“Now I don’t like killing innocent people, but in this case it is allowed,” surviving Boston Marathon bomber Dzhokhar Tsarnaev wrote days after he and his brother Tamerlan perpetrated the April 2013 massacre. Since then, Tsarnaev has issued no statement of regret or remorse. He has been flawlessly loyal to his cause, which resulted in the deliberate maimings and murders for which a jury in Boston sentenced him to death last week.Yet much of the coverage of the brothers portrays them as tentative, uncommitted characters. Their motives for the bombing have been treated as a troubling mystery, when there is in fact a very long record of statements and actions that leaves very little room for interpretation and doubt. Our desire to muddy these rather clear waters therefore says a lot more about us than it does about the Tsarnaev brothers.Most reporting about Dzhokhar Tsarnaev describes what we would like him to be—a drifting, desperate young man who did something absurd and horrible—rather than the way he actually sees himself, which is as a soldier in a just war. “Is it conceivable that the Tsarnaev brothers were not the marathon bombers but, once they knew they were the suspects, they decided to run?” Masha Gessen asks in her new book The Brothers: The Road to an American Tragedy. “The answer would have to be, Yes, it is conceivable.” As of January 2015, when Dzhokhar Tsarnaev’s trial began, Gessen writes, there was “nothing that directly linked the Tsarnaev brothers to the bombing or explained its mechanics or the brothers’ motivation.”***Masha Gessen now says she has no doubt that the brothers committed the bombing. But the case’s unanswered questions worry her, most of all this one: Did the FBI employ Tamerlan Tsarnaev, the apparent ringleader of a terror plot that killed three people and wounded hundreds? When I interviewed Gessen last month at a cozy bohemian café in her West Harlem neighborhood, she insisted to me that “the FBI had a relationship with Tamerlan. They interviewed him three times over several months. I’m not saying that they were in bed together necessarily, but it raises the possibility.”Gessen abhors the brothers’ murderous actions. But she also identifies with the Tsarnaev family. Like them, she is a displaced person, transplanted from Russia to America when she was a teenager. They are Chechen, she is Jewish—both persecuted minorities during the Soviet era. She is also a gay parent who left Russia for New York several years ago because she feared for the safety of her children. Putin’s Russia threatens gays as it does Chechens: Both are seen as foreign elements, dangerously anti-Russian.Gessen has a strong feeling for the brothers’ cultural roots. She devotes some of her most poignant pages in The Brothers to the tragic history of the Chechen people. In 1944 Stalin ordered the Chechens to be transferred from Chechnya to Kyrgyzstan, and half of them died in the process. A half-century later came two wars between Russia and Chechnya, the second waged by Putin in the 2000s. Russia laid waste to Grozny, Chechnya’s capital city. Gessen thinks Putin himself ordered the 1999 apartment block bombings in Moscow that killed hundreds of Russian citizens so he could blame the explosions on Chechen rebels, start a war, and rally Russians to his leadership.The brothers’ parents come from Kyrgyzstan and Dagestan, not Chechnya. Their family saga is well known by now: Most of what Gessen reports is familiar from earlier reports by the Boston Globe and Rolling Stone. But it’s the nuances that count, and Gessen tells the story with great mastery. She traveled to Dagestan to do her research, and her descriptions of the region’s untamed edge-of-the-world atmosphere alone make her book worth reading.Gessen writes beautifully about the courtship of Zubeidat and Anzor, the brothers’ parents, who met in Kyrgyzstan. Anzor and Zubeidat were teenage rebels, bucking convention and insisting on their love. Zubeidat is not a Chechen but an Avar, from another Muslim ethnic group, and Anzor had to overcome his parents’ fierce opposition in order to marry a non-Chechen. Zubeidat dressed with crazy youthful flair and sported a shaggy Pat Benatar-style hair-do. When she and Anzor moved to Dagestan they were still deeply in love. But after the couple came to America in 2002, Anzor became angry and unstable. His psychiatrist has testified that Anzor had psychotic tendencies. Neighbors began to fear his furious outbursts.To make money, Anzor fixed cars in his driveway. Zubeidat worked in a salon giving facials but then suddenly became devoted to Islam and started to wear a hijab. She shared with her sons a taste for conspiracy theory and, the Globe reported, told one of her salon clients that Sept. 11 was “purposely created by the American government to make America hate Muslims.”Since their days at Rindge and Latin, Cambridge’s hip, multicultural high school, Zubeidat’s sons Tamerlan and Jahar—Dzhokhar’s nickname—had been looking for a cause. Jahar went to UMass-Dartmouth and started dealing pot. “He had the best bud on