The DEA and Ayotzinapa

Washington, D.C., September 26, 2025 - The eleventh anniversary of the enforced disappearance of 43 Mexican students from the Ayotzinapa college brings a grim reckoning. To date, no one has been held accountable for the tragic “night of Iguala” that exploded on September 26, 2014. No mass graves have been located, no remains identified since the bone fragments of two boys found in 2021. Tomás Zerón, the Mexican official accused of orchestrating the cover-up that destroyed the early investigation, remains a fugitive protected by Israel. And the latest special prosecutor overseeing the case just stepped down, leaving the investigation in shambles; one parent of the missing students lamented that his tenure represented “three years lost.”

In a strange twist, however, this year did see criminal convictions of people connected to the Ayotzinapa case – but not for the disappearance of the 43 young men, and not in Mexico. Two members of Guerreros Unidos, the organized crime group accused of taking part in the 2014 attack against the students, pleaded guilty to heroin smuggling after separate U.S. trials. Adán Casarrubias Salgado, one of four brothers who ran Guerreros Unidos in Mexico, was sentenced in March to 11 years in federal prison. Pablo Vega Cuevas, the head of the group’s trafficking operation in Chicago, received a ten-year sentence but was given supervised release on August 19 for time served, after having cooperated with the U.S. Drug Enforcement Administration (DEA).

Though the two men were recently sentenced, the U.S. investigation into the Chicago cell of Guerreros Unidos unfolded over 16 months in 2013-14 – before, during, and immediately after the disappearance of the 43 students in Iguala, Guerrero. Along the way, the DEA collected evidence for their drug bust that included extraordinary information about the Ayotzinapa case, but the totality of the information didn’t reach Mexican prosecutors until 2022. One reason was that the government of then-President Enrique Peña Nieto failed to request the DEA case file for years, despite the urging of international investigators and the lawyers representing the boys’ parents. On the other hand, the U.S. Justice Department had little interest in sharing evidence it wanted to use against heroin traffickers distributing narcotics across the Midwest. As the DEA supervisor leading the case said in an interview, they were focused on “what’s prosecutable” – not human rights abuses.

To mark this eleventh year of the still-unresolved Ayotzinapa case, the National Security Archive is publishing for the first time key documents related to the DEA’s Chicago investigation. They include hundreds of text messages sent between the Chicago traffickers and their bosses and buddies in Mexico that were electronically intercepted by the DEA as evidence of the drug ring they were surveilling. But the intercepts also contain critical information about what happened on the night of September 26, 2014, the cover-up that followed, and who was responsible for attacking the students.

There were two separate releases of DEA intercepts – one was in April 2018 to the Peña Nieto government. Within days after the United States gave Mexico the text messages of Adán Casarrubias and Pablo Vega, someone in the Mexican Attorney General’s office leaked them to certain Mexican press outlets. Only after Peña Nieto left power and President Andrés López Obrador made a personal appeal to then-Vice President Kamala Harris for the remaining DEA intercepts were five more turned over to Mexico for the ongoing Ayotzinapa investigation. This posting makes public the original set of intercepts, released in 2018.

It’s impossible to say now what might have happened if that information had made its way into the hands of investigators in Mexico immediately after the boys were taken, but there is no doubt they would have offered critical leads that exist nowhere else. In that sense, the Chicago story within the Ayotzinapa case offers a cautionary tale about how drug war considerations can obscure and overwhelm the demand for accountability and justice for human rights. Neither Pablo Vega nor Adán Casarrubias were in Iguala the night the students disappeared, but both of them texted frantically with other Guerreros Unidos members about the attacks of September 26 after it became clear to them what had happened. Months later, once the Justice Department had announced the arrests of Pablo Vega and seven of his crew on narcotics charges, lawyers for the families of the 43 students began seeking meetings with the U.S. Attorney’s Office in the Northern District of Illinois to request their help in obtaining information about Ayotzinapa from the defendants. The Justice Department never granted them a meeting. Neither Pablo or Adán was made available to investigators or family members, nor were they required to tell the courts what they knew about the night of Iguala.

