TOKYO (Reuters Life!) - Martin Davidson's German grandfather was a loud, gregarious and difficult man who exuded a coarse, but infectious, bonhomie. He also carried a sense of secret intrigue and forbidden knowledge that he appeared to enjoy.
It wasn't until after his death, though, that the UK-born Davidson finally learned the reason. His grandfather, the retired dentist, had also been an officer in the SS, the dreaded paramilitary unit that, under Heinrich Himmler, was responsible for numerous war crimes.
Armed with that knowledge, and his mother's assurance that her father, Bruno Langbehn, had nothing to do with the camps, Davidson -- by then a historian and documentary maker -- began a search for the man's hidden past, haunted by questions of how a blood relative could have been so seduced by Nazi ideology.
"The more I thought of him, the more I had a picture in my mind that he had been allowed to live for many, many years after the war with a kind of aura of unaccountability," Davidson said in a recent telephone interview.
"It was as if he'd thought he'd gotten away with it."
Davidson's quest, chronicled in "The Perfect Nazi, Uncovering My Grandfather's Secret Past," showed him how Bruno grew obsessed with the Nazi Party as a young man in economically struggling post-World War One Germany.
Joining as early as 1926, when still a teen-ager, Bruno tied his fortunes to the group more tightly with each step up through the hierarchy, drawn partly by the heady sense that he was "in the driving seat of history."
There was also, Davidson said, an almost surprisingly ordinary feeling that his grandfather had used the Nazis like any other major organization, the way an ambitious executive might view his company -- as a way to get ahead.
"This was a key element of the Nazi story: men like him, who from day one worked incredibly hard to make the whole thing as dynamic and plausible and durable as possible," Davidson said.
"It was about letters of reference, it was about application forms, resumes and curriculums. It was about keeping your eye open to see where the power had gone... all very recognizable."
Following the war, Bruno returned to Germany from Prague, where he had been posted, with his family. Concealing his Nazi past, he resumed his career as a dentist and lived on until 1992, when he died at the age of 85.
Though his mother preferred not to think of the war, and apparently worried about the response of her friends to whatever Davidson's research might yield, her only comment before he began was that he should avoid sensationalizing things.
When Davidson got through piecing together the story, he told her what he had found.
"I think something snapped in her mind. She just said, 'Oh my God. You know what? Just... to hell with him. I've spent 50 years guarding his secrets for him. To hell with him,'" he said.
"I think she found it quite a cathartic moment."
Left at the end with both a feeling of satisfaction that he had brought Bruno, even symbolically, to account, and the inevitable discomfort of being related, Davidson said there were important lessons in Bruno's tale.
"As you're growing up -- and we live in financially uncertain times -- take a look at your own emotions and how people in politics exploit fear, racism, insecurity, nationalism," he said.
"Monitor these things in yourself and make sure you control them, they don't control you. Because in the story of my grandfather, you can see what happens if those emotions are allowed to produce politics."
Reporting by Elaine Lies, editing by Paul Casciato