In the 1860s, when the architect Frederick Law Olmstead arrived in Crow Hill, he found a wasteland of balding farms and graying shale, pimpled by shantytowns and pools of pig excrement. The squalor alarmed Olmstead, and together with his partner, Calvert Vaux, he obtained a commission from the city to design Eastern Parkway, a wide, tree-lined boulevard that eventually connected the brownstones of Park Slope to the tenements of Brownsville and brought a semblance of modernity to the neighborhoods in between.

Jewish émigrés from Russia and Europe were among the first to settle the hills surrounding this new thoroughfare. For the most part wealthy, they built spacious brick mansions and beveled-limestone row houses on the cross streets off Kingston Avenue, which runs north to Bedford-Stuyvesant and south to Flatbush. Crow Hill was soon rechristened Crown Heights, an appropriately regal name for a neighborhood of immigrant strivers. In his memoir A Walker in the City, Alfred Kazin, who was raised in Brownsville, dubbed the residents of 1930s Crown Heights “alrightniks” — middle-class Jews who had managed to do “all right” in the New World.

The history of New York City includes hundreds of such small-scale real estate sagas — colonizations and recolonizations, incursions and retreats, the exodus and return. Inevitably then, in the years after World War II, the alrightniks began to lose their grip on the neighborhood. The enclave might have remained intact — if diminished — had it not been for the passage, in 1965, of the Hart-Celler Immigration and Nationality Act, which eliminated nationality quotas and introduced a wave of immigration from Asia, Africa, and the Caribbean.

In Crown Heights, the bulk of the new arrivals were West Indian. “Every jack-man buying a swell house in ditchy Crown Heights,” Paule Marshall wrote in her novel Brown Girl, Brownstones, which documents Caribbean immigrant life in Brooklyn. Soon, roti shops and Creole seafood restaurants had sprouted up alongside the kosher delis; talk in the park turned from baseball to cricket. Crown Heights became the seat of the Brooklyn West Indian Carnival, the largest ethnic festival in New York City. The alrightniks took their cue. Many fled for upper Manhattan; others for bedroom communities in New Jersey and Connecticut.

And yet the Jewish presence in the neighborhood by no means vanished. Many apartment complexes and synagogues remained in the hands of the Lubavitchers, an ultra-orthodox Jewish sect. Like all Hasidim — “pious ones” in Hebrew — Lubavitchers adhere strictly to traditional Jewish law. Their lives are circumscribed by prayer, study, familial obligation, and a deep commitment to their Rebbe, or grand rabbi, who is considered closer to God than are other mortal men. In 1969, the seventh Lubavitcher Rebbe, Menachem Mendel Schneerson, commanded his Hasidim to fight for their foothold in Crown Heights, quoting from Deuteronomy: “Do what is right and good in the sight of the Lord, so that all may go well with you and that you may be able to possess the good land that the Lord your God promised on oath to your fathers, and that all your enemies may be driven out before you.”

Lubavitchers could no longer dominate all of Crown Heights — they were vastly outnumbered by West Indians and African Americans — but they could adopt a policy of demographic consolidation. Between 1970 and the 1990s, Lubavitch leadership worked to control the sixteen-square-block area directly adjacent to Kingston Avenue, the high street of the Hasidic settlement.

According to one survey taken in 1987, more than 60 percent of black homeowners in Crown Heights had been approached with unsolicited offers from potential buyers, most of them Hasids. Community leaders complained that the Lubavitchers received an iniquitous amount of government funding (a charge refuted by several contemporary reports, including an analysis published in the New York Times) and preferential treatment from the fire and police departments and municipal services. “Sometimes I feel like we are living in an apartheid state where a tiny minority is controlling our state,” an African-American woman complained to theTimes in 1987. This resentment culminated in the race riots of 1991, which pitted the Lubavitchers against the black community and left several people dead.

Still, as anthropologist Henry Gold-schmicit has noted, even after the riots wound down, many in Crown Heights were split on whether the political clout of the Hasidim represented “an attack on their neighborhood’s black majority, a model of community empowerment to emulate, or both.” The Lubavitchers had built a world within a world, and it was a world to respect, even if grudgingly.