In an article that appeared in the Chicago Sun-Times about Pablo Vega’s sentencing last August, Assistant U.S. Attorney Andrew Erskine reportedly told the judge that Vega merited a lenient sentence because he had testified against Guerreros Unidos members and “helped investigators interpret what was being said on wiretapped cartel conversations.” No such help was ever extended to the parents of the 43 students to assist them in interpreting what the wiretapped messages might have contained about the night their sons vanished.

We preface the intercepts with an extended version of an interview we did originally for our podcast, After Ayotzinapa. The interview is with Mark Giuffre, who supervised the DEA’s Chicago case. His account of how his investigation unfolded and what the DEA learned along the way provides useful context for understanding the significance of the Guerreros Unidos text messages.

Mark served as a DEA agent for more than 30 years. He joined in the 1980s, when the Reagan administration was investing billions of dollars in drug interdiction abroad and law enforcement at home. Mark’s career took him from a posting in the Midwest to Thailand, where he spent years investigating drug trafficking and money laundering in the “Golden Triangle” of Southeast Asia (made up of the northern regions of Thailand, Laos, and Myanmar). By the time he returned to the United States in 2000, the domestic heroin trade was controlled largely by Colombians. But it was changing rapidly. Mark witnessed the rise of Mexican criminal groups in Chicago, where he was based; by the time the Ayotzinapa students disappeared in 2014, Mexicans dominated trafficking routes across the Midwestern United States.

In August of 2013, Mark was the supervisor of a team of DEA agents investigating high-level money laundering and financial crimes in Chicago. They were not working directly on narcotics smuggling; his team focused on cases involving the movement of the cash proceeds from drug sales in the Midwest. But in the course of their work, Mark and his agents realized that the money laundering operation they were investigating was connected to a major heroin trafficking ring run by a criminal gang they knew nothing about: Guerreros Unidos. Their discovery led to a months-long investigation of the group with wiretapping and surveillance and culminated in December 2014 with the indictment of eight Guerreros Unidos members.

A Department of Justice press release announcing those indictments attracted the attention of the Interdisciplinary Group of Independent Experts (GIEI, by its Spanish acronym), a group of international investigators working on the Ayotzinapa case in Mexico. For years afterwards, the GIEI repeatedly asked the Peña Nieto government to formally request copies of the text messages that DEA had obtained during the investigation; they believed that the communications between Guerreros Unidos members in Chicago and those in Iguala and other parts of Mexico would contain important leads for the Ayotzinapa case. And they were right. But both governments were slow to respond to the insistence of the international investigators, and they didn’t get the opportunity to analyze the intercepts in full until eight years after the boys disappeared.

Senior analyst Kate Doyle and reporter Anayansi Díaz-Cortes from Reveal (Center for Investigative Reporting) interviewed Mark Giuffre for the podcast After Ayotzinapa on September 9, 2020. Below are extended excerpts from the conversation in which Mark describes the DEA investigation into Guerreros Unidos in Chicago, how they discovered the gang’s use of passenger buses to smuggle drugs and cash, and what they learned about how this criminal group negotiated with the Mexican authorities so that their business could thrive unhindered.

The Interview

The DEA’s discovery of the Guerreros Unidos gang’s role in heroin smuggling in Chicago came after the arrest of two men who started cooperating.

We began to develop information through a number of our contacts and the information that surfaced – that was independently corroborated by multiple people – was that they were working for a cell that distributed significant amounts of heroin. And that cell was run by a man named Transformer, who they all feared.

Over the course of weeks and months of investigation, we were able to identify and verify that "Transformer" was Pablo Vega, that he ran a Chicago cell of this cartel, the Guerreros Unidos cartel, and that the leaders of that cartel in Guerrero, Mexico, included his brother, Marco Vega. Over time, through investigation and work with our office in Mexico, we learned that the cartel had actually been formed by Mario Casarrubias, Ángel Casarrubias, and Marco Vega collectively. Mario Casarrubias had Chicago ties. He had history in Chicago. He was in our intelligence database as a trafficker of narcotics dating back years ago. He had since gone back to Mexico, he worked for Beltrán Leyva [a major drug trafficking organization] for a period of time.…

So we knew that this cartel had Chicago ties. We knew that one of the co-founders of this cartel lived in the Chicago area, went to school in Aurora, Illinois, a suburb of Chicago. And in fact, we knew that Pablo was living in the Aurora area. We commenced surveillance operations on various members of the cartel who were active here in the Chicago area.

