Zeferino Peña Cuéllar (died 23 December 2025), also known as Don Zefe, was a Mexican suspected drug lord and high-ranking member of the Gulf Cartel, a criminal group based in the state of Tamaulipas. He was part of the cartel during the 1990s and was a trusted enforcer of former kingpins Gilberto García Mena and Osiel Cárdenas Guillén. From 1999 to 2001, he served as the municipal police chief of Miguel Alemán. Peña Cuéllar reportedly relied on corrupt Mexican military officials to run drug trafficking activities in Tamaulipas. This group of military officers would later become the foundation for the creation of Los Zetas, the Gulf Cartel's former paramilitary group originally made up of ex-soldiers. In the cartel, he headed organized crime operations in the municipalities of Gustavo Díaz Ordaz, Camargo, Miguel Alemán, Mier, and Guerrero.
After García Mena was arrested in April 2001, several within the cartel blamed Peña Cuéllar for informing Mexican authorities of his whereabouts. This triggered an attempt on his life in October 2001 at one of his estates in Nuevo León. Though Peña Cuéllar was not there when the attack occurred, the incident raised his profile in law enforcement circles. Authorities effectively moved against many of his assets in subsequent investigations. Few details of his criminal activities are known; Peña Cuéllar remained active for a few years after the attack, but when several of his accomplices were arrested and/or killed, he disappeared from public view. Peña Cuéllar withdrew from organized crime for an extended period, fleeing Mexico and living in Canada and the United States with the fortune he accumulated during his criminal career. He later re-emerged from retirement and was located and killed by authorities during a shootout in Santiago, Nuevo León, in 2025.
Early life Peña Cuéllar was born in Tamaulipas, Mexico. He grew up in a large family with numerous siblings. He graduated from college with a degree in civil engineering. From 1999 to 2001, he served as the police chief of the Miguel Alemán Municipal Police force during the administration of the city's mayor, Raúl Rodríguez Barrera ("El Chupón"). Peña Cuéllar's father Israel Peña Barrera also worked for the local police from 1996 to 1998. Police reports state that Peña Cuéllar met Rodríguez Barrera before he became mayor. The two had become close friends working together on the police force. Peña Cuéllar was assigned the job of local police chief when Rodríguez Barrera became mayor. Peña Cuéllar was reportedly an informant for the Federal Judicial Police (PJF) in Tamaulipas when Rodríguez Barrera was working there. Their friendship grew once Rodríguez Barrera became mayor, and both were often seen together at public events.
Besides his police duties, Mexican authorities suspected that Peña Cuéllar also worked with the Gulf Cartel, a criminal group based in Tamaulipas. He reportedly worked alongside organized crime kingpin Gilberto García Mena ("El June") and his lead smuggler Edelio López Falcón ("El Yeyo"). They were responsible for heading drug trafficking operations from Tamaulipas to the United States. Peña Cuéllar also worked with the trafficker Fidel Hinojosa ("El Choco") and with Ricardo Garza Manríquez, the former Miguel Alemán Public Security Department head. Peña Cuéllar was originally García Mena's financial operator, but both eventually became involved in drug trafficking activities together.
In 1997, Peña Cuéllar recruited several military members who were stationed in Miguel Alemán to combat drug-trafficking groups in the region. Among them were Arturo Guzmán Decena and Heriberto Lazcano Lazcano, two military officers who were his bodyguards. They eventually hired other military men using their contact in the police, Aurelio Cano Flores. García Mena's legal team advised both men to hire mercenaries because illegal possession of firearms was considered a more serious crime than drug trafficking at that time. Investigators believe that García Mena's faction was allowed to conduct drug-trafficking activities with relative impunity by the corrupt officers. Peña Cuéllar was reportedly responsible for paying large amounts of cash to corrupt military personnel stationed in Tamaulipas. He collected the money he used to pay them from the U.S. Peña Cuéllar traveled there in a vehicle and smuggled the money back into Mexico in bags disguised and hidden with food supplies, with Lazcano Lazcano and Guzmán Decena providing armed protection. The military men he relied on would become founding members of Los Zetas, the Gulf Cartel's former paramilitary group that was originally composed of ex-commandos. Although he lacked military training, Peña Cuéllar is cited as a founding member of Los Zetas.
In April 2001, the Mexican Army carried out a massive manhunt in Guardados de Abajo, Camargo, that resulted in García Mena's arrest. One of Peña Cuéllar's properties was raided during the operation; multiple firearms were seized at his home, and authorities linked him to the Gulf Cartel. Authorities had information that Peña Cuéllar was hiding in a city in Texas when they raided his home in Miguel Alemán.
