Assignment: The Most Dangerous Gang in America

The United States has long been home to violent gangs, from the Mafia to the Bloods and Crips. But recently, US authorities have warned of the dangers of a transnational, ultra-violent gang with its origins in Central America. The FBI has now opened an office in El Salvador to deal with the threat of Mara Salvatrucha, or MS-13. For Assignment, Maurice Walsh travelled to Washington DC's suburbs and San Salvador to take a look at MS-13, dubbed "The Most Dangerous Gang in America."