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 the right-hand man of Jorge Eduardo Costilla Sánchez, the former leader of the criminal organization.