A Hasid could shop for kosher food, purchase a fedora and black suit, pray at shul, and visit his Rebbe, without walking more than half a mile. They had diners, museums, bookstores, yeshivas, and hotels for the thousands of pilgrims who came to Crown Heights to visit Schneerson’s court. A volunteer Jewish ambulance corps, Hatzalach, was pressed into service. There was a beis din— a Jewish court — to adjudicate community matters, including divorces and monetary disputes.

In 1992, Schneerson suffered a stroke, and he died two years later in his Crown Heights home. He was ninety-two. With previous successions, a new Rebbe was appointed quickly to avoid infighting or even the disintegration of an entire movement. But a new Rebbe has never been named. The reason is primarily eschatological: even before Schneerson’s death, a sizable segment of the Lubavitch community had come to believe that their Rebbe was the Messiah.

Technically, all Lubavitchers are messianists, in that they believe that a messianic age is imminent and that it can be ushered in with piety, prayer, and the fulfillment of the 613mitzvot, or commandments, identified in Holy Scripture. But after Schneerson’s death the Lubavitch community broke along messianist lines. The Meshicists, as they are known in Crown Heights, announced that it was their duty to spread the word of the Messiah’s arrival. (Schneerson’s physical death is not necessarily a hindrance to his messianic duties: the soul of aTzadik, a righteous man, is said to remain close to his body for years.) Other Lubavitchers did not necessarily deny that Schneerson could be the Messiah; they just worried that if the Meshicists came to dominate the Lubavitch movement, it might scare away prospective converts.

The messianist debate, combined with the lack of a Rebbe, has wreaked havoc among the Lubavitch. The word one hears most often these days on Kingston Avenue is “vacuum.” There is a vacuum of leadership at the main Lubavitch shul on 770 Eastern Parkway, and a vacuum of leadership on the Jewish Community Council, which helps run the neighborhood. Although they are loath to admit it publicly, many Lubavitchers believe that the kingdom built by their late Rebbe is in danger of falling apart.

One manifestation of this turmoil is the feud between the Shmira and the Shomrim, two Lubavitch anti-crime patrols established locally to help protect “the good land” of Jewish Crown Heights, and perhaps even drive out a few enemies. The Hasidic community has a long history of civilian anticrime efforts. There are Shomrim almost every where large concentrations of Hasidim are found: in the Williamsburg neighborhood of Brooklyn, in Stamford Hill in London, in Melbourne. The Shomrim (Hebrew for “guards”) functions a little like an auxiliary police force. Its members — all volunteers — fix tires, help direct traffic, and escort elderly residents to and from the bus stop. They are also routinely involved in more athletic endeavors, like chasing down purse snatchers or breaking up street fights. They do not have the power to make arrests, but they can hold a suspect until the real police arrive.

The Shomrim see themselves as natural successors to groups like the Bielski partisans, a Jewish militia that fought the Nazis in German-occupied Poland. In most cases, they are a helpful presence. In Williamsburg and Flatbush the Shomrim are often credited by the police with helping to reduce incidents of petty crime. This was once the case in Crown Heights too. No longer.

The problems began in 1999, when the Crown Heights Shomrim split in two. The details are disputed, but one faction, which has retained the name Shomrim, claimed that the other faction, which patrols as the Shmira, had been a party to a bank robbery. The Shmira, meanwhile, sought to cast the robbery as a failed putsch on the part of the Shomrim. The groups now maintain dispatch centers on opposite sides of Crown Heights. In Schneerson’s day, the leaders of both patrols would have been yanked into an audience with the Rebbe and commanded to make nice. Because there is no longer any central Lubavitch authority, the feud has grown.

One damp day in November 2009, I took the subway to the Brooklyn Supreme Courthouse, where six members of the Crown Heights Shomrim were on trial for gang assault. Proceedings were scheduled to commence at 10:00 A.M., but by 10:30 the judge had not yet appeared, and I found a seat at the back of the gallery, next to a young Hasidic attorney named Isaac Tamir. Around us, the Lubavitchers in attendance chattered anxiously — the men worrying the fringes of their ritual undergarments and the women clutching Gucci handbags and working the touch-screens of their BlackBerries.

