Antonio Cardenas Guillen rose to the top of the Gulf Cartel following the extradition of his brother Osiel to the United States in 2007. Osiel is now in a United States prison serving time for drug trafficking and threatening a U.S. law enforcement officer. Before his death, Tony Tormenta was considered the strategist and money-man of the operation while his associate, Jorge Eduardo Costilla Sanchez, alias "El Coss," was thought of as the muscle. Cardenas controlled the cartel’s most lucrative "plaza," or drug trafficking corridor, Matamoros-Brownsville, Texas, for years.
Cardenas was indicted in 2008 in the federal district of Washington DC. The U.S. offered a $5 million reward for information leading to his capture.