A member of the "Mara Salvatrucha" gang flashes the sign of his gang in San Salvador in 2006. (Yuri Cortez/AFP/Getty Images)

Here‘s what you need to know about the gang whose motto — “rape, control, kill” — has created fear in Washington and nationwide.

Mara Salvatrucha means “Salvadorian gang” and was formed in Los Angeles in the 1980s by immigrants from war-torn El Salvador.

— The “13” is believed by experts to come from the 13th letter of the alphabet: M for “Mara.”

— MS-13 is made up of “cliques” with names such as the Sailors, Normandy, Peajes, Uniones and Fultons.

— They work through a partnership called “La Hermandad,” or “the Brotherhood”across the District, Maryland and Virginia.

— The gang spread beyond Los Angeles and California in response to anti-gang efforts and a demand for low-skilled workers across America. Many relocated to the Washington area, including Northern Virginia.

— MS-13 is believed to have between 1,500 and 3,000 members.

— Many are between 16 and 18 years old.

— Locally, the gang has been linked to shootings, baseball bat beatings, the stabbing of a pregnant teenager who was a federal witness, and the removal of four fingers from a 16-year-old boy’s hands using a machete.

More on MS-13:

MS-13 gang is branching into underage prostitution, authorities say

The antisocial side of social media helps police track gangs

11 accused of gang crimes in the D.C. area

Gang members describe life inside MS-13

First MS-13 trial reveals mysterious gang hierarchy

The ABCs of fighting MS-13

FBI agent: MS-13 gang out to ‘kill, rape and control’

View Photo Gallery: The Mara Salvatrucha gang, the transnational gang known more colloquially as MS-13, is involved in criminal activities in most parts of Latin America, as well as the United States. The gang originated in Los Angeles and spread from there, and now has a large presence in Fairfax and Prince George’s counties.