“You know, I’m always looking for reporters to cover my cases,” Tamir whispered to me. “Maybe we can work something out.” He was wearing a stained tie knotted loosely around his neck; his suit looked a size too big. He said he’d once worked as an assistant district attorney in Brooklyn, and I asked him whether he thought the jury would understand the complexities of the Shomrim case.

“They don’t have to understand everything,” he said. “They just have to understand what the whole thing is really about.”

“What is it really about?”

“The feud, of course.” He opened his blue eyes wide. I had shown my ignorance. “Without the feud, there wouldn’t have been the brawl. Without the feud, the Shomrim would never have been charged. The feud is the reason six Jewish boys are on trial.”

Two years earlier, Shomrim dispatch had received a call about a disturbance at the yeshiva dormitory at 749 Eastern Parkway. Witnesses later reported seeing six Shomrim punch, strangle, and kick their way through a crowd of rabbinical students. The Shomrim claimed to have been ambushed. A video recorded by one of the students seemed to back this up: on the tape, the Shomrim are trapped, hemmed in on all sides by a mass of black hats and coats.

Had it not been for the efforts of a Lubavitch lawyer named Levi Huebner, the police probably would have been content to issue a few desk-appearance tickets for misdemeanor assault. But Huebner, who is himself a member of the Crown Heights Shmira, had relentlessly pushed the city to go after the Shomrim; he was also pursuing a multimillion-dollar lawsuit on behalf of the rabbinical students. A source at the D.A.’s office told me that Huebner was providing essential aid to the prosecution — translating for the victims, producing witnesses, identifying Shomrim. Without Huebner, there would be no trial. I asked Tamir whether people were angry with Huebner. “Why?” he said. I suggested that, historically, internal Jewish disputes had been settled by Jewish courts. He shrugged. “It’s not like that anymore. People go to secular courts all the time.”

That was essentially true — Lubavitchers, like all Americans, have become ever more litigious in recent years — but I later learned that many people were furious at Huebner. They believed that because he is aligned with the messianist camp in Crown Heights, Huebner had both religious and political reasons to go after the Shomrim, a group composed mostly of moderate, non-messianist Lubavitchers.

“What will happen to the Shomrim?” I asked Tamir. He didn’t know. “I have to go visit a client.” He presseda business card emblazoned with his head shot into my hand. “Call me,” he said.

Among the witnesses that day was Yaakov Shatz, a young rabbinical student who bore a striking resemblance to a hobbit. He had small, bright eyes, a tangled mess of brown hair, and rounded features, and couldn’t have been much more than five and a half feet tall. Shatz was an alleged victim in the assault, and on cross-examination, one of the six defense attorneys, Israel Fried, attempted to get him to admit to the ideological divide between the rabbinical students and the Shomrim.

The majority of the residents at 749, as it is known locally, are Israeli Hasids, who come to Crown Heights to earn their rabbinical ordinations. For two years, these bochurim (“boys” in Hebrew) maintain a cloistered existence, shuttling between the dormitory and the basementshul on the other side of Eastern Parkway. They are considered especially zealous among Lubavitchers. The bochurim wear yellow pins emblazoned with the motto of the Meshicist movement — LONG LIVE OUR MASTER, OUR TEACHER, AND OUR RABBI, KING MESSIAH, FOR EVER AND EVER — and often dance through the main Lubavitch shul waving a big yellow flag. “The Meshicist bochurim — they are not like us,” a Lubavitch acquaintance once told me. “They are more like Arabs than Jews. Like the Taliban. They will destroy us.”

If Fried could get Shatz to discuss community politics on the stand, he could show that the Shomrim may have been ambushed because of their religious beliefs. Shatz grunted and smirked and did his best not to answer questions directly. The six defendants sat at the front of the courtroom, scowling in unison at Shatz. “Get on with it,” someone whispered from the gallery, and the Shomrim guffawed. The pace of the testimony was glacial. Because Shatz spoke only Yiddish and Hebrew, an octogenarian translator had been summoned, but the translator employed a decidedly antique English — he insisted on referring to the students as “lads” — and Fried again and again had to ask for clarifications. At noon, Shatz finally stepped down, and the judge, the Honorable Albert Tomei, called a two-hour recess for lunch.

