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).
Ismael Zambada García Ismael Zambada García (born 1 January 1948), also known as El Mayo Zambada, is a Mexican drug lord who serves as the leader of the Sinaloa Cartel. Before assuming leadership of the entire cartel, he served as the logistical coordinator for the Zambada-García faction of the Sinaloa Cartel which has assisted in the exporting of cocaine and heroin into Chicago and other U.S. cities by train, ship, jet and submarine.