 Mario Armando Ramírez Treviño was born in Mexico on 5 March 1962. For many years, he worked under the radar as he ascended in the ranks of the Gulf Cartel. In the early 2000s, he worked with Jaime González Durán (El Hummer), one of the leaders and founders of Los Zetas, an organization that served as the armed wing of the Gulf Cartel. El Hummer was eventually arrested in November 2008 and sentenced to 35 years in prison; Los Zetas later separated from the Gulf Cartel in early 2010 and went to war with them. But when the two organizations separated, Ramírez Treviño remained loyal to the Gulf Cartel and became the second-in-command in Reynosa, Tamaulipas, an area formerly controlled by the deceased Samuel Flores Borrego (El Metro 3). He was Flores Borrego's right-hand man in Reynosa. On 2 September 2011, however, the Mexican authorities discovered the bullet-ridden corpse of Flores Borrego inside a Ford Lobo truck on a highway that connects Reynosa with Monterrey. Although the information has not been confirmed, the Mexican Army alleges that Ramírez Treviño's boss was killed by "members of his own cartel," presumably on orders from the Gulf Cartel leaders Juan Mejía González (El R-1) and Rafael Cárdenas Vela (El Junior). Within a few hours after his death, Ramírez Treviño, who had been working as the regional boss of Ciudad Victoria, Tamaulipas, succeeded him as the kingpin of Reynosa. The top echelons of the Gulf Cartel gave him "explicit orders to make the [drug market] profitable again."
