Philippe Sands first met Horst Wächter in 2012 as a result of his first book, the acclaimed East West Street. This hybrid of history and memoir centered on the city of Lviv (also Lvov, Lwow, and Lemberg) in the former Austro-Hungarian province of Galicia, where Sands’s own (Jewish) ancestors had lived, and where the two (Jewish) men who gave the world the contrasting concepts of genocide (Rafael Lemkin) and crimes against humanity (Hersch Lauterpacht) also grew up. A big part of that story was Hans Frank, the Nazi ruler of Galicia, responsible for the murder of hundreds of thousands of Jews. In writing his book, Sands became friendly with Hans’s son, Niklas Frank, who had written a memoir condemning his father. Niklas told him about Otto Wächter, Frank’s second-in-command, and about Horst, the fourth of Otto’s six children, whom he knew slightly. Horst, Niklas warned, had a friendly view of his father—but he added that Sands would like him.

Niklas was right—an initial meeting with Horst led to a public discussion with the two sons of prominent Nazis, which was made into a film. As Sands continued to learn more about Otto, he turned his findings into a podcast for the BBC, using Otto’s post-war experiences to discuss the so-called Ratline, the help the Vatican provided former Nazis in fleeing Europe to the Middle East and South America.

The podcast in turn led to further discoveries (as listeners wrote in with information) and to a sharpening of the tension between Sands and Horst. The Ratline: The Exalted Life and Mysterious Death of a Nazi Fugitive thus necessarily focuses on the many layers of its coming to be; alas, Sands is not always a good enough writer to pull off the complicated structure required by a story about the telling of a story. Many of the turns in his investigation are introduced awkwardly. Chapters regularly end with clunky “cliffhangers” like this one: “Who was Bishop Hudal, and what exactly was his relationship to Otto? It was to that question that I would now turn.”

Still, Sands (and his team of researchers and assistants) is a good investigator. He describes Otto’s early days in the (then-banned) Austrian Nazi party, his role in the attempt to assassinate the Chancellor Dollfuss, his years in exile/hiding in Germany, followed by a triumphant return to Austria after the Anschluss, and meteoric rise in the apparatus of the Final Solution, first as a state secretary in Vienna (he fired hundreds of civil servants for being Jews, Mischlinge, or otherwise “politically unsound”), then as Frank’s number 2 in Kraków, and finally as governor of the District of Galicia, based in Lemberg.

Yet for Sands Otto’s wartime record matters primarily because of what happened afterward. In May 1945, Otto went underground; Sands finds out where he was, who he was with, and how he managed it. He tracks his movements in the years from 1945 – 49 (sussing out all his hiding spots in the Austrian Alps, including secret conjugal visits) and learns his daily routines after making his way to Italy in the last year of his life. He knows where Otto hid in Rome, under what name, and who he saw. To do so, he relies on Otto’s address book (cracking its rudimentary code), but mostly relies on his wife Charlotte’s papers, all of which Horst lets him see. (They are extensive: almost 9,000 pages of letters alone.) Charlotte destroyed her husband’s papers at the end of the war, which of course frustrates Sands, but he makes good use of this seeming obstacle by making the book as much about Charlotte as Otto. The portrait of their marriage is fascinating: Charlotte was tormented by her playboy husband’s many affairs, yet she was also his staunchest defender. She had been a committed Nazi from the early days; students in the ramshackle language school she ran decades after the war testify to Sands that she was not shy with her opinions.

Sands really homes in on Otto’s last days, in July 1950, when he suddenly fell ill and died from a mysterious illness. Horst, after a lifetime of hearing it from his mother, believes his father was poisoned. By whom? Maybe the Americans, maybe the Soviets, maybe the Jews. (That phrasing tells you everything you need to know.) Horst knows from his mother that the corpse, which she saw shortly after death, turned mysteriously black. How could a man like Otto—fit, a keen sportsman, who exercised every morning and swam in the Tiber—suddenly fall deathly ill? Surely it means something that he wrote to Charlotte about the enemies he suspected were following him. Horst is convinced that his father was murdered, and that he didn’t deserve it. After all, he was “a fine and decent man,” as a Ukrainian veteran of the Waffen-SS Galicia Divisions says, at a reunion attended by Sands, Niklas Franks, and a “beaming” Host.

