This article originally appeared in the September 2017 issue of Texas Monthly with the headline “Dark Horses.”

Perhaps we misunderstand the border. By imagining it as a barrier against another nation’s politics and problems, we’ve allowed ourselves to shrug off any real connection to the drug war. We’re on our side, they’re on theirs, and the front is that line on the map between us. It’s a tidy way of conceptualizing problems we’d rather ignore. Violence, turf wars, and seedy characters; they’re all someone else’s concern.

It’s this wrongheaded idea that Melissa del Bosque’s Bloodlines: The True Story of a Drug Cartel, the FBI, and the Battle for a Horse-Racing Dynasty (HarperCollins) and Joe Tone’s Bones: Brothers, Horses, Cartels, and the Borderland Dream (One World/Penguin Random House) indict. The books (published, in one of those strange coincidences, nearly simultaneously: Tone’s book came out August 8, del Bosque’s is due September 12) chronicle the same story: the three-year investigation into a vast money-laundering network run by the Zetas, the Mexican paramilitary drug cartel. The focus of the investigation was Miguel Ángel Treviño Morales, a.k.a. the much-feared Zeta commander Z-40, who laundered millions of dollars in drug profits through the intense world of American quarter-horse racing.

Tone boils down the scheme thusly: “Buy a horse cheap with drug money, slide its ownership into a legitimate-seeming American company, and then either rake in the winnings or force someone, under the threat of grisly violence, to take it off the Company’s hands for a large sum of clean money.” The most unexpected twist, what distinguishes Treviño’s story from so many other narco narratives, is his unlikely partner in Texas: his ostensibly upstanding brother, José Treviño, a Dallas-dwelling brickmason who for decades lived an apparently law-abiding life until, in 2009, he turned himself into a money-laundering impresario.

In both books, action and intrigue spill off the pages: there are scenes of tense surveillance operations, feverishly manic horse races, confrontations between lawmen competing for their slice of investigative glory, unnerving meetings between Zeta operatives who have snitched and the bosses they’re hoping don’t realize they’ve snitched, and, at the end, a dramatic courtroom showdown. As we come to see, ranching, Mexican politics, the bonds of fraternity, and the strange world of quarter-horse racing bend to the pursuit of profit and the Treviños’ intricate designs.

Bloodlines and Bones are indebted to a stunning piece that Pulitzer Prize–winning journalist Ginger Thompson (who grew up in El Paso) wrote for the New York Times in 2012. The story Thompson told was ripe for further exploration; it’s not difficult to imagine why two publishers would jump at the chance to tell it at greater length. Yet expanding the narrative, with its winding series of events, investigative minutiae, and vast array of drug lords, horsemen, and lawmen, demands discipline, linearity, and simplicity. It is, at its heart, a crime yarn, one best told in a taut, lean voice.

This voice comes naturally to Texas Observer staffer del Bosque, a skilled reporter, unfussy writer, and a storyteller of intense focus. Her book opens up the world of investigative nuance and bureaucratic jostling that could, in less capable hands, feel arcane. The binding thread in Bloodlines is the young FBI agent Scott Lawson, who arrives in the dusty border town of Laredo from Tennessee to partner with a veteran FBI agent whom del Bosque calls “Alma Perez” and Tone refers to as “María Medina” (the agency requested she be referred to pseudonymously). Though Lawson isn’t the most charismatic of characters, he’s a relatable stand-in for the reader, and his hunt for the Zetas provides a firm anchor for del Bosque’s narrative.

Former Dallas Observer editor Tone, by contrast, opts for sprawl, to sometimes exhausting effect. While Lawson and his efforts eventually take center stage in Bones, Tone’s hyperactive sensibility prevents him from sticking with a single character for too long. He veers with abandon, his narrative flying across the southwest from Ruidoso to Nuevo Laredo to Oklahoma City and back. Despite the weight of detail in Tone’s book, there’s an odd dearth of voices, or the sorts of moments of psychological insight that mark the best narrative nonfiction.

Even though these are very different books, both effectively convey the borderlessness of narco-capitalism. The world of the Zetas requires a blurring of not only geographical distinctions but also criminal and legitimate business enterprises. Money laundering is an apt symbol of this dissolution: it’s an alchemy premised on the fungibility of material and living things alike. Drug profits become champion quarter horses with names like Mr. Piloto and Tempting Dash, who produce cash winnings; dirty pesos become dollars and then clean pesos. Between the Treviños, their henchmen, and the phalanx of law enforcement institutions on either side of the border, a picture emerges of an invisible network of corruption, violence, and profit crisscrossing everyday American lives, whether we care to acknowledge it or not.

The reality that both authors depict is of a border that offers no real resistance to the flow of illicit commerce and a system that strips ill-gotten gains of their blood-soaked origins. In total, the Treviños spent over $25 million on horses. The money—$1 million a month—streamed across the border and back again, making a mockery of law enforcement’s attempts to hold the line at the Rio Grande.

Yet for the FBI, the border has a very real presence. In the course of their investigation, Lawson and Perez/Medina agonize over their inability to fully assist in the investigation of a suspected cartel kidnapping of a pair of American businessmen in Laredo who disappeared on a trip across the border to Nuevo Laredo, a place just beyond the FBI’s reach. Such cases were “black holes of intelligence,” Tone writes.

After one of the abductees is murdered, the agents track down the killer in Laredo and engage in pursuit, until he once again crosses over to Mexico. Through Lawson and Perez’s eyes, del Bosque pans across a chain-link fence and the natural divide created by the “tall fronds of the Carrizo cane that lined the slow-moving river down below.” The agents know their target is so close, but given the line they’ve run up against, still so far. Lawson, del Bosque writes, “imagined the killer . . . watching them, his mouth curling into a smile. It was like standing next to a black hole. And there was nothing they could do about it.” In both books, that image of the black hole—suspects, information, and money sucked in by the drug trade’s confounding gravitational pull—is haunting.

The border once held a personal symbolism for José as well, a divide between the bad brother and the good. José had spent years helping build Dallas’s “exurban excess” with his “calloused hands,” as Tone writes. For José, crossing the Rio Grande into Texas as a young man offered him a chance to break with Miguel and build a different kind of life. But the lure of living as a big man, of finally unyoking himself from the story of the humble, hardworking immigrant, proved too great. Anything transformative about the spell that was cast over José when he crossed the border faded with time.

By the end of both books, the Treviños’ operation has been vanquished. But such victories against the cartels are the exception, not the rule, and only obscure how deeply implicated the U.S. is in the very problem we’re trying to solve. Our taxes fund the war against the Zetas, as our demand for their products funds the Zetas themselves. Our savings reside in the same banks as their laundered profits. As one Mexican businessman turned witness realizes after his horrific abduction and torture by the Zetas, “narcotrafficking and politics were like a snake devouring its own tail. There was no way to tell anymore where one began and the other ended.” The drug war is churning all around us. The option of turning away was never really an option to begin with. 

Sugar Land native and University of Texas graduate Siddhartha Mahanta is an associate editor at the Atlantic.