campus,” a friend marveled. Tamerlan boxed, skipped school, and wore flashy clothes: silver boots, disco shirts open to the navel, and worked as a pizza- and pot-delivery man. Then, something changed. Influenced by his mother, he became a devout Muslim, though he still smoked pot. By 24 he had married a woman named Karima (Katherine) Russell, a convert to Islam, and with her was raising their infant daughter in his parents’ house, while subjecting his young family to violent outbursts.Nobody seems to have disapproved of the way Tamerlan and his mother embraced Islam, except for her husband Anzor and his brother Ruslan, both adamant secularists. Yet Gessen seems eager to detect anti-Muslim fervor in the air. “They”—meaning us—“waged war on the Muslims. It was always the Muslims,” she writes. Gessen speaks of America’s “witch hunts” against Muslims, but neither the Tsarnaevs nor anyone they knew was a victim of anti-Muslim persecution in the account she offers. Gessen is profoundly right to oppose anti-Muslim prejudice, but she fails to uncover any evidence at all of such prejudice during the Tsarnaevs’ time in the United States.***Americans have always rejected the false notion that all Muslims are to blame for terrorism. But we know—how could we not?—that many terrorists are Islamist radicals. The American public, Gessen complains, assumed that Muslims had committed the Boston bombing. But Muslims, namely the Tsarnaev brothers, acting in the name of Islam, did commit the Boston bombing. She doesn’t mention that the news media at first supposed that the massacre must have been the work of native right-wing terrorists, since it occurred on Patriot Day and Tax Day.Gessen slights the role that radical Islamist beliefs played in the Boston bombing. She barely mentions Tamerlan’s enthusiastic embrace of jihadist propaganda, giving the subject only a page and a half in a 273-page book. Nowhere does she refer to Tamerlan’s Islamist rants, the ferocious attacks on religious tolerance that he delivered at the local mosque and elsewhere in Cambridge. “Ideas are important,” Gessen admitted when I asked her whether Islamist fervor was behind the Boston bombings. But in The Brothers she soft-pedals ideas, instead focusing on Tamerlan’s and Jahar’s feelings of alienation in a foreign land.During the sentencing phase of Jahar’s trial, new evidence about Tamerlan’s violent radicalism came to light. Tamerlan’s second cousin Magomed Kartashov said that “he came to Russia [to Dagestan, in 2012] thinking he would find jihad in the streets.” Tamerlan, Kartashov said, had become a devotee of the Yemeni-American radical cleric Anwar al-Awlaki. Jurors saw a photo of Tamerlan waving a pistol, posing as an al-Qaida-style warrior in Gulf Arab garb, with a jihadist flag behind him.The brothers set off bombs at the marathon because America, they were convinced, was out to kill innocent Muslims, and something had to be done. The story is a sadly typical one, though Gessen treats it as a puzzle. “What is truly lacking” from her book, Gessen confesses in its final pages, “is a clear and accessible explanation for how two young men who appear to be very much like hundreds of thousands of other young men came to cause damage in the center of their own city.”Gessen may be perplexed, but there is no big mystery here. Many millions of Muslims around the world, prompted by extremist ideology and messaging, are convinced that America—and, more so, Israel—have set out to deliberately massacre as many Muslims as they can. If you believe this, then you must also believe that sooner or later someone must strike back. At the very least, you will have mixed feelings about the actions of terrorists: Their hearts are in the right place, you might feel, even if you find their deeds repugnant. Surrounded by reports about the West’s genocide against Muslims, you might even overcome your own moral disapproval of murder and become a killer for the sake of your people. If anything, it is strange that there aren’t more terrorists like the Tsarnaev brothers.Jahar Tsarnaev’s last words before his capture testify to his fervent belief that America wants to slaughter Muslims. As he cowered in a boat in Watertown, wounded and hiding from police, he wrote on the boat’s wall that “the US Government is killing our innocent civilians” and “I can’t stand to see such evil go unpunished, we Muslims are one body, you hurt one you hurt us all.” “Stop killing our innocent people and we will stop,” Tsarnaev scrawled. This, which Gessen calls Jahar’s “non-confession confession,” is as clear and accessible an explanation of the Boston marathon bombing as one could ask for. The Tsarnaev family’s aching sense of displacement, which Gessen explores so sensitively, is less significant in understanding their story than the way that an average Muslim’s displacement and alienation can, in a worst-case scenario, find an easy outlet in violence.Yet Gessen is much less concerned with Islamist ideas than she is with the FBI. The bureau bungled the aftermath of the bombing, taking far too long to identify and locate the Tsarnaev brothers. Gessen seems to think that the bungling was deliberate, and has run into some trouble for her willingness to entertain conspiracy theories that seem more appropriate to Vladimir Putin’s dystopian New Russia than to Barack Obama’s America. Former Secretary of Homeland Security Janet Napolitano, in her New York Times review of The Brothers, lambasted Gessen for advancing the “laughable” theory that the FBI deliberately delayed their pursuit of the brothers after the bombing.