I followed the crowd through the double doors and out into the waiting room, where a group of Hasidim were working through their afternoon prayers. The davening was efficient, mechanical: knees bent, precise rotations of the legs, arms, feet; then the slow, heavy thrum of the words. In the corner of the room, one of the defendants, Benjamin Lifshitz, was standing with his parents and his attorney. I knew Lifshitz casually but had not yet met his family, so I walked over and introduced myself. He was wearing a blue pin-striped suit, a pair of expensive glasses, and a felt yarmulke. He put his hand on my back. I shook hands with his father, Yossi.

“What did you think?” Yossi asked.

Oh, you know …”

“You didn’t find Shatz convincing?”

“Let me tell you something,” said Yossi, who is tall and shaped like a large matryoshka doll. “I go to China sometimes for business and the girls there are taught to say, ‘What would you like for breakfast?’ But they can’t go beyond that phrase. That’s because they’ve been taught to say their lines but not to understand what they’re saying. Shatz has the same problem. There’s no way the jury is going to buy it.”

As it turned out, Yossi Lifshitz was right. In November, Tomei dismissed the gang-assault charges, and on December 9, after weeks of testimony, the jury found five of the six Shomrim not guilty of all charges. Only Gedalia “Gadi” Hershkop, a burly, black-haired giant, and the co-coordinator of the Crown Heights Shomrim, was convicted, of misdemeanor assault.

Levi Huebner lives with his family in an apartment on a heavily rutted side street just off New York Avenue. A couple of months after the trial, Huebner invited me to spend Shabbos (Sabbath) eve with his wife and several of his children. This Shabbos was of special significance for the women of Crown Heights — it was the anniversary of the death of the Rebbe’s beloved wife, Chaya Schneerson — and driving down Eastern Parkway, I saw gaggles of young Lubavitch women singing and skipping hand in hand through the purple dusk.

Huebner met me at the door of his apartment. His wiry hair was long and unkempt, and when I leaned in to shake his hand I smelled the mulchy tang of sweat. The women were in the living room lighting the Shabbos candles, and Huebner showed me to a long leather couch and presented me with a glass of whiskey. The drink was strong; after a few sips, I, too, was sweating. Huebner watched me with interest, separating the strands of his tangled silver beard with his non-drinking hand. He began to recite his biography. Before he got into the lawyering business, he had dealt in precious gems. He changed professions, he said, because there was no longer any cash to be made in diamonds. He was raised in Berkeley, California, by his stepfather, an artist and a professor at the University of California, and his mother, a poet. Several of his childhood friends became drug addicts, and he indicated that he had himself dabbled as a younger man. (“LSD is a nasty drug,” he told me.) He often visited Oakland — “the Harlem of Northern California” — and had taken to carrying a loaded pistol in his pocket. I asked him whether he’d had occasion to use it. “I don’t talk about that,” he said.

Huebner and I were set to leave for temple at 5:30 P.M. with his youngest son, Josef. Before we headed out into the cold, Huebner checked the weight of my jacket — to make sure I wouldn’t freeze to death — and finding the material wanting, asked me if I wanted to borrow a scarf. Six teenage girls milled around the living room, all friends of Huebner’s daughter. Later that night, after services, I would watch the girls work their way through two six-packs of Smirnoff Ice; one got so drunk she fell off her chair and landed on the ground with a tinny crash, her dress twisting up toward her waist.

We left for 770 Eastern Parkway — headquarters of the international Lubavitcher movement — in two waves: first the women, who would be confined to the glassed-off enclosure on the second floor of the shul, and then the men. On the walk over, I asked Huebner what would happen if he ran into Lifshitz and the other Shomrim boys from the trial. “I’d ignore them if it happened,” he said, “but they wouldn’t dare show up there.” Although 770 remains an important location for the entire Lubavitch community, the first floor — the official shul area, where the Rebbe once addressed his Hasidim — now belongs mostly to local messianists and the Israeli bochurim. The Shomrim would be more likely to worship at other, smaller shuls scattered around the outskirts of Crown Heights.

