Last week, three members of the staff at Germany’s Federal Intelligence Service with suspected far-right connections were suspended, prompting an internal review by the agency. Just a few weeks earlier, 18 police officers in Germany were fired after participating in a group chat with far-right, anti-Semitic, and racist content.

All this comes less than three months after German prosecutors announced the arrest of 25 people, who stand accused of a bold plot by the far right to overthrow the German government. Among those arrested: an active duty soldier, a Russian citizen, and a German prince.

You’d be forgiven for thinking the MAGA run on the Capitol may have inspired the so-called Reichsbürger terror cell. But, in reality, German groups like these have been hiding in plain sight for years, enabled by a state that failed to grasp the magnitude of the problem—even after Germany’s biggest Nazi-terror trial since Nuremberg, which ended in August 2018 with a crashing disappointment. There is a lot to learn from that case, about the way Germany functions and why this keeps on happening. But let me start from the beginning.

Between 2000 and 2007 in Germany, seven small-business owners, Turkish and Greek in origin, were murdered. Because two of the victims owned food carts that sold “doner kebabs,” the Turkish street food wolfed down by revelers on their way home from the city’s nightclubs, the German media dubbed the killings the “Doner Murders.”

The police instantly suspected organized crime, most likely the Turkish Mafia. Yet the murders had all been carried out with a Česká 83, a rare, Soviet-era handgun from Czechoslovakia, equipped with a muffler: a strange choice of weapon for a Turkish trans-national crime organization. But nobody paid too much attention.

Meanwhile, about 470 miles north, on the island of Fehmarn, a popular camping destination with Germans, a woman with long, dark hair, who introduced herself to new friends simply as “Liesl,” was enjoying her vacation. There were group aerobics sessions, card games with neighbors, pit stops to the local doner-kebab shop, and cozy dinners outside the white caravan she shared with her friends Max and Gerry. The men, both tall and lanky with striking bone structures, were, like Liesl, around 30.

What German media dubbed the “Doner Murders” had all been carried out using a Česká 83—a rare Soviet-era handgun that was found in Beate Zschäpe’s apartment.

Juliane, a teenager who was camping with her family, became close with Liesl over the course of several summers. She later testified that Liesl was the kind of person always willing to lend an ear, and generous too, paying with 500-euro bills when they went out to eat. One time, Gerry relayed to Juliane how to make gunpowder, but the occasional odd moment was obscured by her otherwise fond memories of the time spent with Liesl.

Liesl also went by “Lisa,” “Susann,” and “Mandy,” among other aliases. But her real name is Beate Zschäpe, and she met Uwe Böhnhardt (“Gerry”) und Uwe Mundlos (“Max”) as a teenager in the early 90s. Germany had just been re-unified, and her hometown, Jena, like many others in the former East, was marked by disillusionment, lack of opportunities, and strong anti-immigrant sentiments. The trio met in a youth club and together joined a neo-Nazi network called Thüringer Heimatschutz, run by neo-Nazi and intelligence informant Tino Brandt.

Zschäpe was first linked to Mundlos, a mathematics professor’s son, but she moved on to Böhnhardt when Mundlos was away on a stint in the army. Leading psychologist Ulrich Sollmann, who reviewed court documents and videos and had access to Zschäpe’s written correspondence, said, “The three basically lived in a ménage à trois with changing sexual relations. I suspect that the men were emotionally weaker than her, which was reflected in their subtle dependency [on] her.” Sollmann added, “She clearly had a leading function. She had a very strong influence over these men.”

In 1998, Zschäpe rented a garage in which investigators found four pipe bombs and three pounds of TNT, and, with police on their tails, the group went underground. The National Socialist Underground (N.S.U.) was born.

A Wake-up Moment

On April 4, 2006, 39-year-old Mehmet Kubaşık, a father of three, was murdered in his convenience store, in Dortmund, North Rhine–Westphalia—also with a Česká 83. When a witness testified that she saw two men with light-brown hair, who looked to her like “Nazis,” police officers responded by presenting her with a photo spread of suspects: all were Mediterranean-looking men with dark hair.

Just two days later, 21-year-old Halit Yozgat was shot dead in his Internet café, in Kassel, Hesse. Yozgat, who had borrowed money from his father to open the café while attending evening school to earn his high-school-equivalency diploma, was the ninth victim.

For the Turkish community, long convinced that the killings were motivated by racism, Halit’s murder was the last straw. His family appealed to the authorities and organized a silent march in Kassel. Four thousand people took part. The police and prosecution, meanwhile, were focusing their investigation on the victims’ relatives.

While the press took no notice of the protests, the hunt for the “Doner Murderer” was now gaining national attention. The reports even made their way to Zwickau, a small East German town in Saxony, where Zschäpe shared an apartment with Böhnhardt and Mundlos. Someone in the household kept newspaper clippings about the case.

