“I’ve told you three times now, I don’t remember!” Bodief said.

In fact, he did, and once his distaste for the court had registered with everyone in it, he said that Mohammed had been “impulsive” and “hotheaded,” but that this hardly distinguished him from his peers. “He was just a young guy, he just wanted to have fun more than anything else,” Bodief said. “The boy was never dangerous,” he added, and the plaintiffs’ lawyers were suddenly outraged. “The ‘boy!’’ one of them shouted. “He’s got holes in his memory except when it comes to singing the praises of Mohammed Merah!”

Later, I followed Bodief outside and found him smoking a cigarette on the courthouse steps. He was friendlier than he’d been on the stand. Abdelkader had a “nasty look” about him, he said, but Mohammed hadn’t been that way. “He was a good kid,” he told me with a shrug.

Nasser, Bodief’s 48-year-old brother, was a compact and more polished-looking man. He came to court in a cap, sport coat, and black brogues. But he was no less prickly on the stand. Mohammed, he said in a brief opening statement, had been “a kid from a bad neighborhood who wanted a shot, like others do.” Les Izards was a hard neighborhood—“a free-range zoo”—but if Mohammed had been radicalized, it was neither the neighborhood nor Abdelkader that had done it. Mohammed was “a kid who went completely off the rails,” Nasser said. “And in my opinion, he went off the rails all alone.”

This contention appeared to be to no one’s liking. Investigators had at one point suspected Nasser of a role in funding Mohammed’s attacks, and though this proved to be false, the president questioned him as if he were still a suspect. He asked about a withdrawal of 5,000 euros from his business’s bank account. “I work hard and pay my taxes!” Nasser said.

An important function of the trial was to indict the violent norms and low expectations of Les Izards, here conflated with jihadism, that led them to miss the threat Mohammed posed.

A lawyer for the plaintiffs presented a printout of a photograph that had been found taped to the door of a cabinet in Nasser’s garage. It showed the weathered face of an old man in a black turban with a bushy beard and a dagger between his teeth. The photograph wasn’t accompanied by any Islamic texts or political statements, and its style was more National Geographic than jihadist-propagandist, but the man appeared to be a Taliban fighter. Why, the lawyer asked Nasser, was this photograph hanging in his garage? Nasser was angry and silent, and when the lawyer pressed him again, he responded simply, “I believe in one thing: work.”

One important function of the trial was to indict the neighborhood and the way everyone in it lived, the violent norms and low expectations, here conflated with jihadism, that led them all to miss the threat Mohammed posed. Nasser seemed to have grasped that, and he left the stand in a silent rage.

I followed him out. “Can I bother you?” I asked. “No,” he said, not stopping. I asked if I might come to see him in the neighborhood. “Don’t come to Les Izards,” he said. “It won’t go well for you.”

Zoulikha Aziri, the Merahs’ mother, appeared late in the trial to testify. She tottered to the stand in the center of the court in a formless robe and a tasseled yellow hijab that accentuated the almost complete circularity of her face. She looked more defiant than solemn, her features turgid with angry confusion. The president explained to her that, because she was the mother of the accused, the law exempted her from swearing an oath of honesty. “Which does not prevent you from speaking with candor,” he added. “Yes, yes, yes,” she said.

She made a brief opening statement, in hesitant French. “I think my son Abdelkader is innocent, he has nothing to do with the whole story that happened,” she said. “Mohammed—what hedid, Mohammed, it’s very, very serious. I didn’t know what he was going to do. He did what he did; now he’s dead.” A translator had accompanied her to the stand, and Aziri turned to the young woman to assist her with a brief word for the plaintiffs. “I present my apologies to the victims,” Aziri said. The president then questioned her about her life.

She was born in 1957 in a village in what was then French Algeria, the eldest of six children. She raised her siblings and received no schooling, according to an account she once gave to social workers. At 18, she was married without her consent to a man she had never met, selected for her by her stepfather. Her new husband, Mohammed Merah, was 15 years her senior and already married to a second woman, with whom he had several children. He worked in a factory in France, and Aziri followed him there in 1981, with her two children, a daughter, Souad, and a son, Abdelghani. A first daughter had died in Algeria, as an infant. It had been a sickness, Aziri thought, or perhaps her mother-in-law had poisoned the baby. “I don’t know,” she told the court dully.

Aziri arrived in the housing projects of Toulouse speaking not a word of French. She rarely left her apartment. By 1982, two more children had been born, a daughter, Aïcha, and another son, Abdelkader. Aziri apparently wanted no more. According to one social worker’s report, another Algerian woman told her of the existence of contraceptive pills, and she began taking them, although apparently without understanding how they worked. Mohammed was born in 1988.