By October, the DEA had won approval from a federal judge to intercept the BlackBerry phones that Guerreros Unidos members used to text each other day and night. Eventually, Mark and his team were tracking the gang’s text messages wherever they were – in the United States and in Mexico.

And what was amazing about that was now, no matter where they’re traveling in the United States or internationally, we’re intercepting their communications. So we get to identify more and more people. There were people that you can tell – from the context of the conversation, the words being used and what was being spoken – were political figures at the highest level from Iguala and in Guerrero state [who] were communicating with various people that we were being ordered to intercept. [But] we’re focused on what’s prosecutable, what we have enough evidence to charge.

[As the surveillance] continued to develop, it reached a point where we knew that they were using buses. And we never had the detail to know where [the contraband] was in the buses, but we knew from the codes they were using that heroin loads were coming up in buses and that bulk cash, millions and millions of dollars, was going back down via the same method.

During surveillance operations, [the buses were] going to a warehouse where these Mexican passenger bus companies would be based when they were in the Chicago area. When they arrived, after they did their various drop offs in the neighborhoods – in the little village, in Pilsen or wherever – they would go to this location in Aurora and they would be serviced, they would get their oil changed, they would be cleaned. We had people there under surveillance while we were intercepting conversations.… And the [DEA] intelligence analysts showed us that when they were talking about the code name they used for heroin – “Yeah, we’re unloading it right now” – when they were having that conversation, surveillance had them at the warehouse. And that happened multiple times.

[…] So we knew. And what was difficult for us was – I don’t know if you've ever searched a bus before. I have. We actually had a bus searched that was suspect, that was related to this investigation. The local law enforcement, state police, whoever, took custody of the bus, claiming it was in violation of some conveyance rules or whatever. And we went out there, and with experts we removed every seat, every bolt, every nut, every valve, every... We took apart the bus and put the bus back together. We knew there was something in the bus… [but] we didn't find it! The dogs didn't find anything. The X-rays didn't find anything. … At the very end of the investigation, after we'd had some cooperation – we had statements from defendants and so forth – we knew that it was the bumpers in the buses. They were airtight. They were engineered, specially designed by an engineer in Mexico, [to be] airtight. And there was only one way to access the compartment. And there was only one engineer in America that had the tools and knew how to access that bumper. And there was only one engineer in Mexico who knew how to access and unlock that bumper.

Well, the dog didn’t hit on a bumper. It was airtight. There was nothing to be smelled on the bumper. The X-ray machine didn’t see anything when it looked at the bumper. But we learned later that the bumper that was going down was – the bumpers were filled with cash. Had it been coming up, you know, the codes would have been, “it’s filled with heroin.” But my point is, particularly with large conveyances, unless you have specific information – where were we looking? We were looking in all of the areas that we knew Mexican smuggling organizations used in buses to smuggle narcotics and cash. We had never encountered the bumpers before. And this was a technique that was very effective for them. And it was getting them across the border, back and forth, thousands of times.

[. . .]

We didn’t figure it out completely until after the indictments. An engineer told us and showed us the diagrams and pulled out the blueprints and showed us how. But that’s how sophisticated these organizations are – without specific inside information, even with electronic communications intercepts, you’re always putting the puzzle together.

We asked Mark to talk about how Guerreros Unidos managed its drug business inside Mexico. He told us that before Pablo Vega was tapped to head the group’s Chicago cell, his brother Marco Vega ran the operation, but in March 2014 Marco drowned while on a boating trip with his wife and friends on a lake in Mexico. Although official reports characterized his death as an accident, information later emerged that it was a revenge killing.

We knew from intelligence that when Marco Vega [was in Mexico] – before his passing – the intelligence information had implicated him in the assassination of a number of Mexican police officers. And we had multiple sources reporting that his accidental drowning was not an accidental drowning. It was his payback for ordering those murders. We knew from intelligence information and corroborated separately that Marco – and later Pablo, when he went down to Mexico for a period of time after Marco’s passing – we knew with high certainty that G.P.S. coordinates were being reported to them throughout the day and evening of roving Mexican military patrols.

Somebody embedded in those patrols was constantly reporting their latitudes and longitudes, almost hourly, day and night. So that gives you an idea of their own intelligence apparatus….

