Mario Cárdenas Guillén is the brother of the Mexican drug lord who was the former leader of what group?
Osiel Cárdenas Guillén Osiel Cárdenas Guillén (born May 18, 1967) is a former Mexican drug lord and the former leader of the Gulf Cartel (Spanish: "Cártel del Golfo" ) and Los Zetas. Originally a mechanic in Matamoros, Tamaulipas, where he was born, he entered the Gulf Cartel by helping Juan García Abrego, the capo at the time; when García Ábrego was arrested in 1996, some infighting erupted within the cartel. Osiel Cárdenas eventually took control by killing his friend and contender Salvador Gómez, earning Cárdenas the nickname ""El Mata Amigos"" (The Friend-Killer).
Roberto Hernández Ramírez Roberto Hernández Ramírez (born 1942 in Tuxpan, Veracruz) is a Mexican businessman. He is a former CEO of "Banco Nacional de México (Banamex)", Mexico's second largest bank, just after BBVA Bancomer, from Spain. He is currently a member of the administration board of Citigroup. Chairman of the Board, Banco Nacional de Mexico, S.A. - 1991 to present; Chief Executive Officer, Banco Nacional de Mexico, S.A. - 1997 to 2001; Director, Grupo Financiero Banamex, S.A. de C.V. - 1991 to present; Co-founder, Acciones y Valores Banamex, S.A. de C.V., Chairman -1971 to 2003; Chairman of the Board, Bolsa Mexicana de Valores, S.A. de C.V. (Mexican Stock Exchange) - 1974 to 1979, Director - 1972 to 2003; Member of the International Advisory Committee of the Federal Reserve Bank of New York - 2002 to present; Chairman, Asociacion Mexicana de Bancos (Mexican Bankers Association) - 1993 to 1994; Member, Bolsa Mexicana de Valores, S.A. de C.V. - 1967 to 1986; Director of Citigroup since from 2001 to 2009; Other Directorships: GRUMA, S.A. de C.V. and Grupo Televisa, S.A.;