A Kingpin’s End: The Death of Mario Ramírez Treviño

Mario Ramírez Treviño, alias “El Pelon” or “X20,” the former head of the notorious Gulf Cartel, passed away on March 13, 2025, while incarcerated in the United states. The Department of justice has formally requested the Columbia District Court to dismiss the criminal charges and cancel the pending sentencing hearing against him, signaling the end of a significant chapter in US-Mexico judicial cooperation on drug trafficking.

The motion, filed on March 21, 2025, officially states the defendant’s death and requests the case’s closure. Prosecutors Janet Turnbull, Church Handrich, and Jayce Born from the Justice Department’s Narcotics and Dangerous Drugs section signed the document.

From Police Officer to Cartel Boss: A Tumultuous Career

Born on March 5, 1962, Ramírez treviño’s journey began as a police investigator before he transitioned into the ranks of the Gulf Cartel, ultimately rising to become one of its principal leaders. His career trajectory underscores the complex interplay between law enforcement and organized crime in Mexico.

During the 2000s, he spearheaded the “Los Rojos” faction in Reynosa, solidifying his power after the split with Los Zetas in 2010. By 2013, following the death of Miguel Villarreal “el Gringo” and the downfall of other key figures, Ramírez Treviño emerged as the supreme leader of the organization.

His leadership was marked by strategic alliances with the Sinaloa Cartel to challenge Los Zetas’ dominance in key areas like Monterrey. He also directed operations to eliminate rival factions within the Gulf Cartel, triggering violent conflicts in Tamaulipas. In 2010, the Treasury Department designated him under the Kingpin Act for leading international drug trafficking operations.

Extradition, testimony, and Untimely Death

Ramírez Treviño, 63, had been in US federal custody as his extradition in December 2017, following his capture by Mexican forces in Reynosa, Tamaulipas, in 2013. He faced federal charges related to drug trafficking and money laundering but had not yet received a final sentence at the time of his death.

His case, filed under 1:08-cr-00057-TNM in the Columbia District, had seen its sentencing hearing repeatedly postponed. This delay was perhaps linked to his role as a cooperating witness in the case against Rubén Oseguera González,alias “El Menchito,” son of Nemesio Oseguera Cervantes,”El Mencho,” the leader of the New Generation jalisco Cartel (CJNG).

In February 2024, Ramírez Treviño testified as a witness for the US Prosecutor’s Office, with his statement publicly revealed on September 16, 2024, during El menchito’s trial. He recounted meeting Oseguera González at the Altiplano Federal Criminal facility in 2014.

He arrived quiet… in later reunions he described him as ‘more violent, higher (…) according to him, it was already the second, his father had told him.’

Ramírez Treviño’s testimony was used as evidence against Oseguera, who was convicted of drug trafficking and firearms offenses on September 20, 2024, and sentenced to life imprisonment plus 30 years on March 7, 2025, just six days before Ramírez Treviño’s death.

He stated that they shared time in the Special Treatments Unit with other inmates like Servando Gomez “La Tuta” and Omar Treviño Morales “Z42.” He claimed that “Z42” asked “El Menchito” to help him acquire a ton of cocaine for $15 million,and that Rubén Oseguera himself requested assistance in obtaining an M60 machine gun and a .50 caliber rifle.

Unanswered Questions and Case Closure

Captured on August 17, 2013, by the Mexican Army and Navy in Reynosa, he remained imprisoned in Mexico untill his extradition to the US in December 2017, where he faced charges for trafficking large quantities of cocaine and marijuana, and also money laundering.

During his time in federal prison, he served as a witness in several judicial proceedings, and his health reportedly deteriorated significantly. In his last court appearance in February 2024, he appeared pale, thin, and struggled to breathe.

With his death, the US government has formally requested the court to close the case. The motion is based on rule 48(a) of the federal rules of criminal procedure, which allows for the dismissal of charges upon the death of the accused.

The exact medical causes of his death and the conditions surrounding it remain undisclosed. His death marks the end of a significant case in the judicial cooperation between Mexico and the United States in combating drug trafficking.