while others decided to leave and join the forces of Los Zetas. InSight Crime explains that the fundamental disagreement between the Rojos and the Metros was over leadership. Those who were more loyal to the Cárdenas family stayed with the Rojos, while those loyal to Jorge Eduardo Costilla Sánchez, like Flores Borrego, defended the Metros. Originally, the Gulf cartel was running smoothly, but the infighting between the two factions in the Gulf cartel triggered when Flores Borrego was killed on 2 September 2011. When the Rojos turned on the Metros, the largest faction in the Gulf cartel, firefights broke throughout Tamaulipas and drug loads were stolen among each other, but the Metros managed to retain control of the major cities that stretched from Matamoros to Miguel Alemán, Tamaulipas. Personal life Guillén was born in Matamoros, Tamaulipas, Mexico. Mario had two brothers working for the Gulf cartel: Osiel, who was arrested by the Mexican Army on 2003 and sentenced to 25 years in prison, and Antonio, who was killed during a confrontation with Mexican Marines on 5 November 2010. Mario has one son, Mario Alberto Cárdenas Medina (a.k.a. El Betillo), who was captured along with three others by the Mexican authorities in Matamoros, Tamaulipas on 9 June 2009. He confessed to have been a top lieutenant of the Gulf Cartel under his uncle Antonio Cárdenas, co-leader of the organization. Cárdenas Medina allegedly took control of the shipments of cocaine in the Playa Bagdad area before moving them north to the United States. Reports indicated that Mario's brother, Homero Cárdenas Guillén, was allegedly part of the Gulf Cartel in late 2010. On 30 June 2019, Mario's son was once again arrested by Mexican authorities. He was arrested in the State of Mexico with a female companion identified as Miriam "M." See also War on Drugs Mérida Initiative Mexican Drug War References External links Mexican police capture alleged cartel leader (archived) — CNN Presenta la PGR y SEMAR a Mario Cárdenas Guillén, presunto líder del Cártel del Golfo — Federal government of Mexico (Video) Gulf Cartel members Living people People of the Mexican Drug War People from Matamoros, Tamaulipas Mexican drug traffickers Mexican crime bosses Mexican prisoners and detainees Year of birth missing (living people)