It is perhaps Mexico’s most notorious cold case — 43 college students shot at by the police, forced into patrol cars, handed over to a drug cartel and never seen again.
The mystery has haunted the nation for nearly a decade. How could a relatively unknown gang pull off one of the worst atrocities in Mexico’s recent history, with the help of the police and the military watching the mass abduction unfold in real time?
A vast trove of about 23,000 unpublished text messages, witness testimony and investigative files obtained by The New York Times point to an answer: Just about every arm of government in that part of southern Mexico had been secretly working for the criminal group for months, putting the machinery of the state in the cartel’s hands and flattening any obstacle that got in its way.
The police commanders whose officers snatched many of the students that night in 2014 had been taking direct orders from the drug traffickers, the text messages show. One of the commanders gave guns to cartel members, while another hunted down their rivals on command.
The military, which closely monitored the abduction but never came to the students’ aid, had been showered with cartel bribes, too. In the text messages, which were caught on wiretaps, traffickers and their collaborators griped about the soldiers’ endless greed, calling them “whores” whom they had “in the bag.”
One lieutenant even armed gunmen connected to the cartel and, a witness said, helped the police try to cover up their role in the crime after the students were kidnapped and killed.
It has long been known that police officers and an assortment of government officials either helped the cartel abduct the students, or watched the crime happen and did nothing to stop it.
But the text messages have been a breakthrough for investigators — offering the clearest picture yet of a possible motive for the collusion between the authorities and the killers.
Fewer than two dozen of the exchanges have ever been made public. What the thousands of others reveal is staggering: Far beyond buying individual favors, the cartel, known as Guerreros Unidos, had effectively turned public officials into full-blown employees.
The government’s subservience is what made the mass killing of 43 college students possible, investigators say. And the loyalty ran deep.
One of the emergency responders who rushed to the scene of the mass abduction that night had an unofficial second job — gathering intelligence for the cartel. For months, the wiretaps capture him sending minute-by-minute updates on law enforcement’s every move to a Guerreros Unidos leader he called “boss.”
A coroner also did the cartel’s bidding, sending photos of corpses and evidence at crime scenes, the messages show.
After killing some of the students, the traffickers incinerated the bodies in a crematory owned by the coroner’s family, investigators say. In unpublished testimony, one cartel member told the authorities that the ovens were routinely used “to make people disappear without a trace.”
The text messages may also help answer another open question in the case: Why did Guerreros Unidos execute a group of 43 students who were training to be teachers and had nothing to do with organized crime?
In the months and weeks before the abduction, the wiretaps show, the cartel had grown increasingly paranoid, beset by deadly infighting and scrambling to defend its territory as rivals pushed in.
So, when dozens of young men swept into the city of Iguala on passenger buses — not unlike the ones the cartel used to smuggle drugs into the United States — the traffickers mistook their convoy for an intrusion by enemies and gave the order to attack, prosecutors now say.
Nine years after the students vanished, no one has been convicted of the crime, turning the case into a symbol of a broken system that cannot solve even the most brazen acts of brutality. The previous government was accused of orchestrating a sweeping cover-up to hide the involvement of federal forces in the abduction, especially the all-powerful military.
Now the investigation is at a critical juncture. Under President Andrés Manuel López Obrador, the authorities have ordered the arrest of 20 Mexican soldiers in connection with the kidnappings, including more than a dozen in June. The unpublished wiretaps have been crucial to building the case.
The cartel’s conversations were intercepted by the U.S. Drug Enforcement Administration in 2014 while investigating the cartel for trafficking drugs into suburban Chicago. Mexico sought the text messages for years, but American officials handed over the 23,000 only last year, in part because of a lingering distrust of the Mexican government, an investigator said. The D.E.A. declined to comment.
The messages obtained by The Times do not cover the night of the disappearance, and key details of what happened to the students are still unknown.
What’s clear is that the horror started on Sept. 26, 2014, when dozens of students from the Ayotzinapa Rural Teachers’ College traveled to Iguala, in the state of Guerrero. They commandeered several buses to go to a march in Mexico City, a tradition the authorities had tolerated in the past.
This time, they never made it past the city limits.
Minutes after the students left the bus station, the police chased them down, opened fire and hauled them away. Multiple cartel members have testified that the victims were turned over to the criminal group, which killed them and disposed of their bodies.
The army received constant updates about the crime as it happened. Soldiers were on the streets and a local battalion even had an informant embedded with the students, investigations have shown.
Army intelligence officials were also listening. They were spying on a cartel boss and a police commander as they discussed where to take some of the students that night, military documents show.
And days after the attack, the army knew the location of two suspects talking about releasing students who, investigators say, may have still been alive.
How the military knew this is now clearer — it was using a powerful spy tool manufactured in Israel, known as Pegasus, to surveil the gang’s members, an investigator told The Times.
But the military didn’t share the intelligence with officials searching for the students, and there’s no evidence that the armed forces tried to rescue them, according to investigators who have spent years looking into the case.
“They had all this information, but they hid it,” Cristina Bautista Salvador, the mother of one of the missing students, said of the military. “Instead of looking for our children or telling us the truth, they protected themselves.”