Why would cartels who are moving contraband, who are moving cash in illicit proceeds – why would it be to their benefit to want to know where government officials were at, where law enforcement is at, where the military was at? Why would these two Vegas, who were significant leaders and cartels, why would they care where Mexican patrols were located, where they were moving to, where they were? They had embedded people in these various units who were constantly [passing them that type of information]. I mean, it’s almost like a command and control center. You’re getting the location of your enemy or your adversary or your risk nonstop.…

Mark learned about the disappearance of the 43 Ayotzinapa students in almost-real time, as GU traffickers texted each other about what was happening in Iguala. But even before the incident, he and his team knew that Iguala was an important drug trafficking hub.

In the course of our investigation, when Pablo traveled to Mexico to control cartel activities – and for a short period of time to take Marco’s place – he was in Iguala. And we have – you know, he takes selfies of houses that he was staying at in Iguala. He talks about being in Iguala and having meetings with various associates and directors who had reported to Marco previously. So we knew from our intelligence and our research and the investigations that Iguala was essentially the stronghold of the Guerreros Unidos cartel. But it wasn't until [the students were disappeared] that it was like, you know, wow.

Eventually, intelligence gathered by the DEA proved that Guerreros Unidos was smuggling more than two thousand kilograms of heroin into Chicago every year, which was – as Mark says in the podcast – “an unprecedented, mind boggling amount.” We asked Mark if he and his team ever spoke directly to their Mexican counterparts about what they had found in their Chicago investigation.

That’s happening consistently throughout with personnel assigned to DEA offices in Mexico.… That’s why we have offices there, to be our resource for sharing information and intelligence. Later, you know, there were Mexican officials who traveled to Chicago and met with the U.S. attorney’s office and met with members of my staff and there was intelligence sharing that went on as well. But during the course of the investigation, there wasn’t any [dialogue with them]. When we’re up on electronic devices and we’re intercepting communications that involve people in Guerrero, we’re letting the Mexico [DEA] office know: “Hey, this is what we’re working on here in Chicago. And there’s components of [the cartel] that are active in Guerrero.” Once we recognized, based on the codes, that we were talking thousands of kilograms a year, when we were looking at the quality and the quantity, we were constantly briefing Washington, D.C., the Department of Justice, DEA headquarters, the Mexico office.

There was significant interest in it because nobody realized that a smaller cartel such as Guerreros Unidos could be such a major player in the heroin distribution in the United States. And, of course, we were in the beginnings of the heroin epidemic in America, right?

The Intercepts

The National Security Archive is publishing two sets of intercepted text messages from the DEA’s investigation into the drug trafficking operations of Guerreros Unidos in Chicago in 2014. One set is from the phone of Adán Casarrubias Salgado (alias “Silver,” “Tomato”), a Mexico-based GU leader. The other set is from the phone of Pablo Vega Cuevas (alias “Transformer”), chief of the GU’s Chicago operation. While the texts have been reported by both Mexican and international media over the years, this is the first time the full intercepts are being made public.

The text messages make clear that these two GU members did not have advance knowledge of the attacks on the students, but were reacting in real time to the violence as it was reported to them by their fellow gang members and in the press. The chaos created by the night in Iguala was a disaster for Guerreros Unidos: it undermined their control of the “plaza” (their drug trafficking territory in and around the city), exacerbated conflicts between each other and with other criminal groups, and weakened the protection they would normally receive from corrupt civil, police, and military authorities.

The gang needed to manage the consequences of the attacks for their business and for their personal security. Adán Casarrubias in particular, as a Guerreros Unidos chief, reacted to the news of what had happened by issuing a frenzy of orders to various subordinates in and around Guerrero designed to mask the involvement of his criminal organization in the violence and lay the blame on others. In one exchange, Adán (“Silver”) orders another GU member (“Romeo”) to obtain false testimonies from bus drivers, on whose buses the students entered Iguala, that the boys (called “Ayotzinapos”) had been carrying weapons and attacked civilians.

[September 28, at 8:22pm]

Silver: Have people testify that the guys were armed. [Tell that to] the people from [the bus company] Estrella Blanca, the drivers and everyone. That they intercepted the buses in Chilpancingo. That they were going to Acapulco and they boarded with arms.