Zschäpe, Uwe Böhnhardt, and Uwe Mundlos, of the National Socialist Underground.

They had lived there for the past five years, in cookie-cutter German fashion, orderly and predictable. Just like on Fehmarn, Zschäpe was a popular fixture in the neighborhood. Böhnhardt and Mundlos weren’t as talkative, so she explained to the neighbors, “One is my boyfriend and the other is his brother.”

Meanwhile, in Munich, the investigation had made no progress. The police department’s operational case-analysis unit requested assistance from America’s F.B.I. In his six-page report, supervisory special agent and profiler Robert Morton concluded that “the offender has a personal, deep-rooted animosity towards people of Turkish origin.” Still, the German investigators did not change course.

When a witness testified that she saw two men with light-brown hair, who looked to her like “Nazis,” police officers responded by presenting her with a photo spread of suspects: all were Mediterranean-looking men with dark hair.

Another four years went by. On a warm, sunny morning on Fehmarn, in the summer of 2011, Zschäpe was getting ready for a group aerobics class. At the site, a crew from NDR, a public-television station, was setting up cameras to film segments for a promotional video of the island.

This video, which aired on the program Mare TV in September 2012, will be revisited countless times, by journalists and stunned citizens, zooming in on the woman in the back row, wearing a black tank top and sunglasses, working up a sweat: Zschäpe. It raised a question that remains unanswered to this day: How could a neo-Nazi terrorist, on the run for 13 years, be filmed voluntarily, unfazed by the possible exposure of her perfectly constructed double life?

On November 4, 2011, Böhnhardt and Mundlos robbed a bank—their 15th—but this time the police gave chase, and investigators soon found the two men in their white camper van, dead, with a pump-action shotgun next to Mundlos.

Back in Zwickau, Zschäpe dropped her cats with a friend, set their apartment on fire, and went on the run. In the burned-out house, investigators found a Česká 83 that was later linked to the killings. Zschäpe mailed a dozen copies of the group’s confession video (“N.S.U. is a network of comrades guided by the principle—actions instead of words,” it began) to media outlets, the Turkish consulate general in Munich, and the left-wing party Die Linke, before eventually turning herself in at the police station in her hometown of Jena.

Zschäpe set her apartment in Zwickau, Germany, on fire and went on the run.

In the trial that followed, it became apparent that the trio were supported by at least 30 accomplices, some of who provided weapons, identification papers, shelter, and money. But prosecutors charged only four of them. Zschäpe, who, from what is known, didn’t commit any murders herself, was charged as an accomplice in all crimes committed by the group.

News of N.S.U. was a wake-up moment for Germans, comparable in impact to the 2017 “Unite the Right” rally, in Charlottesville, Virginia. The state terror trial, starting in May 2013, suggested that while Germany may have de-Nazified culturally, its institutions and investigative authorities were “in urgent need of reforms,” according to the United Nations Committee on the Elimination of Racial Discrimination in 2015. The German government responded by saying that a parliamentary investigation into N.S.U. had found that there was no evidence of “institutional racism among investigation authorities.”

When the court’s written verdict was submitted, almost two years after the end of the trial and one day before the deadline, 19 lawyers for victims’ families, in a joint statement, criticized the court for failing to recognize the reach of the terror network. They described the verdict as “formulaic, ahistorical and cold.” It showed “that the judges of the Munich Higher Regional Court had no interest in resolution, and that they stand before those affected with horrid indifference.”

Victims’ relatives were disappointed by the outcome of the trial, said Turan Ünlücay, who represented the family of Mehmet Kubaşık, the murdered convenience-store owner: “The court failed to investigate further accomplices and the state’s shared responsibility was ignored.”

Zschäpe was sentenced to life in prison. Her lawyers appealed and, after requesting an “accommodation close to home,” she was moved to a prison in Chemnitz, Saxony. Germany’s Federal Court of Justice rejected her appeal in 2021. Her lawyers responded by issuing a complaint, which was overruled by the Constitutional Court last year.

In the 11 years since the case became public, more than 40 Germans have been killed at the hands of far-right extremists, among them a conservative politician and proponent of Merkel’s refugee policy named Walter Lübcke, who was assassinated by a neo-Nazi who had been previously surveilled by the authorities.

For those who knew “Liesl,” “Max,” and “Gerry,” the revelation about their double life was hard to digest. “To this day I can’t understand it,” Juliane testified in court. “I trusted them to 100 percent. Then I understood that they lied to me this entire time, conned me.”

Hiding behind a cheery bourgeois façade, the cell got away with 10 murders, three bomb attacks, and the bank robberies.

At its worst, Germany has lived a double life not unlike N.S.U. On the face of it, the country is a model for overcoming the past, but on closer inspection, something more sinister appears.

Antonia Woloshyn is a New York–based freelance journalist. Her next project is a podcast series about the N.S.U. murders