Aziri’s husband beat her, and sent his earnings back to his other wife in Algeria. In 1992, she fled with her children to a women’s shelter, and a divorce was completed several months later, at which point whatever stability the family may have known seems to have evaporated. Aziri’s brother, who lived in Toulouse, imposed himself as a malignant patriarch, hectoring and beating his sister and her children. Her eldest son, Abdelghani, began drinking heavily; he too beat his mother and his siblings, especially Abdelkader, who was flagged by social workers as a “child in danger” as early as 1995. Various testimonies suggest Abdelkader was raped by an uncle, as well. As he grew older, the middle brother exhibited a distinct sadism and was once alleged to have tied Mohammed to a bed by his wrists and ankles and beaten him for two hours with a broomstick. For most of his childhood, Mohammed would be in and out of group homes, where he could be protected from his brother. Abdelkader beat his older sisters if they smoked or stayed out late; he beat his mother, too, and she took to locking herself in a bedroom when he was home.

Mohammed attacked his mother as well. In 2002, when he was 13, his middle school principal wrote to a judge that Aziri had come to her with “several marks on her face and numerous bite marks on her arms.” Mohammed was apparently no longer sleeping, and spent his evenings terrorizing her. “He’s crazy,” his mother told the principal. Mohammed was placed in another group home.

That same year, after punching a social worker in the face—the woman had accompanied Mohammed and Aziri to a court date, and he grew angry after his mother reacted unfavorably to the prospect of having him back at home—he was evaluatedby a court-mandated psychologist. “Mohammed Merah’s discourse shows no sense of guilt,” the psychologist wrote. “He does not imagine the repercussions of his acts on the person he assaults because he places himself in a position of victimhood.” He had told her, “For adults it’s ‘violence,’ but for me it’s self-defense.” He was frequently sad, he reported—social workers indeed often found him crying, even as a teenager—and he sometimes thought of suicide. (In 2008, while in prison, he tried to hang himself.) The psychologist reported that his mother showed no understanding of her son’s behaviors, no notion of the forces that might be driving them. She was unwilling, probably unable, to interrogate the norms by which she and her family lived. Aziri showed “little capacity for mental elaboration,” the psychologist wrote, and “little self-awareness.” The events of her life were so unremittingly grave as to fail to register in her as serious at all.

In court, she lied about them. Her relationship with her ex-husband had been “a normal relationship,” she said, and she denied that he had ever beaten her. The president asked if Abdelkader had been violent when he was younger. “Abdelkader? Abdelkader normal,” she said.

“You’re sure?” the president asked.

“Sure,” she replied. The president read from a social worker’sreport, describing Abdelkader’s violence. “No, no, no,” Aziri said. She was asked if, in light of the violence, her family was perhaps not entirely normal. “Of course it’s normal,” she insisted. It was pointed out to her that her sons had committed a great number of violent acts, including murder. “There is no problem in the Merah family,” she said. “We’re not animals!” She denied having spoken to the police after Abdelkader tied Mohammed to the bed. The president read aloud from her statement from the time; she denied having given it.

The president turned to another line of questioning. Mohammed had lured his first victim to the site of his murder by claiming to want to buy his motorcycle, which the man, Imad Ibn-Ziaten, had put up for sale on the internet. (In his listing, Ibn-Ziaten had identified himself as a soldier.) Several days before the killing, shortly after eleven in the evening, someone had connected to the online classified from within Aziri’s apartment. Investigators suspected that it was Abdelkader who viewed the advertisement that night, and if this could be proved, his complicity in his brother’s killings was patent.

From the start and throughout the five years of the investigation, Aziri had maintained that Mohammed did not come to her apartment that night. She acknowledged that Abdelkader had been present earlier in the evening, but said he had left several hours before the connections were made. And yet Abdelkader’s cell phone pinged a cell tower near his mother’s apartment at the time of the connections, and the alibi he initially provided for his whereabouts that night—he claimed to have been at a party—proved false.

In court, Aziri denied that either of her sons had come to her apartment that night. “I was alone,” she said. “There was no one there!” Mohammed must have made the connections from outside her apartment, she said, by Wi-Fi. She was reminded that investigators had found that Ibn-Ziaten’s ad had not been accessed over Wi-Fi but via the hardline internet connection inside her apartment. “For me, what your technicians said isn’t true,” she declared.

To watch Aziri flail and fight and simply refuse to be honest was to resign oneself to the conclusion that she, and whatever knowledge she had of the crimes, was beyond reach.

It was incomprehensible, given the ease with untruth that she’d already demonstrated, and the lack of legal consequences, that she did not simply lie and say that she now remembered that Mohammed had come to her apartment that night, that it must have been him and not Abdelkader. This would have made clear that, if the court and plaintiffs and country were to be deprived of the information she possessed, it was out of a maddening but comprehensible desire to free her surviving son from prison. But reason seemed to have no purchase on her; her obstinacy was pointless. To watch her flail and fight and simply refuse was to resign oneself to theconclusion that she, and whatever knowledge she had of the crimes, was beyond reach.

A lawyer for the Ibn-Ziaten family stood to make his own attempt.

“Madame, this family wants to know the truth,” he said.

“That’s normal,” Aziri said, almost sympathetically.

The lawyer explained once again that whoever made the connections was necessarily inside her apartment.

“Mohammed took the codes and connected from outside,” Aziri said through the translator.

“That’s not possible!” the lawyer yelled. “There was someone at your apartment! The Ibn-Ziaten family has the right to know!”