“The explanation that best fits the facts is a cover-up,” Gessen writes. This is the sentence that got Napolitano’s attention: The FBI “needed to ensure that no other law enforcement got to Tamerlan Tsarnaev before the FBI had captured—or killed—him.” The FBI may have wanted Tamerlan dead, Gessen surmises, so that he wouldn’t reveal that he had worked for the agency. He might have been an informant who went rogue, a serious source of embarrassment for the FBI! Yet there is simply no evidence that Tamerlan was ever an FBI informant, let alone that the FBI’s investigative failures in the case were the result of a far-reaching conspiracy.***There are plenty of other loose ends in the Tsarnaev case, and Gessen is right to want some answers. Hundreds of documents from Jahar’s trial have been sealed. A brutal triple murder in 2011 in nearby Waltham that Tamerlan might have had a hand in was, as Gessen notes, “never solved or, really, investigated.” A key witness named Dolakov, who went to the gym with Tamerlan days before the bombing, is nowhere to be found. Finally, no one knows where or how the brothers’ pressure-cooker bombs were constructed, unless the information is in one of the sealed transcripts. Gessen told me that it might have taken “hundreds of thousands of fireworks” to make the bombs, which were assembled while Jahar was going to college in Dartmouth and Tamerlan was taking care of his infant girl in Cambridge. Maybe the brothers stayed up all night for months taking apart fireworks, or maybe they had help. Many have thought that Tamerlan’s wife, who did not testify in court, might have been in on the murderous project. Or maybe her estimate that it would take “hundreds of thousands” of fireworks is off by a factor of 10, or 100. Whatever the case, the simple facts of her story appear to be the hardest ones for her to assimilate.Gessen’s treatment of the Tsarnaevs is in the end oddly reticent. Perhaps she is afraid that her sympathy for her characters might fail if she were to get to know them too fully. The tight relation between the brothers, the birth of their plot, the making ready of the bombs and the lethal act itself—Gessen skips over all these crucial details. Such empty spaces don’t usually appear in her work: Often she speculates searchingly about what her real-life characters might have been thinking and feeling. This is especially true in Ester and Ruzsya, her book about her two grandmothers who survived Hitler and Stalin and who both died this past year—when I saw Gessen she had just come back from Ruzsya’s funeral in Russia. It is probably the best of Gessen’s books, because it is the one closest to her. While Gessen’s love for the two women springs from every page, just as impressive is her subtle reimagining of their husbands’ lives: Both men died in the war, one in the Bialystok ghetto and the other on Stalin’s eastern front.During our interview Gessen backed away from her notion of an FBI plot. She admits in The Brothers that FBI incompetence might explain the mishandled Tsarnaev manhunt. She described herself to me as a follower of the “chaos and idiocy theory of everything” and noted that she herself has been a victim of conspiracy theory. Because Vladimir Putin once called her out of the blue, summoning her to his office for a rather chilling one-on-one talk—an episode she describes in her book on Putin, Man Without a Face—“some people I used to consider friends,” she says, think she is an agent of the FSB, the Russian secret police.Putinism insists that Russia cannot remain the eternal victim of foreign powers, and so the nation needs to rise up, to flex its proud muscles. The Islamist radicalism that ensnared the Tsarnaev brothers works the same way: A victim mentality leads to grandiose self-assertion and, finally, the need to do something to prove manhood and reach heroic meaning. One hopes that Gessen, who is now writing a book about “the current Russian totalitarianism,” will also consider this other totalitarianism, which poses just as volatile a threat to the world. She is such an acute reporter, and such a rewarding thinker about the grim horizons of 21st-century politics, that we need her voice on more than one front.***Like this article? Sign up for our Daily Digest to get Tablet Magazine’s new content in your inbox each morning.David Mikics is the author, most recently, of Bellow’s People: How Saul Bellow Made Life Into Art. He lives in Brooklyn and Houston, where he is John and Rebecca Moores Professor of English at the University of Houston.