Romeo: Yes sir. [The witnesses] are going to submit reports about the cars they stole, the taxis, and the stores they robbed. And the people they wounded. There are 3 civilians dead, including a child. That the Ayotzinapos attacked them.

Silver: Check with Estrella Blanca and get them to have the drivers testify that they were intercepted. Also the families of all the dead and wounded civilians. The woman they killed in a taxi.

Romeo: Yes sir. [. . .] How much should we give them?

Silver: How much do you need?

The disappearance of the Ayotzinapa students aggravated tensions between different factions inside Guerreros Unidos. According to the text messages, Adán’s brother Mario Casarrubias ran the heroin smuggling enterprise until Mario was arrested in Mexico on April 29, 2014. Mario’s competence and control in managing the business was replaced by the more aggressive, violent brothers, Sidronio (“El Chino”) and José Ángel (“El Mochomo”). After the Iguala police were detained for their role in attacking the buses the students were riding in, they told authorities that they took the Ayotzinapa students off the vehicles and turned them over to Guerreros Unidos. Pablo Vega and his romantic partner (“Spider Woman”) texted back and forth after learning that Sidronio Casarrubias was involved in the attacks.

[October 18, starting 3:37am]

Spider woman: The ones they captured said they handed over the 43 that disappeared to [Sidronio] and he accepted it.

Vega: Yeah that’s what they’re saying… Who knows where they ended up? […]

Spider Woman: We’ll see if it comes out tomorrow… then they’ll bring them out so we can see what happens.

Vega: They’re not bringing them out. They probably beat them badly.… But there they are, the evil guys.

Spider Woman: You think so? That’s true. Stupid people.

Vega: They threatened everyone. Oh well. We’ll see what’s next.

Spider Woman: He and Mocho [José Ángel Casarrubias] were the worst ones.

The texts are evidence of extensive corruption amongst all levels of government, including local and state authorities, the Mexican military, and the marines. In the immediate aftermath of the attacks in Iguala, the group scrambles to protect their collaborators in the government and local security forces. For example, “Romeo” reports to Adán about consulting with Francisco Salgado Valladares (referred to as “Valla” in the messages), second in command of the Iguala Police, about an order of protection for Valladares to avoid detention.

[September 27, at 2:22pm]

Romeo: Okay; Sir; because apparently they are going to detain everyone. I already told Valla to consult with Victoria for an order of protection; or something should be able to be done.

Silver: Okay. [End of Message]

After the mass arrests of police from Iguala and neighboring towns, Vega and “Spider Woman” exchange information they learned from news reports about Valladares receiving 600,000 pesos a month in exchange for his cooperation with the GU.

[October 18, starting 3:37am]

Spider Woman: 14 police from Iguala; 17 from Guerreros; and 13 from Cocula were taken to the prison in Tepic. And they caught them entering the State of Mexico with one of the lieutenants but they didn’t say his name.

Vega: Yeah, it’s coming out on the news.

Spider Woman: But it says that he stated that he would give them 600 thousand a month, to Valla as payroll.

Vega: Yeah; I’m hearing about it.

Despite the growing number of arrests in the days that followed, some inside Guerreros Unidos remained optimistic that business would resume as normal. After the detention of one GU associate, Adán frets that he will inform on the group by passing information to the authorities. Another GU leader (Adán’s brother, José Ángel Casarrubias, here called “Soldado del Amor”) dismisses Adán’s worry by claiming that a corrupt official (“Omar”) was just trying to scare Adán so that he could get a bribe to make the informant go away.

[September 28, at 5:39pm]

Silver: He knows that you’re receiving communications and using that pin, so he says he has to talk to you about something really delicate, not just any old thing. And then he’s passing the information on to intelligence.

Soldado de Amor: That bullshit is coming from Omar, my friend. Toughen the fuck up. And that’s a lie. Later, he’s gonna call you and ask for money, you’ll see. Nothing’s gonna happen dude, don’t freak out, that’s the way the fucking government works.”

Adán Casarrubias was arrested in Morelos, Mexico, in October 2015 on drug trafficking charges and held in “preventative detention” until his extradition to the United States on May 26, 2022. His plea deal in the Chicago heroin case all but guaranteed he would never be questioned about what he knew about the enforced disappearance of the 43 Ayotzinapa students. Another drug bust, another opportunity lost to learn the truth about the night in Iguala.