Mario Cárdenas Guillén
Mario Alberto Cárdenas Guillén is a former leader of the Mexican criminal group called the Gulf Cartel. He is the brother of Osiel Cárdenas Guillén and Antonio Cárdenas Guillén.Mario was imprisoned in Matamoros from 1995 to 2003, but was later transferred to another prison in Jalisco after the Mexican authorities concluded that he was still managing marijuana and cocaine shipments behind bars. In 2007, he completed his sentence and was released. When his brother Antonio was killed in 5 November 2010, Mario took the lead of the Gulf Cartel along with Jorge Eduardo Costilla Sánchez. But by then, the Gulf Cartel had separated from Los Zetas, the former enforcer gang of the cartel. Part of the Gulf Cartel, instead of lining up behind Mario, decided to work for Costilla Sánchez. This led for cartel's division and infighting between the two factions, where Mario and Costilla Sánchez turned their guns against each other and Los Zetas.On 3 September 2012, the Mexican Navy arrested Mario in the city of Altamira, Tamaulipas.