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 on 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. He was extradited to the United States on the 17th of May 2022. Criminal career Cárdenas was first arrested in 1995 in Mexico on charges of organized crime and drug trafficking and spent 11 years in prison. While incarcerated in the 'Cereso II' prison in Matamoros, Mario Cárdenas continued to organize the shipment of large amounts of cocaine and marijuana into the U.S. from an automobile body repair shop within the prison walls, having his sentence increased in 2003. While in prison, Mario was also known for holding large parties, inviting prostitutes, organized gambling rings for horse races and cockfights, and having all sort of commodities. He was then transferred to 'Puente Grande', a maximum security prison and after serving an 11-year sentence he was released in 2007 and rejoined the Gulf Cartel. Arrest Cárdenas Guillén, wearing a black bullet-proof vest and flanked by two ski-masked marines, was presented on national television on 4 September 2012. According to reports issued by the Mexican Navy, Cárdenas Guillén was arrested a day before in the city of Altamira, Tamaulipas. At the time of his arrest, Cárdenas Guillén was carrying a rifle in front of a building entrance, along with $10,000 in cash, radiocommunication equipment, ammunition, several credit cards, and four envelopes containing cocaine. The arrest of Mario was one of the "highest-profile arrests in months" and a powerful blow to the