Mexico’s secretary of defense did not respond to a request for comment. Mexico’s president has argued that the accusations against a handful of soldiers are not a sign of broader corruption within the ranks.
“You cannot stain an entire institution because of the actions of one official,” Mr. López Obrador said in July.
Investigators trying to uncover the full extent of the military’s involvement have been stymied for years.
The government’s top human rights official was spied on while investigating the armed forces’ role in the mass disappearance. A prosecutor who led the case against the soldiers fled the country in fear late last year.
Then in July, a separate group of international investigators said they were giving up on their own yearslong probe into the crime, citing “obstruction of justice” by Mexico’s military.
But investigators say that no amount of obstruction can hide the collusion laid bare in the wiretaps.
The evidence “is very robust, strong, unquestionable,” said Omar Gómez Trejo, the Mexican prosecutor who went up against the military and then fled to the United States after the backlash made him fear for his safety. “It corroborates how the cartel operates and the connections it had to the authorities, including the army.”
‘All they want to do is take and take’
Reading the cartel’s text messages for the first time last year, in a conference room in the Drug Enforcement Administration’s headquarters in Chicago, Mr. Gómez Trejo realized he had been handed a gold mine.
It had taken years for Mexican officials to get their hands on some of the wiretaps, unleashing criticism in Mexico that American officials had withheld crucial information. Now the D.E.A. had finally given him and his team access to a broad set of intercepts covering months of cartel communications.
“We kept looking at each other” in amazement, Mr. Gómez Trejo said of the wiretaps. “You marvel at the fact that you’re seeing a revelation.”
By that time, the Biden administration had listed Guerreros Unidos among the criminal organizations “that pose the greatest drug threat to the United States,” and much had been written about the cartel’s efforts to corrupt elected officials.
But here were the traffickers and officials admitting to it themselves, in private conversations when they thought no one else was listening.
“Do you want me to get your whore of a city councilor in line,” one cartel member asked a local mayor on his payroll, “or should we put him down?”
The mayor responded one second later: “I’ll bring him to you. He’s a good worker.”
The state of Guerrero, where the cartel operated, is one of the poorest states in Mexico, but its mountainous terrain is fertile ground for opium poppy plants filled with the raw material for heroin. So, while the gang spread terror, it was also a rare source of extra cash.
The drug lords often spoke of buying off officials in cryptic language, using nicknames for collaborators and codes for everything from cocaine and kickbacks to large caliber rifles.
So Mr. Gómez Trejo’s team pored over every word of each exchange, using reams of investigative files to develop a type of Rosetta stone to decipher the cartel’s penetration of the state.
The traffickers talked about bringing “crabs” or “crab soup” to the military — a reference to money, a cartel member told investigators, because when you hold up your hands like crab pincers, it looks like you’re clutching an imaginary stack of cash.
At times, the traffickers reveled in their influence over such a powerful institution.
“What, you don’t think blondie has the soldiers in the bag?” one cartel member wrote, referring to a fellow gang member, investigators say.
In other moments, they seemed resentful of the soldiers’ demands. “They asked my brother to do the lieutenant a favor,” griped a trafficker.
“All they want to do is take and take,” responded a police commander who helped manage the cartel’s relationship with soldiers.
The hassle seemed to pay off. Cartel members talked about relying on the armed forces to help keep their rivals out of their territory, and using their connections to the military to get out of trouble with uncooperative authorities.
In one message, the police commander says he went with a military officer and a cartel boss to arm gunmen in a nearby town.
When asked whether he knew about the military officer getting a “little gift” from the cartel, the police commander replied: “He’s happy.”
‘We are 1,000 percent with you’
The students had no way of knowing just how deeply the cartel had burrowed into every corner of life in its stronghold in Guerrero, investigators say.
“Entering Iguala was like going into the mouth of the wolf,” said Carlos Beristain, one of the international experts who investigated the case.
One cartel member was a butcher. A local blacksmith built hidden compartments for stashing heroin and cocaine inside buses destined for the United States. A group of particularly violent brothers in the gang manned a carwash.
The emergency responder said he was introduced to the group because an acquaintance from high school was dating a cartel member, according to his sworn statement.
He said that when he tried to stop working for the group, he was kidnapped on the orders of a cartel assassin, tied up and beaten until he relented.
“From that day on, I acted as an involuntary informant,” he said, serving as a point person for the gang’s network of street-level lookouts.
The wiretaps show the extent of his responsibilities. He sent cartel leaders barrages of messages tracking law enforcement’s every move, including when they simply stopped “to buy agua frescas.”
The wiretaps also reveal another collaborator: a city coroner. In the text messages, he says his colleague’s brother was a hit man. The coroner used the connection to warn the cartel when assassins were targeting its members.
He discussed receiving cars from the group and declared his loyalty to its Chicago leader, Pablo Vega Cuevas — who has since pleaded guilty to drug charges in the United States — calling him “my boss.”
“I’ll never turn my back on you,” he told the leader. “You guys are like my family.”
Less cooperative officials got death threats.
“Can the mayor exchange dollars for us?” the Chicago boss asked a fellow cartel member in Guerrero.
