Los Zetas has the largest turf of any Mexican drugs gang. It was formed in 1999 when Mexican elite commandos ditched the army and joined the Gulf cartel, becoming its armed assassins. Los Zetas began hiring themselves out to other gangs, including the Beltran Leyva group and the Juarez cartel, and eventually split from the Gulf cartel in 2010. At the beginning of 2012 the government went after Los Zetas, announcing that five military bases would be established on its territory. On 9 October 2012 Los Zetas leader Heriberto Lazcano was killed in a firefight on the Texas border. On 14 July his successor, Miguel Angel Trevino Morales, was captured in Nuevo Laredo.
Considered the most powerful of Mexico's gangs, and also among the oldest, the Sinaloa Cartel is run by Joaquin 'Shorty' Guzman. Guzman, then the gang's No 2, had been arrested in Guatemala in 1993 and was sentenced to 20 years in a maximum security jail in Mexico. He escaped in January 2001 by hiding in a laundry trolley after bribing prison guards. Guzman is blamed for breaking the non-aggression between the cartels, sparking a gang war that has killed more than 50,000 people in seven years.
The oldest gang of them all, the Gulf cartel has been weakened by arrests in recent years. After Los Zetas deserted them in 2010, the cartel then split into two groups, Los Metros and Los Rojos, with Los Metros coming out on top. Under the presidency of Felipe Calderon many of its leaders were captured, including Osiel Cardenas Guillen - who took control of the cartel in the 1990s by killing a friend and is currently in prison in Houston - and his brother Mario. Another brother, Antonio (aka Tony Tormenta), was killed in 2010, while in September last year its leader Eduardo Castillo was also arrested. Osiel Cardenas was so powerful he managed to corrupt the commandos sent to kill him, who eventually went on to become Los Zetas.
La Familia/Knights Templar
La Familia was formed in the 1980s, ironically as a vigilante group to eradicate the drugs trade. It gained a reputation for extreme brutality, often co-opting religious symbolism in its murders while simultaneously doing community work to help the poor. A one-time ally of Los Zetas, it eventually turned on its former allies before announcing in November 2010 that it would disband. A month later its spiritual leader Nazario Moreno Gonzalez (aka El Mas Loco) was killed, and in June 2011 its commander Jose de Jesus Mendez was arrested. An offshoot, the Knights Templar, has taken over much of its territory under a former Familia lieutenant Servando Gomez, and is engaged in sporadic conflict with remaining Familia loyalists.
Beltran Leyva Organisation
A faction of the Sinaloa cartel until 2008, in January of that year Alfredo Beltran Leyva, brother of leader Arturo, was arrested, allegedly with the help of Shorty Guzman. It has since formed strategic alliances with Los Zetas to fight the Gulf, Sinaloa and La Familia cartels. Arturo was killed by marines in 2009, while brother Carlos was arrested in January 2010. A fourth brother, Hector, then fought a long battle for control of the organisation with Gerardo Alvarez-Vazquez and the Mexican-American Edgar Valdez Villareal (La Barbie), who was arrested in 2010. Hector Beltran Leyva and Edgar Valdez eventually formed separate groups under the BLO banner.
Tijuana/Arellano Felix Organisation
Formed by a former Sinaloa police officer who established a network with a number of other drugs kingpins, including the Arellano Felix family - seven brothers and four sisters who inherited their uncle's drugs turf after he was arrested in 1989 for killing a DEA Special Agent. Five of the brothers eventually took it over. Of them, Ramon was killed in 2002, another, Benjamin, was arrested and the last involved in the drugs business, Eduardo, was held in Tijuana in 2008. A battle ensued with other gangs for control of the turf, which intensified when a key lieutenant joined forces with the Sinaloa. The AFO is now headed by Fernando Sanchez Arellano, a nephew of the original brothers.
Juarez/Vicente Carillo Fuentes
Originally part of the Sinaloa until it split in 2008. Now controlled by Vicente Carillo Fuentes, brother of the original founder Amado, it is responsible for turning the town of Ciudad Juarez into a bloody battleground and the state of Chihuahua into the deadliest in Mexico as it battles for control of the Texan border with its former allies. In July 2011 Jose Antonio Acosta Hernandez (El Diego), the head of its enforcement arm La Linea, was arrested. He confessed to ordering 1,500 murders and sentenced in the US to four consecutive life terms in 2012.