This week, ProPublica and Audible are launching an audio documentary called “The Making of a Massacre.” It’s the story of a vicious attack on a small Mexican ranching town called Allende, less than an hour’s drive away from the United States border. And it’s based on a ProPublica project, which showed for the first time how the violence was triggered by a tragically compromised Drug Enforcement Administration operation in Dallas.

Hear an Excerpt

The operation was aimed at bringing down the leaders of the Zetas cartel, considered one of the most violent drug trafficking organizations in the world. Agents had managed to convince one of the cartel’s leading traffickers in Dallas to get them intelligence that could allow them to track the movements of the Zetas kingpins. But the agents mishandled the information. When the Zetas realized they’d been betrayed, they launched a campaign of violence that went on for months. Dozens, possibly hundreds, of men, women and children were kidnapped and killed.

We decided to write and produce this audio project as an oral history because we wanted listeners to hear from the people whose voices are not often included in stories about the drug war. Among them are: the courageous women caught in the crossfire, angry with grief over the senseless loss of loved ones. The DEA agent at the center of it all, with the weight of the events heavy in his voice. The former mayor describing the insidious way traffickers took over his town. Even former cartel members, who casually detail the grip their murderous bosses had on the region.

We translated the interviews from Spanish to English and asked accomplished Latino actors to read key roles, including Cheech Marin, Alana de la Garza, Danny Trejo, Clifton Collins Jr. and Snow Tha Product.

The result is a story that provides rare insight into how cartels take control of Mexican towns close to the U.S. border, how American agents run secret operations in Mexico trying to capture them, and the tragic consequences that can occur when those well-intentioned efforts are compromised. You’ll hear from a prosecutor who has dedicated much of his career to chasing the Zetas leaders, despising the damage they’ve done to the country where his parents were born. You’ll also meet former cartel operatives, like José Vasquez, who describe the Zeta’s ruthless pursuit of power, and the DEA miscalculation that triggered the cartel’s attack on Allende.

The project also features the men, woman and children whose lives and deaths provide some of the most memorable moments in the story. Jose Piña simply asked the Zetas to stop running drugs across his ranch. A mother at the massacre site pleaded with the Zetas to let her teenaged boys go. An 81-year-old woman was torn away from her 6-month-old great-grandson. And there’s a 15-year-old boy, tall, with blue eyes, who went out for pizza with his friends and never came home.

Over the last decade, I’ve done a lot of reporting about the U.S. role in Mexico’s drug war. But as much as I had managed to learn about how the DEA operates, I had never before contemplated what role the agency’s work played in the war’s staggering death toll. American authorities aren’t eager to talk publicly about it. As far as I can tell, no one had contemplated these events through the lens of American accountability until ProPublica began this investigation.

Perhaps the frankest and most moving accounts in the story come from the women I met. Whenever I land in Mexican towns like Allende, places almost numbingly under siege, I look first for women. I find that women are less afraid, when it comes to their families and their communities, about upsetting the powers that be. That proved true again in this case, even when the powers were one of the most violent cartels in the world.

The courageous women you’ll hear from in this piece make devastatingly clear what the drug war really costs. It’s not money. It’s innocent lives. Claudia Helena Sanchez, a psychologist, lost her Gerardo, the 15-year-old who had gone out for pizza. Etelvina Rodriguez, a teacher, lost her husband, Everardo Elizondo. They have a small son. And María Eugenia Vela, a lawyer, lost her husband, Edgar Ávila. He was an engineer and managed a factory in Piedras Negras. When Edgar disappeared, they had a daughter, and Vela was pregnant with their second child, a son.

These women shared their stories despite great personal risk. Yet their own government has lacked the same courage. In seven years since the massacre, Mexican authorities have declared many of those people dead, and given their relatives death certificates. But they’ve not charged a single person with the murders.

Listen to the gripping 5-part series “The Making of a Massacre” at audible.com/massacre. It’s free for Amazon Prime and Audible members.