In The Ratline, author Philippe Sands traces the life and mysterious death of a Nazi mass murderer

In his latest book, The Ratline, British author Philippe Sands pieces together the life and death of Otto von Wächter.

Wächter, a high-ranking Nazi officer, was indicted on war crimes for his role in the mass murder of more than 100,000 Polish citizens but escaped capture and trial until his death under mysterious circumstances in 1949.

The story is told, in part, through Wächter's son, Horst, who shared a treasure trove of family letters, documents and diaries, dating from 1929 to 1949, with Sands.

Sands spoke with Day 6 host Brent Bambury about his new book, his relationship with Horst Wächter who, to this day, denies his father's role in the Holocaust, and focusing his book on a perpetrator rather than their victims.

Here is part of that conversation.

We just heard you speaking with Horst Wächter, the son of notorious Nazi Otto von Wächter, and it sounded like you were friends. Is that how you would describe your relationship? 

Well, we are sort of. I'm very fond of Horst, and curiously, I feel protective because I think I've come to understand he is like a damaged child. But I don't like some of his views and I don't like his sense of denial about what his father did. But I don't think he's a bad person. He's not a Holocaust denier. He's not a racist or an anti-Semite. He is a sweet person looking for the good in his father. 

The evidence against Otto von Wächter is solid. As a Nazi governor, he is implicated in the murders of tens of thousands of Jews, among them your grandfather's family. It is not questionable. Did you ever lose patience with Horst, with that repetitive claim that his dad was a good man? 

Indeed, it is not questionable. The evidence is absolutely overwhelming. He was indicted for mass murder, probably more than half a million people. And if he had been caught and tried, I have no doubt he would have been convicted and sentenced to death.

I first met Horst in about 2011, so it's been about 10 years. We remain in good relations and we're in contact quite a lot, even though our views are different. I try to maintain my cool when I'm with him, even if he upsets me sometimes. 

I did once lose my rag, as we would say in London. It was the moment where Horst had said to me, "You know Phillippe, there's no proof, there's nothing." Finally, I had found in Lviv, in Ukraine, the act of indictment by the Americans and the Polish authorities — mass murder, more than 100,000 Polish citizens — and I showed it to him.

He looked at it. He sort of went, "Mmm hmm." And I said, "What do you mean, mmm hmm?" And he said, "Well, it doesn't prove anything. This is a Soviet document. It's a concoction."

I want to also understand Horst's motivations for speaking with you, because many of his family were against it. And Horst made available to you this treasure trove of Otto von Wächter's family's letters, documents and diaries and photographs and even audio recordings. Can you describe this trove, how big it is and the implications of it? 

Horst was born in 1939, so you get a sense of his age. He lived through the war as a young child. As he said to me, he hardly knew his father, but he knew his mother very well. She lived until 1985. Otto dies in mysterious circumstances in 1949, and it's very obvious that Horst really loves his mother. And his mother, Charlotta, loved him. 

He was, if you like, the chosen child out of the six. And she bequeathed to him the family archive, and it resides still today in the Schloss — the castle — where he lives. At some point in the filming of the BBC documentary, My Nazi Legacy, Nicholas Frank, the son of Hans Frank, who had been Adolf Hitler's lawyer and was hanged at Nuremberg for mass murder, said of Horst, "You know, he could be a new kind of Nazi." And I disagreed with that. 

Horst got very upset and he said to me, "How can I prove that I'm not a Nazi?" And I'd seen one or two items from this vast trove — all the letters, the diaries, the photographs, correspondence, everything between his mother and father from 1929 to 1949 — and I said, "You know what, why don't you give that to a museum? Why don't you give it to the Holocaust Museum in Washington, D.C.?"

He said, "Terrific idea," and he did it. And then he said, "Would you like a copy?" I said, "Sure, why not?" and a USB stick wound its way through my letterbox in London about two weeks later. 

[I] put it into the computer, and it was extraordinary material because the thing to understand about this book is it is, in part, the story of the horrors perpetrated by Otto von Wächter. But it's also a love story, the relationship between Otto and Charlotta, which is very central for me. In fact, I would say Charlotta Wächter is the beating heart of the book. There are a couple of crucial years that are completely missing in her diaries, which I suspect may not just be an accident, that they will have been destroyed. But for the most part, the material is there.

And if you like, they are damaged and destroyed by their own words because as the acts of killing are going on, she's celebrating the glories of life and he's writing about the absence of Jews to put powder on the tennis court or whatever. I mean, it's pretty shocking stuff.

How conscious was Horst of what you lost when your family was sent to the death camps by his father's administration? 

I think to understand Horst, the remainder of his life — 75-plus years — is about reconstructing that idyllic past and wishing that in some way it could be once more. 

At all times, when I'm with Horst, I'm very conscious that Horst's father was responsible for the extermination of my grandfather's entire family. But I'm equally conscious of the fact that Horst is not responsible for what his father did. 

What he's responsible for is recognizing the crimes of his father, and this is something he will not do and that is problematic. He takes refuge in the idea that [his] father never actually killed anyone personally, and that's his escape route as the child. And it's a complex situation. 

In the opening and closing pages of your book, you have a quote from Javier Cercas, the Spanish writer that you just mentioned. It reads: "It is more important to understand the butcher than the victim." What does that mean to you? 

Well it was said to me. It was incredible, actually. It was in the Vatican. Javier and I were sitting together in the Sistine Chapel and I said to him, "Why are you so interested in the Wächters, Otto and Charlotta?" And he said, "Because it's more important to know the butcher — the perpetrator — than the victim."

I thought that was significant because the heart of this book, in a sense, is to understand how can reasonable, cultured, intelligent, highly-educated people like Otto and Charlotta Wächter get involved in mass murder? It's obviously a huge question. 

I've written East West Street, and The Ratline, really to honour my grandfather who I was very, very close to. It is, you know, his dignity and his memory that is a beating heart of this story. But I can quite see some would be troubled by the idea that I'm trying to put the accent on the perpetrators rather than the victims, which is, of course, not my position.

Written by Jason Vermes. Produced by Pedro Sanchez. This Q&A has been edited for length and clarity.