Prison break - Mexican gang moves operations outside US jails

The Mexican Mafia is the oldest prison gang in the United States. Originally it consisted of young Mexican-American gang members, who organised in a Californian prison in 1957. Its name was chosen in imitation of Italian-American Cosa Nostra groups. Also called "La Eme" (the Spanish phonetic for the letter M), members of the Mexican Mafia largely hail from the barrios of eastern Los Angeles.

Originally a self-protection racket, the group expanded its activities to include drug trafficking and extortionate debt collection. Inside prisons, the Mexican Mafia usually victimises African-American and Caucasian inmates, rather than Mexicans, although it exacts violent retribution on those who become police informants.

According to FBI memos from the 1970s, obtained through the Freedom of Information Act: "The Mexican Mafia is only one of the many prison groups that are violently demonstrating their powers, both within penal institutions and on the street. The Mexican Mafia's plans on the street include the takeover of drugs in California." The events of the past 30 years demonstrate a concerted effort by the Mexican Mafia to carry out those plans.

The level of threat posed by the Mexican Mafia is therefore high in southern California, the southwestern US and in areas where local drug trafficking is controlled by Hispanic gangs.

Image: US Immigration and Customs Enforcement officers in Los Angeles check a tattoo on a suspected gang member's back to log any identifiable gang affiliation in 2008. Mexican Mafia members are distinguished by their many tattoos, most notably a black hand on their chest called "the black hand of death". (PA photos) 210 of 3,830 words