It quickly became apparent that I was something of a trophy to Huebner. “This is Matthew Shaer from Boston, Massachusetts,” Huebner said to each person we met on the street, my cue to nod, shake hands, and say, “Good Shabbos.” Crossing President Street, we ran into Rabbi Krinsky, the leader of the anti-messianist camp. He looked Huebner up and down and nodded, and then went quietly on his way.

Unlike a traditional service, Friday night services at 770 are a kind of do-it-yourself exercise. Hundreds of Lubavitchers flood onto the main floor and jostle elbow to elbow for a place todaven. I followed Huebner through the crowd, watching the faces of the other Hasidim as we approached. Most kept their eyes on their books. After the services had concluded, Huebner introduced me to a group of Shmira who had set themselves up near the door of the shul. Yanky Prager, one of the leaders of the patrol, was there with his sons, and he greeted me warmly. Two younger members were less open; one pointedly asked me what I was looking for.

“Just here for a visit,” I said.

“I’ll bet,” he sneered.

During the ceremony, both messianists and anti-messianists mingled and prayed together, but once the davening ended, the floor was flooded with Israeli bochurim, who often spend hours singing, occasionally in the direction of the chair where the Rebbe once sat. Several older Lubavitchers cleared the area at the west end of the hall, and the bochurim began dancing in a sort of conga line. I made the mistake of getting too close to this impromptu dance-off, and one of the kids wrapped me in a bear hug and picked me up off the ground. He pressed his head against me; his hair brushed across my face like a damp mop.

“I love you,” he said in halting English. I worked myself out of the embrace and asked a very amused Huebner whether he would mind taking me upstairs. We walked up a narrow staircase and emerged into a harshly lit corridor. The ground floor of the shul once served as the offices of the Rebbe, and several of his former aides — all non-messianists — were chatting quietly among themselves.

“Huebner,” one of them said. “What are you doing up here?”

A rabbi we passed hesitated before reluctantly shaking Huebner’s hand; he pretended not to see me. Others stopped when Huebner passed, whispering under their breath in Yiddish or shaking their heads almost imperceptibly. Some of the contempt was directed at me as Huebner’s guest. I kept my eyes trained on the ground, and when it became obvious we were no longer really welcome in the corridor, I said to Huebner in a loud voice that I was hungry.

“Let’s go eat,” he said. He must have felt my discomfort. On the way back to the house, he was mostly quiet. When we got closer to his home,

He turned to me and said, “You know, it’s easy to be a Meshicist in Crown Heights. It takes character to be a Meshicist out there in the world.”

A month later, I spent an afternoon walking Crown Heights with Benjamin Lifshitz. It was a blustery day, halfway through a snowstorm that would eventually blanket Brooklyn with a foot of snow, and Lifshitz was wearing a black coat and an NYPD ski cap pulled low over his eyebrows. For the Shomrim and the Shmira, blizzards are a blessing and a curse: crime is down, because criminals are usually too cold to do much of anything, but cars are always getting suck, batteries always dying. Lifshitz’s walkie-talkie spluttered with blasts of chatter from other Shomrim who were arrayed throughout Jewish Crown Heights, some on foot, others in enclosed three-heeled motorized scooters equipped with racks of red and white lights.

All Shomrim keep in touch via radios, which are issued when a member joins the group, along with an I.D. number and, in most cases, a uniform. Lifshitz, who is short and reedy, with soft brown eyes, would not tell me how many men are in the Shomrim — this wasn’t the sort of information he wanted available to the NYPD — but generally the ranks number between thirty and forty. I asked him whether I could see the official Shomrim command post, which is housed in a thirty-foot van parked at a repair shop called Everything Automotive, and Lifshitz agreed. We trudged down Albany Avenue toward the tenement houses of northern Flatbush. The sidewalks in this part of town open up in long, gray expanses, punctuated by vacant lots and burned-out old apartment buildings. In the distance looms the graying bulk of Kings County Hospital, where the bochurim had been taken after their confrontation with the Shomrim.

