Oh, they've head of them. They're just lying to serve an agenda. But as usual, all the lying is backfiring.
MSNBC is most certainly lying. It is a propaganda organ for the Communist Party USA, wearing the mask of the late Democratic Party.
Here is an article from 2012 listing MS-13 by name.
Is never still longer than 5 or 6 years?
http://www.msnbc.com/now-with-alex-wagner/top-6-things-i-learned-in-nh