In the suburbs of Washington, D.C., police in once-quiet neighborhoods are waging war against the Central American gang Mara Salvatrucha 13, or MS-13.
Roughly translated, the gang's name means "Salvadoran gang, fear us."
"MS-13's more prone to violence — anything from robberies to shootings to cuttings, machete cuttings, people being beaten with baseball bats, pipes," said Sgt. George Norris of the Prince George's County Police Department in Maryland.
"A lot of rapes," he added, "especially of younger females, Latino females."
Norris estimates there are now 1,000 MS-13 gang members in his county alone. With an estimated 10,000 members in 33 states, the FBI says the gang is now spreading from the nation's cities into the suburbs.
Residents in neatly manicured northern Virginia are scared. Brenda Paz, a 17-year-old pregnant girl there, was nearly beheaded in 2003 after the gang learned she was helping police in a murder investigation.
"When I moved here," a local resident said, "I never heard of any gang activities. I never heard of people having their fingers chopped off."
MS-13's members mostly are illegal immigrants from Central America, and they are suspected of hundreds of murders and thousands of assaults.
"We're approaching them as we did the mafia," said Robert Clifford of the FBI's National Gang Task Force, "identifying the criminal enterprise, identifying the leadership, their lines of communication, their financing and attacking the infrastructure."
MS-13 is not only violent, it is highly organized. And this has set off alarm bells among law enforcement.
"Unfortunately, MS-13 is very big in countersurveillance," Norris said. "They do watch for the police. They have pictures of a lot of us. They have videotape of a lot of us. While we're doing surveillance on them, they're doing surveillance on us. In one instance, just last week, we did a search warrant on an MS member's house and got digital photographs of me."
"Jose," 28, an MS-13 member who asked not to be identified for fear of being killed, told ABC News he has stabbed people "a lot of times," perhaps 10 to 15. He also has shot at people and tried to kill in the name of MS-13.
"We don't pull a gun out just to scare you," Jose said. "If we pull a gun out, we gonna shoot you."
However, MS-13 draws headlines for its preferred weapon of fear, the machete.
"You know, guns are real loud," Jose said. "So what they do is then they use machetes now because it makes no noise at all. By the time, let's say, you injure somebody with a machete, kill them or whatever, by the time police get there, you know, you're gone. You're way gone."
MS-13 members embrace violence because it is all they know, Jose said. Most come from the tiny Central American nation of El Salvador. It is there that they first witnessed unspeakable violence during its brutal civil war.
"Used to see bodies left and right," he said. "Headless corpse -- I mean, you know, people that were mutilated. All that kind of stuff. Tortured before they got murdered. And you just grew up with that mentality."
When civil war gripped El Salvador in the 1980s, tens of thousands fled to Los Angeles seeking safety. They settled in some of L.A.'s toughest neighborhoods and were confronted by violent street gangs. The response was the formation of an even more violent street gang, MS-13.