When Martin Davidson was growing up in Scotland, he thought his grandfather Bruno Langbehn was just another pensioner — he'd been a dentist in his native Germany, he liked a nightcap of schnapps, he was full of colorful stories and very proud of his grandson.
But when Davidson became older, he started to notice a darker side to his grandfather.
"There was an aura of forbidden knowledge that he exuded," Davidson tells Guy Raz, host of weekends on All Things Considered. "He had a swagger to him, you know, he enjoyed having the last word in an argument. And even, even as a child, I could do the math. I could work out, well, what age was this man when all of that Nazi stuff was happening?"
Davidson tells the story of his search for answers in a new book, The Perfect Nazi: Uncovering My Grandfather's Secret Past.
Bruno Langbehn died at the age of 85, just after the Berlin Wall came down, and it wasn't until after the old man's death that Davidson says he put all the pieces together.
"And alongside being devastated by my discovery, I was also dumbstruck at how stupid I'd clearly been, how unobservant I'd been all those years in his company," Davidson says.
Davidson pried one more damning admission out of his mother after his grandfather's death: Yes, Langbehn had been a Nazi, but more than that, he had been in the Schutzstaffel or SS. His dedication to the aims and ideals of Nazism had been absolute.
"I discovered that he'd joined the Nazi party at an astonishingly early age, barely 18," Davidson says.
Langbehn was the proud recipient of a Gold Honor Party Badge, the decoration given only to those who'd supported the Nazis in their early days on the fringes of power.
He'd been a storm trooper with the SA, beating up communists in the streets of Berlin before joining the SS and taking over the management of the city's dentists. And he only took off his uniform days after Germany surrendered in 1945.
Davidson calls his book a sort of reckoning, a calling to account of the man who never appeared to repent his actions in the slightest. "I think he was unaccountable," Davidson says. "He'd felt he'd got away with it. And posthumously, my book is an attempt to redress that."