“Yeah cousin, you know if he doesn’t want to I’ll threaten the asshole,” came the response.
Guerreros Unidos paid some police officers monthly, witnesses said, a kind of retainer that allowed the cartel to call on the authorities whenever it wanted.
“You tell yourself, ‘I know I’m committing a crime,’” a police officer said, according to a previously unpublished transcript of his interrogation by law enforcement. But it was impossible to resist regular $50 payments, he said.
“You say, ‘I’m not going to take it, so I don’t get myself into trouble,’ but then you say, ‘No, wait,’” he said.
When cartel members needed to pass through a checkpoint, move weapons or ambush their rivals, they turned to the police.
“Don’t worry, cousin,” a police commander told a cartel member in one message, “you know that we are 1,000 percent with you here.”
A few months before the students’ abduction, the cartel sent up a flare that showed just how anxious it was about possible rivals setting foot on its territory.
On a Sunday afternoon, traffickers warned that members of an enemy group had stopped by the local market for lunch. Within minutes, the cartel figured out what car they were driving, what they looked like and which food vendor they were near.
“Locate a red Nissan truck, double cab, there will be two men and a woman,” a trafficker texted a police commander in Iguala.
“The units have been alerted, and there’s one unit at the toll both,” the commander texted back.
“When the group decided that something needed to happen, it happened,” said Mr. Beristain. “The group had control over the different authorities and could tell them what they had to do.”
‘He doesn’t want to be number 44’
On Friday night, Sept. 26, the cartel spotted something out of the ordinary and sent out a warning, according to Mexican prosecutors.
Members of an enemy group were barreling through Iguala, interspersed with students on stolen buses, a cartel boss told the group’s leaders.
Only it wasn’t true. There were no rival traffickers aboard, investigators say, and other than the sticks and rocks they carried to seize the buses, the students were unarmed.
But the cartel had been on edge for months.
One of its top bosses had recently drowned, another had been arrested and the brothers who were left in charge had lost trust within the ranks, the wiretaps show. The traffickers fretted about a member who had defected to a rival cartel and a murder that appeared to be an inside job.
“My cousin was killed and it was our own people,” the Chicago leader told an associate.
“We cannot trust anyone, absolutely anyone,” the wife of the drowned cartel leader said in another exchange.
The group’s enemies appeared to take note of its vulnerability. In the weeks before the students disappeared, local media reported that the cartel’s rivals had “regrouped” — and were coming for Guerreros Unidos.
The wiretaps lit up with the traffickers fuming about gun battles around Iguala.
“This is going to get uglier,” the Chicago leader said in late August.
A month later, when Guerreros Unidos got the message about its supposed rivals plowing through on buses, its network of collaborators flew into action.
The two police commanders who had exchanged regular text messages with the cartel led the first attacks on the students that night.
As the students tried to leave Iguala aboard several buses, police officers under the commanders’ control blocked the streets and shot at them, striking some, including one who remains in a coma. The students were then loaded into patrol cars, vanishing soon after.
Several miles away, more police officers stopped another bus of students, used tear gas to get them off, then snatched them away.
They, too, were among the 43 who disappeared.
The emergency responder on the cartel’s payroll said he got two phone calls that night. One of the police commanders asked him “who he should hand over the ‘packages’” to, referring to the hostages. A cartel assassin also called, asking who was bringing him “the packages,” according to his sworn statement.
Exactly what happened next remains a mystery.
According to one cartel member whose testimony has become key to the case, some of the students were taken to a house, killed and dismembered. Machete hacks left gashes in the floor, the witness said, and the students’ remains were later burned in the crematory owned by the coroner’s family.
The military knew where at least some of students were being taken, because it was spying on a conversation between a police commander and a cartel boss as they talked about where to deposit the hostages, according to documents made public by the Mexican government.
Other military intelligence documents, which have not been published, show that the military knew the location of a cartel member involved in the kidnapping days after the attack.
Many of Guerreros Unidos’s leaders in Iguala were arrested after the attack. But no one has been convicted in the disappearance. Charges against dozens of suspects have been dismissed because a judge determined that torture was used to obtain confessions.
The group managed to stay alive, thanks in part to some of the drug lords’ wives and one of their mothers, who took over much of the day-to-day business, according to a separate set of hundreds of unpublished exchanges caught on wiretaps.
Years after the mass disappearance, the Mexican government continued spying on several people in the group, listening to their phone conversations in 2017.
The ties between the cartel and the authorities were still strong.
One of the traffickers involved in the kidnapping talked about how he had just “gotten drunk with the soldiers” at a local restaurant, the wiretaps show. A money manager for the cartel said he had made friends with a federal police commander. A city councilman talked about moving drugs to the United States.
One night, the wife of a jailed boss lost track of a shipment of drugs on its way to the United States. Thinking the smuggler might have made off with the stash, she asked an associate to give him a warning.
“Doesn’t the driver know what happened to the 43,” she said, referring to the abducted students. “I’m sure he doesn’t want to be number 44.”
Alan Feuer contributed reporting from New York, and Emiliano Rodríguez Mega from Mexico City.