We crossed Lefferts Boulevard and walked two blocks down East New York Avenue, stopping at the bright blue door of Everything Automotive. Lifshitz rapped once on the window, and when no one answered we stepped into the cab of the Shomrim Mobile Command Post to get warm. The Shomrim purchased the van a few years ago at a police auction; they had once owned an even larger vehicle, but it was too difficult to maneuver on the narrow backstreets of Crown Heights. The new Command Post is filled with spare uniforms and radios, first-aid kits, and maps of Crown Heights, for use in grid searches. Lifshitz was showing me one of the maps when there was a loud banging at the door. Outside stood Aron Hershkop, the owner of Every-thing Automotive, his Shomrim radio hanging off the back of his utility belt.

“Man,” he smiled. “I saw someone digging around in the van — I was about to come and beat the shit out of them.”

I had met Hershkop several times before, and had found him gruff and standoffish, but today he looked pleased to see me. He had yanked the hood of his sweatshirt up against the cold; his pants were stained with streaks of grease. Hershkop owns several properties in Crown Heights, as well as working in the garage, where, in his spare time, he maintains the fleet of Shomrim cabs. A few years ago, the Crown Heights Shomrim drove mostly used NYPD squad cars, which they painted white and covered with Shomrim decals.

But as the feud between the Shomrim and the Shmira intensified — and the police began monitoring the Shomrim more closely — the Shomrim gave up their cars and took to patrolling only in the scooters, which Lifshitz says look less threatening. “There’s less of a chance someone is going to mistake us for the cops,” he told me. At last count, the Shomrim owned seven three- wheelers in various states of repair.

Hershkop asked us to wait for a moment, and when he returned he had a book in his hand, a family history: a grandfather who had survived forced labor in Samarkand; a great- grandfather beaten to death for trying to protect another Jew in the soup line of a different camp. Hershkop said he’d wanted to give the book to David Steingard, one of the two assistant district attorneys who had prosecuted the Shomrim Six, but his lawyer had advised him against it. I told him I’d love to read the book.

“Really?” He looked skeptical. “Sure,” I said. “I’ll bring it back in a couple of weeks.”

“Fast reader,” Lifshitz said, and pulled out his BlackBerry. “My mother,” he said, and began chattering in Yiddish. It turned out that Huebner had just served Lifshitz with another lawsuit, this time for the false imprisonment of a bochur. “What does he get out of a lawsuit,” he said. “My pants? I have nothing left.” He and Hershkop stood for a moment in silence. “It’s not over yet,” Hershkop said in Yiddish, and I watched him walk back through the doors of the garage, over which hung a large plush Incredible Hulk, its bright green faded to buttery pea soup under the snow.

The oldest yeshiva dormitory in Crown Heights sits on a quarter-acre slab of rumpled concrete at 749 Eastern Parkway, not far from the corner of Kingston Avenue. It is an ugly building, four stories high and chapped gray-white by the sun. One day in January I trekked out to the dormitory, and, finding the front door unlocked, I slipped into its airless lobby. I was there to look for Yaakov Shatz, the student who had testified against the Shomrim in Brooklyn Supreme Court. A friend had told me Shatz was leaving town, and now that he wouldn’t have to worry about censure from the community, I hoped he might be in a talkative mood.

On the second-floor landing, I heard the opening chords of “Heartbreak Hotel” plucked out on a badly tuned electric guitar. I followed the music to a black metal door. There was a great rustling and a peal of feedback, and the door opened, revealing a short, sweaty Hasid, his white dress shirt unbuttoned to his chest, his yarmulke hanging precipitously off a shock of brown hair. “Schneur Malka,” he said, extending a meaty paw and shaking my hand vigorously, as if he’d been waiting for me.

Malka’s room was low-slung, fetid, and damp. There must have been fifty pictures of the Rebbe in that tiny room — the Rebbe as a young bachelor, the Rebbe as a middle-aged man, the Rebbe after his stroke, on the verge of death. I asked Malka whether he had ever met Schneerson in person.