Assassination attempt On 30 October 2001, fourteen gunmen dressed in military uniforms stormed an estate in the Hacienda Santa Lucía neighborhood in Monterrey to kill Peña Cuéllar. They arrived at the property at around 5:45 a.m, and surrounded it with two Hummers and two Suburbans. The gunmen then entered the premises using several portable ladders that helped them to reach the estate's rooftop. Other gunmen destroyed the main entrance gate. A shootout broke out between the gunmen and Peña Cuéllar's henchmen. Around twenty of his gunmen were inside the premises when the shootout occurred. After nearly an hour of gunfire, Peña Cuéllar's men surrendered; some were kidnapped and taken forcibly to the assailants' vehicles. The gunmen then left the scene. On a nearby highway, they were intercepted by a police officer who was responding to the sounds of gunfire at the estate. They told the police officer they were part of the military and were carrying out an operation there. The gunmen then fled the scene and possibly headed to El Faisán and El Uro, two nearby neighborhoods. René Montiel Muñiz and Eduardo Luna Estrada, two of Peña Cuéllar's alleged operators, were injured in the attack. Daniel de la Garza Aguilar, a former police officer and chauffeur, was killed. Peña Cuéllar was not at the estate when the attack occurred, but he frequented it and had been there just hours before the attack.
When police officers arrived at the scene, Carlos Joel Torres Ortiz, a former customs agent and Peña Cuéllar's in-law, said he was the owner of the property. The Public Registry of Property and Commerce showed the property was registered to Alicia Magdalena García Armendariz, his mother-in-law. At the crime scene, investigators recovered several bullet casings from 9 mm, AK-47s, and AR-15 firearms. They also seized four handguns and two ammunition magazines. At a press conference the following day, Nuevo León authorities said the attack was likely part of a settling of scores within an organized crime group. Investigators confirmed Peña Cuéllar was notified that assassins were after him and had been able to leave the property before the attack. A tip that an attack was imminent first reached Cárdenas Guillén, who quickly notified Peña Cuéllar and warned him to protect himself. Peña Cuéllar reportedly left with an entourage of bodyguards. The day after the attack, the PGR arrived at the estate and investigated the property for about 45 minutes along with chemical experts. They did not mention the specifics of their investigation there.
Authorities were mainly interested in the attempt by organized crime members to kill Peña Cuéllar. However, other investigators did not discount the possibility the attack may have been carried out by members of the military—though they said this was unlikely because the assailants fled the scene shortly after the attack. Investigators said the attack likely stemmed from the arrest of García Mena. Initially, the Gulf Cartel suspected that López Falcón provided authorities with information that led to his arrest. However, the police suspected that the García Mena later discovered that it was Peña Cuéllar and not López Falcón who plotted against him. Another reason suggested by the police was the attack may have been ordered by López Falcón as revenge after he discovered that Peña Cuéllar started the rumor that he was responsible for García Mena's arrest. López Falcón was also a victim of an assassination attempt in May 2001 after he was blamed for García Mena's capture. By framing López Falcón, security forces suspected that Peña Cuéllar wanted to earn a high-ranking position within Cárdenas Guillén's chain of command.
Investigation and aftermath First year On 1 November 2001, the Mexican Army and agents from the Specialized Unit Against Organized Crime (UEDO) arrived in Miguel Alemán searching for Peña Cuéllar. They believed he was hiding in the area following an assassination attempt against him. During the operation, they also raided several houses owned by other suspected drug traffickers who were reportedly involved in the plot to murder Peña Cuéllar. Authorities dispatched a convoy through several neighborhoods with air support from a helicopter. Residents said they saw several Hummer vehicles in a number of neighborhoods that matched the description investigators had of those seen during the attack. The PGR questioned seven people linked to the estate, including the two survivors, Peña Cuéllar's in-laws, and the estate's interior decorator Jacobo Pedro González Suárez. Luna Estrada and Montiel Muñiz, the two men injured in the attack in Hacienda Santa Lucía, were placed under arrest, while being treated at a hospital in Monterrey. They were accused of illegal possession of firearms, using military-exclusive weapons, and involvement in organized crime. Luna Estrada refused to make a statement about the incident and asked to be moved to another hospital, but his request was denied. Doctors confirmed he was shot in the leg while attempting to flee during the shootout. Montiel Muñiz admitted he was armed and that he defended himself from the aggressors, but he said he could not identify the attackers. Autopsy reports showed that de la Garza Aguilar was shot in the back of the head and in his right hand.