I was still amazed by much of what I discovered in investigating this case. It was like lifting up the stones in a familiar garden and finding bizarre and unsavory creatures living underneath. I’ve tried to smuggle into the book my own perceptions and insights into Japan, the country that’s become my home, without overwhelming the story and the people in it.

Lucie’s father, Tim, and her sister, Sophie, both played prominent roles in the media throughout the investigation. Do you think their media presence helped or hindered the case?

If the Blackman family, and particularly Tim, had not dug in their heels and made a nuisance of themselves, Lucie’s body would never have been found, and Joji Obara might still be raping women today. Tim became the object of intense criticism, even hatred, but no one should forget his role in resolving this terrible case. Thanks to his raw determination, the case was even raised in a summit meeting between the Japanese prime minister and Tony Blair. The Japanese authorities didn’t know what to make of him—a conventional Japanese family in such circumstances would simply have shut up and left everything to the police.

There are still questions surrounding Joji Obara, the man tried for killing Lucie. What is it about this case, and Obara, that makes it so difficult to pin down?

Joji Obara is the black hole at the center of this story. In the end, I began to think that this is the key to understanding him; that, rather than being positively “evil,” he is best understood in terms of negatives—an absence of close relationships, an absence of human values, a terrifying void.