This article was adapted from “Nazi Hunting: A Love Story,” by Jess McHugh, published March 13 by Everand.

It was a chilly March day in Cologne in 1972 when a group of five set off in pursuit of an outlandish goal: kidnapping former SS officer Kurt Lischka. The team hoping to snatch Lischka in broad daylight was no highly trained team of undercover agents. Instead, it consisted of a political scientist, a photographer, an Orthodox Jewish doctor and the group’s leaders, Beate and Serge Klarsfeld. Several of them were Holocaust survivors.

The Klarsfelds were a semi-vigilante duo dedicated to bringing Nazi war criminals to justice. Serge, a Romanian-born French Jew, had lost his father to the death camps at Auschwitz. His wife, Beate, a German woman whose father had voted for Adolf Hitler and fought for the Wehrmacht army, sought to make amends for the sins of her family by refusing to stand by while Nazi criminals lived with impunity in postwar Europe.

Focusing first on war criminals who had acted in France, the Klarsfelds had spent years doing the slow, meticulous work of building a case against the top Nazis. The young couple had spent much of their newlywed years together in the dusty archives of the Center for Contemporary Jewish Documentation, the archival wing of the Holocaust memorial in Paris. Sorting through box after box of paperwork, the Klarsfelds pored over the signatures and initials on telegrams, letters and military orders from the war. They tried to determine which signatures showed up most frequently — anything that would help them reconstitute the chain of command that orchestrated the deportation of some 76,000 Jews from France. One name came up again and again: Kurt Lischka.

Lischka rose quickly through the ranks of the Nazi hierarchy after joining the SS in 1933. He made a name for himself as an expert on “Jewish affairs,” and in 1938 — a year he was promoted three separate times — he oversaw the mass deportations of German Jews following Kristallnacht, a series of violent attacks against Jewish people and property. That same year, Lischka deported more than 20,000 Jews from Berlin to the eastern border, where many of them died of starvation or exposure to the cold, a consequence that one of Lischka’s supervisors called “ingenious.”

Lischka was transferred to Paris after the Germans occupied France in 1940. He would have discretion over the French police, decide the prison conditions for French Resistance members, organize extrajudicial killings and spearhead roundups of Jewish residents. Documents found by Beate showed Lischka had been a zealous member of the SS, urging his superiors — including Adolf Eichmann, architect of the Final Solution — to take more extreme measures against Jewish people in France. In letters to Eichmann, Lischka complained frequently that the Jews weren’t being deported fast enough, warning that these delays both showed a “weakness on the part of the Germans” and allowed more time for French civilians to try to intervene on behalf of their Jewish friends and neighbors. The extermination of all Jews must go ahead without exception, Lischka insisted, writing, “Otherwise, the French will think that apart from the Führer himself, there are no German antisemites.”

Lischka was still living in Germany in the 1970s and hadn’t even bothered to change his name. The Klarsfelds’ plan was to grab him as he came home for lunch and toss him into their getaway car, a rented Mercedes coupe. If German authorities wouldn’t prosecute him, they would deliver Lischka to the doors of a French police prefecture in Paris.

Far-fetched as the plan may seem, there was some precedent for illegally capturing Nazi criminals and then legally trying them in a court of law. In 1960, Mossad agents snatched Adolf Eichmann from a bus station in Argentina, sedated him, and smuggled him on a plane back to Israel, where he stood trial. He was convicted in 1961 and executed by hanging the next year.

The motley squad spent several days preparing. A rehearsal in a nearby forest went well, although the doctor — who was role-playing as Lischka — accidentally ended up locked in the trunk.

The Klarsfelds, sometimes photographed in tailored trench coats, looked like a nerdier Bonnie and Clyde, updated for the 1970s. Serge, 36, had a round face, square tortoiseshell glasses and a mass of thick, curly hair. Beate, 33, was always well dressed with her cropped hair in place. She had spent days clandestinely following Lischka, tracking his every movement to learn which tram he took to his job as an executive at a shipping company, what time he returned to eat lunch with his wife, and when he headed back into the office.

