"The Mara Salvatrucha (MS-13) is a violent criminal gang operating both in the United States and abroad--namely Central America. MS-13 was formed on the streets of Los Angeles, CA, in the 1980s by refugees who were fleeing civil conflict in El Salvador. It became a transnational gang as MS-13 members who were deported from the United States to Central America helped establish gang ties and spread U.S. gang culture abroad. In the United States, MS-13's structure largely consists of loosely organized cells, or 'cliques,' that each control specific territory. While some have suggested that the size of MS-13 has grown in the United States, since at least 2005 law enforcement officials have consistently cited its membership to be around 10,000. Domestically, MS-13 has been involved in local crimes including extortion, drug distribution, prostitution, robbery, and murder, as well as transnational illicit activity such as drug trafficking and human smuggling and trafficking. The gang is known for its particularly violent criminality, which has been demonstrated in a reported uptick in violent homicides attributed to MS-13 in certain locales."
CRS Report for Congress, R45292