You've heard of the Bloods and the Crips, but now there's a new gang. It's called MS-13 and the FBI says it's the fastest growing and most dangerous of the nation's street gangs.

Mara Salvatrucha, more commonly known as MS-13, has roots in El Salvador and other parts of Central America. In the last decade, the gang has expanded to 10,000 members in this country in 33 states and 40,000 members south of the border.

MS-13 members are known for elaborate tattoos and body art -- and ruthless violence.

Buffalo police issued a warning to all residents Wednesday night, that MS-13 could be planning initiation activities. The warning involves gang members rear-ending motorists and then robbing the driver... or worse... when they exit the vehicle.