Samuel Flores Borrego

Samuel Flores Borrego (a.k.a. Metro 3; 6 August 1972 – 2 September 2011) was a Mexican drug lord and high-ranking lieutenant of the Gulf Cartel. He was a former state judicial policeman who protected the ex-leader of the Gulf cartel, Osiel Cárdenas Guillén. Upon his arrest, Flores Borrego became a close associate of Jorge Eduardo Costilla Sánchez, the former leader of the criminal organization.

Although born in Matamoros, Flores Borrego was closely linked to the cities of Miguel Aleman, Tamaulipas where he was the plaza boss for the Gulf Cartel for several years after the arrest of Gulf Cartel boss Osiel Càrdenas Guillén and Reynosa, Tamaulipas, where he had the biggest impact after taking over after the death of fellow drug lord and close associate Héctor Sauceda Gamboa, who was also the brother of fellow Metro founder and another close associate to Flores Borrego, Gregorio Sauceda Gamboa.

The Mexican authorities believe that Flores Borrego is responsible for the split of the Gulf cartel and Los Zetas, a cartel originally formed by deserters of the Mexican Army Special Forces hired in the late 1990s as the private army of the Gulf cartel. While operating in Reynosa in early 2010, Flores Borrego ordered the abduction and execution of a leader of Los Zetas. After the slaying, Los Zetas demanded Flores Borrego's death and threatened to go to war if the Gulf cartel did not hand over the assassin. Nonetheless, Flores Borrego ignored their demands and consequently broke the organization's alliance.

On 2 September 2011, Flores Borrego was found dead along with a local police officer on the outskirts of the border city of Reynosa, Tamaulipas. The Mexican authorities indicated that he had been killed by members within his own criminal group over disagreements and territorial disputes.