“Once,” he said, and clasped his hands to his heart.

“Do you believe he is the Messiah?” He smiled.

“Most people believe he is dead,” I said.

“What do they know of dead? He is not dead.”

“Then where is he?”

He shrugged. “Come,” he said. “We will look for Yaakov, okay?”

On the third floor, we were stopped by a knot of half-dressed bochurim, who spilled out of a room giggling and shrieking. As I got closer, I saw that one of the boys was carrying a shovel with a half-dead gray rat on it, its eyes flickering dully. Rats and mice are a huge problem in 749, and because Lubavitch leadership doesn’t provide extermination services, the residents are forced to do the hunting themselves. Whack! One of the kids had dropped the rat onto the ground and was using the blade of the shovel to cut its neck. A tiny splatter of blood burst forth, and the boys cheered.

Malka took me upstairs to a room on the fourth floor that had been charred from floor to ceiling; on the west wall was a blossom of black soot, where a fire had started. Apparently, a year before, a boy had decided to cook some food but then had been called down the hallway todaven, and had forgotten to switch off his George Foreman Grill. When he got back, the wallpaper was ablaze. Miraculously, the fire had not spread, though now the room was useless. A tattered plastic sheet covered the window frame, and Malka wrapped his arms around his shoulders to keep warm. “Look,” he said, and behind me I saw the only decoration that had survived the fire: a framed picture of the Rebbe — coated in soot and smoke stains — that thebochurim had not dared move.

Yaakov Shatz, it turned out, lived one floor down from the burned-out room; his roommate had been part of the mouse-hunting party. But when we got downstairs, Shatz was gone. His roommate said that he had been summoned to a warehouse on Albany Avenue to make matzos for the high holidays. “You like matzos?” Malka asked me.

Outside, the air was cold and sharp, full of the heaviness that comes before a major storm. We walked down Eastern Parkway, under oaks stripped bare by the wind, and turned south on Kingston. Malka threaded his fingers through mine and began to run. He ran like a squat, bowlegged bull, his chin tucked toward his chest. “I just made realization,” he shouted. “Matzos factory is closing!”

We arrived at the factory moments before the last batch of dough entered the oven. I usually like the earthy smell of matzos, but as I followed Malka through a crowd of bochurim, the aroma became thick and cloying, like the scent of rotten fruit. At a long wooden table, more than a dozen Russian women, their heads wrapped in brightly colored scarves, were pounding out circles of dough, each about twelve inches in diameter. There was no ventilation in the warehouse, no fire alarm, no natural light. Smoke collected in gauzy strands under the ceiling. Like many commercial operations in the neighborhood, this factory operated in a gray area; it wasn’t illegal, exactly, but then again, there was no signage out front, and Malka asked me not to specify the address, for fear the place might he shut down.

Shatz was in the back room, stripped to his shirtsleeves, helping a frail, gnomish man named Isaac shovel batches of bread into a roaring brick oven. Malka gave a short introduction in Yiddish, and although I didn’t understand most of what Malka said, I nodded sagely.

“You want to know about the fight,” Shatz said.

“If you wouldn’t mind.”

“Outside,” he said. We sat down on the curb to talk. “It was bad thing,” Shatz began. I fished for a pen and paper in my bag. “No, no,” he said. “I want to tell story in Hebrew. You find me translator. And then meet me here. Okay?” It took me two days to find someone willing to accompany me to the matzo factory, and by the time I got back to Albany Avenue, Shatz had left Brooklyn, traveling first to Israel, where he would visit his family, and then to India, where he would serve as a Lubavitch emissary. I never saw him again.

In early February, Gadi Hershkop was sentenced to three years of probation and a year of anger-management classes for his role in the assault at 749. In the days soon after, I called Hershkop and Lifshitz repeatedly, but they wouldn’t answer. Eventually I got sick of hearing the same voicemail greeting, and I took the subway out to Everything Automotive. I found Hershkop lying on his back on the floor of the garage, soaked in brake fluid, which was dripping off the undercarriage of a van and onto his shirt.