On the day of the abduction, the would-be kidnappers set off on their ambitious mission armed with syringes filled with tranquilizer, bulbs of chloroform and a heavy bludgeon. Around noon, Lischka appeared. The 6-foot-2, nearly 250-pound former Nazi would not be easy to subdue. He breezed past the group, carrying his briefcase on his way home for lunch, just as he had done for many years. Had he carried that briefcase to the Gestapo office on rue des Saussaies in Paris, where the cries of the tortured could be heard from the street? Had he conducted his work with the same dispassion he applied to his career as a businessman?

When Lischka walked by, two of the men each took him by an arm while a third began striking him over the head with the bludgeon. Lischka crumpled to the ground, screaming for help: “Hilfe! Hilfe!” Hearing his cries, a nearby policeman ran up to the group as they were trying to bundle the Nazi into the two-door sports car. Sensing that the mission was doomed, the crew released Lischka, jumped into the car, and threw his black hat after him as they sped away. Beate, having gone unnoticed, stayed behind.

Just because they did not succeed in capturing Lischka didn’t mean they failed. Several days later, Beate went to the prosecutor in Cologne. She took full responsibility for the kidnapping and gave him their entire case file on Lischka, explaining why they had tried to bring him extrajudicially to France. Arrest me for attempted kidnapping, she told him, and you will put a young mother in jail while letting a Nazi roam free. The prosecutor pulled a warrant for her arrest out of his desk and took her into custody.

The strategy worked: Her arrest provoked outrage across Germany and France, giving her and Serge a platform to draw attention to Lischka’s crimes. Within a few weeks, Beate would be provisionally released, but each day she spent in jail was another day she was in the headlines, talking about the blood on Lischka’s hands and pointing to the documentation that she and Serge had so meticulously collected.

No one could say their accusations were baseless: The Klarsfelds had only to point to the hundreds of pages showing Lischka’s signature on orders for deportations and antisemitic directives. Where once the couple had been met with suspicion and even derision, they now saw an outpouring of sympathy. The German public could no longer dismiss the Klarsfelds’ actions as mere media stunts or the ravings of overexcited youths caught up in the protest spirit of the 1960s.

As people heard about their cause, more allies joined them. The Klarsfelds began to gather a growing group of friends and supporters who were ready to make similar sacrifices in the pursuit of justice. Many of these allies were survivors too. Like Serge, they had not forgotten what they suffered at the hands of the Nazis, and they had no interest in moving on until those responsible were hauled into court. Jews who had spent years running from the Nazis were now the ones in pursuit.

Because of the Klarsfelds’ constant pressure on authorities, a treaty allowing for Nazis to be tried in Germany was finally ratified in 1975, but no major indictments came down immediately. In the meantime, the Klarsfelds had added two other names to the list of people they wanted to see prosecuted in Cologne: Herbert Hagen and Ernst Heinrichsohn, leaders of the deportation of French Jews. The Klarsfelds used a two-pronged approach in their quest for convictions: They gave every document they collected proving the three men’s implication in the Final Solution to both the Cologne prosecutor and the media. As the prosecutor continued to drag his feet, journalists for newspapers, radio and television ran stories about the men. The Klarsfelds also sent much of their documentation to nearly a thousand other people, including politicians, lawyers and academics, hoping to drum up support for their cause.

All told, Beate and Serge would have to wait nearly a decade from the start of their pursuit to the trials of Lischka, Hagen and Heinrichsohn. During that time, a number of their friends — including concentration camp survivors, former French Resistance members and a rabbi — would do jail time in Germany for their roles in protests against the former Nazis.

When the historic trial finally arrived in 1979, Serge, now a lawyer, represented nearly 300 plaintiffs, all victims of the Holocaust in France. Since the charge was not crimes against humanity but just accessory to murder, the maximum sentence was 15 years. Lischka, 70, would receive a sentence of 10 years. The jury, composed mostly of Germans in their 40s, represented a generation of children judging their parents. For the Klarsfelds — and especially for Beate, a German of roughly the same age — this was a major victory.