“No one! There was no one at my apartment!” she shouted, switching now into rapid French. “Abdelkader isn’t there! Why are you speaking to me like this?! Me, too, I can speak to you like this!” Abdelkader reached a hand through an opening in the glass box and motioned to his mother to calm down.

“The families have the right to know the truth!” the lawyer yelled. “They’ve been waiting for it for five years—five years!”

Abdelkader’s lawyer, Éric Dupond-Moretti, stood and began to bellow across the aisle of the court. “What has she done?” he demanded. “What are you accusing this woman of?” The courtroom went nearly silent. “Of lying? And so what? She’s the mother of the accused, and she’s the mother of a dead man!”

The courtroom erupted. From the rear, a young man, IbnZiaten’s younger brother, screamed at Dupond-Moretti. “You’re not ashamed?! Shut up! Shut up!” he shouted through tears. “You’re a murderer! You’re mean! You’re shit!” He stumbled from the courtroom.

Dupond-Moretti had been wildly indecorous, and his words evidently set off the outpouring of the man’s anguish, but I do not think they were its source. The man’s deepest grievance, of course, was with his brother’s killer or killers, and the mother who was evidently shielding them. But I suspect it was also with the contention, which had been peddled to him since the days after the murders and throughout the five years that followed, that Mohammed’s radical evil had been fomented and then abetted by Abdelkader, and that a trial would prove it, and that it was thus possible to grant the victims the tidy moral resolution they deserved. What the events of the trial instead demonstrated was the cruel inadequacy of this contention, the naïveté of this logic. The most terrible discovery for anyone who watched the trial closely and was willing to plumb his own sense of disorientation was that the Merah family inhabited a corner of the world where logic of this sort simply did not hold.

Throughout the trial, I often shared a bench in the salle des assises with an anthropologist named Ariel Planeix. Planeix had been recruited by the French Ministry of Justice to produce an internal study on the lives of several dozen “radicalized” minors, some of whom had been before the courts, and others whose cases were handled by social workers. The upheaval and trauma of the Merahs’ lives were essentially average among the cases he’d seen, he said. He viewed Mohammed as a template for the generation of jihadists that has emerged since his killings. “He’s the new face of a sort of reactive violence,” he told me, violence that is politicized but that is hardly rooted in politics. The minors Planeix studied had all been abused, abandoned, or raped, and sometimes all three; if they remained in contact with their families, their families systematically denied the existence of any such problems. Their childhoods, like the Merahs’, were an almost absurd cumulation of horrors. A growing body of research suggests that, among this new generation of jihadis, this is indeed the norm. This is not to suggest that jihadism is merely a social problem, but rather that “radicalization” is much more than a matter of ideology and its transmission.

This ought to be a source of reassurance. Radicalization is not the vast crisis it has often been made out to be in the West, and certainly not an existential threat; it seems to operate upon a very particular population, and that population is small, damaged, and profoundly marginal. It is the great luck of the Salafi-jihadis that that their Islamic mythology should hold appeal for these men at the terrible margins; it is their great luck, too, that European societies should be so confounded by these men, torn between their loathing for them and a buried guilt for the outrages to which they, in their marginal lives, are exposed. Beneath the anger and horror at every jihadist attack in Europe is, like a shameful, postcolonial secret, an unsung note of self-reproach. Shame, like fear, is only very rarely a spur to sober evaluation of the problems at hand. But it is easier to overcome.

Abdelkader’s lawyers argued his right to think and believe as he saw fit. They were no more interested in an examination of how or why he’d chosen his particular path than was the prosecution. The trial served, then, as much as anything, to perpetuate Abdelkader’s own myth about himself, as a man defined by his extreme convictions, a sort of empty vessel filled, by divine providence, with jihadist Islam. This was a myth that was almost entirely palatable to his accusers, absolving them as it did of the uncomfortable responsibility of looking closer. The myth of pure evil flattered all. The court ostensibly scrutinized Abdelkader, his family, his neighborhood; but it seemed to see only what it wished, or what Abdelkader wished, in each of them.

“Do you have anything to add to your defense?” the president asked Abdelkader on the final morning of the trial, turning to the glass box.

“Yes, Monsieur le Président,” Abdelkader said blandly. He stood to speak. “I said it before and I’ll say it again: I have nothing to do with the killings committed by my brother.” He had finished his statement.

In the evening, the president read out the judges’ verdict, accompanied by an explication of the logic by which they had concluded that Abdelkader had not been shown to be his brother’s accomplice, but that he had participated in “a terrorist grouping or agreement” with him nonetheless. The Merahs’ association aimed to commit killings, the judges wrote, and this intent was revealed “precisely” by the killings Mohammed committed. Abdelkader was sentenced to 20 years.

There can be little doubt that Abdelkader Merah is a very dangerous man, and I suspect that everyone in the courtroom was relieved to see him convicted. But it was a glorious day for no one. Abdelkader sat unmoved in the glass box. In the end it was the prosecution itself that chose to appeal, finding the partial conviction insufficient.