He was in a foul mood. A few days earlier he’d been approached by a private detective. The detective had apparently once worked for the Gotti family and came highly recommended; for $10,000, he promised to deliver a lengthy report on the forces within the Lubavitch community conspiring to bring down the Shomrim. Hershkop told me he had not yet decided whether to hire the detective. He certainly had the money — money, he said, was never the problem — but he wasn’t sure he wanted to take on anything new. He already felt overwhelmed by the strain of fending off attacks from Huebner and the rest of the Shmira.

Just as the courtroom is one front in the war between the Shmira and the Shomrim, so too is 311, New York City’s municipal-services hotline. By dialing 311, residents can notify the city about oil leaks or trash-strewn streets, or inquire about parking bans or snow emergencies. But 311 can also be used as a weapon. Hershkop says he has been plagued with calls from city inspectors, who have been — anonymously, of course — notified about possible labor breaches at his New York Avenue shop. A couple of years back, he told me, he was approached by two FBI agents. The men were nattily dressed but clumsy. “You know how you can see a cop coming from a mile away?” Hershkop asked, laughing. “It was like that. Something about the haircut. These two jokers walked up to me, flipped open their wallets, and said they were investigating me for some sort of payroll problem. I said, ‘Hey, investigate away.” There was no investigation.

Hershkop also claimed that his shop is being surveilled by undercover NYPD units. On one of the days I visited the shop, I’d noticed a white van at the corner of Albany Avenue, its engine kicking puffs of gray smoke into the winter air. Two men sat inside, their feet resting on the dashboard. According to Hershkop, these men had approached him at lunchtime, offering to sell him a bunch of cheap mattresses from Sleepy’s, a major New York chain. “We can sell these things to you at a major discount,” one of the men said. “Straight off the back of the boat.” Hershkop knew that as soon as he handed over the cash he’d be cuffed and arrested for black marketeering. “So I just told them to go away.”

The end of the trial had not in any way ended the feud. The Shmira were enraged that none of the Shomrim had been jailed, and Hershkop told me that he expected things to get worse. “They’ve threatened me, they’ve threatened my wife, they’ve threatened my kids, they’ve gone after everyone I love,” he said. “They’re animals.”

Days earlier, he had attended a birthday celebration for a neighbor’s son. “Halfway through the party,” he said, “I see this kid jeering at me, pointing at me, calling me all sorts of names.” Hershkop later found out that the boy was the son of Yanky Prager, one of the Shmira leaders.

I asked Hershkop why, if he knew that the Shmira were behind the phone harassment, the FBI agents, the undercover cops, the threats against his family, he didn’t just head to Shmira HQ and start cracking heads? Men have done worse to one another for less.

Hershkop’s wife was on the phone ordering station-wagon parts, and she nodded at me warily. “You ask why I don’t fight back physically,” Hershkop said. “First of all, I don’t fight like that because that’s exactly what they want — to see me in jail. But I also don’t fight like that because the Shomrim is known here as a group that does good, and we’ve got to keep doing good.”

Hershkop pointed to one of the walls of his shop, which was festooned with photographs of the Shomrim in happier days. There was a picture of Hershkop at a picnic, one of the Shomrim assisting at an accident scene, and a posed portrait of the Shomrim with Mayor Bloomberg. Next to these was a shot of Hershkop and his toddler son, who was dressed in a blue Shomrim jacket.

Frances FitzGerald, in her book Cities on a Hill, noted that American ethnic enclaves function as “single organisms or personalities,” with unified “kinship systems, customs, and rituals.” The Jews of Crown Heights had for many years benefited from such a biological construction. Consolidation made it possible for the Lubavitchers to survive in the Crown Heights of the Sixties and Seventies. Consolidation kept them here, protected them, fostered and preserved their community, allowed it to thrive. Yet consolidation had also ensured that the wounds inflicted on each other by the Shmira and Shomrim will never heal. Aron Hershkop and Levi Huebner live four blocks apart. In a community with its own rules and laws, where their world is the only world and the life beyond these streets leads inevitably to destruction, there is no opportunity for a peaceful resolution. All that’s left is to fight.

Research support for this article was provided by The Investigative Fund at The Nation Institute, now known as Type Investigations.