When the Mara Salvatrucha finally did join the La EME — they began using the number 13 as part of their gang name. M is the 13th letter of the alphabet and using the number 13 is the signal that your gang has accepted the rules and protection of this prison gang.

Like the other “sureños” — a term referring to Latino gangs from the southern half of the state of California — Mara Salvatrucha began adding the number 13 to their name, their graffiti and even their tattoos. This is a signal to other US Latino gangs that in the California prison system the mexican mafia will back them up.

In Central America the custom persists but many local gang members there don’t know what the 13 means. The Chicano Mexican Mafia has no influence in prisons there. The kids just know that they always use the number because that is the way it is done in Los Angeles.