At the very last stage of his lengthy investigation, on a visit to Rome to see the places Otto frequented in his last months, Sands is joined by another friend, a Spanish writer of nonfiction novels about the repercussions of the war. It’s pretty clear this must be Javier Cercas, and I don’t know why Sands is so coy about it, since he cites Cercas by name in one of his epigraphs, right below a typically forbidding passage from Isiah about the way violence will be passed down to the children of those who perpetrate it. Sands asks his friend why he came along. Why has he made Sands’s obsession his own? “It is more important to understand the butcher than the victim.”

Sands’s gloss—“A pretty phrase, and one that seemed true”—is evasive in a way belied by the doggedness of his investigation. He clearly believes in understanding the butchers, and I don’t know why he feels the need to hedge. Me, well, I think Cercas and Sands are full of shit. It’s sentiments like this, usually accompanied by a dutiful nostrum about knowing the past to avoid its repetition, that have led to our culture’s insatiable Nazi thirst.

Besides, Sands learns almost nothing about Otto’s motives. The villain of the story remains opaque. We learn as clearly as we can what Otto did during the war, how he came to his conviction in the cause, and how he spent his years on the run. But what he was thinking of when he organized the ghetto in Lemberg and oversaw the deportations and murder of so many thousands of Galician Jews is a mystery. Did he believe what he said to Charlotte and what she said to Horst, that he felt a duty to handle the situation he was entrusted with as efficiently and humanely as possible? Is this nonsense self-delusion or cynicism? Sands understands what a butcher can do, but not why they did so.

The person whose motivations we do know something about is Horst, who comes across as a riveting and exhausting combination of reasonableness and monomania. He deplores the genocide, and he is willing to look into his family’s past, to the point of being shunned by his siblings and cousins. But he doesn’t deplore it that much. What he really hates is his father’s being lumped in with obvious criminals like Frank, Himmler or Arthur Seyss-Inquart (Reichskommissar of Occupied Holland, and Horst’s godfather). Horst is boring the way only someone who cannot come unstuck from a belief system can be. He insists that his father was a different kind of Nazi, who never had anything to do with the unpleasant aspects of genocide (and merely accepted the benefits that accrued to him from it as compensation for his mission) and sought only to make life more bearable for those terrible sufferers. To his credit, Sands is infuriated by this equivocation, and his portrait of Horst, who can’t help but come back to Sands every time he has pushed him away, is fascinating. Every time we think he is deserving of sympathy, Sands shows that he is not.

His portrayal of the Vatican is less compelling. Clearly Bishop Hudal, who befriended Otto and helped various other Nazis escape Europe, was at best a disreputable figure. And the Vatican’s stonewalling of Sands’s request to consult Hudal’s papers does not inspire confidence that it is willing to deal with its past in good faith. Sands never makes a blanket statement about the Vatican’s relation to Nazism—possibly because there isn’t one to make, and possibly (rightly) because doing so would result in a different kind of book. Sands has more to say about the Vatican’s ambiguous postwar relationship to American intelligence than about what the Church did or didn’t do during the war. Otto, it turns out, was spying for the Americans, through the intermediary of Hudal, further evidence of America’s immediate post-1945 pivot to the Cold War. In those first years after WWII, being anti-Soviet (and Otto was more enraged by communism than by anything else) was a lot more important to the US than having been a Nazi.

I appreciate what Sands has found out about Otto’s life and death. But I did weary of Sands himself. Although I read The Ratline avidly—it is as suspenseful as John Le Carré suggests in his blurb—I was irritated by the privileged world Sands inhabits, which he flaunts at every occasion. He gains access to every institution, consults with every kind of specialist, finds every door open to him. All in a good cause of course. But it’s all very Davos, if you know what I mean; it got to the point where I wondered about the patients the various liver specialists Sands consults weren’t seeing when they were being interviewed by him about the body’s metabolism of poisons. Put it this way: Le Carré doesn’t just blurb the book; he was Sands’s neighbour, too. I started to find the British and European elites of Sands’s milieu uncomfortably similar to the Nazi elites that had such a marvelous time enjoying the best of all things and thinking the best of all thoughts. Not that Sands and his peers are fascists. They definitely are not; I recognize that I am doing him an injustice here. But they too have drunk the Kool-Aid of their own specialness, it seems to me. Had I sensed that Sands had any self-awareness about this possibility I would have felt better about the dark fascination—the consumption of atrocity; the butcher love—that The Ratline too often incites.