Excelsior ran an article today with the title, "Cholos shoot a pregnant woman." "Cholos" is a derogatory slang term used to refer to poor kids who dress with a hip-hop style. It's milder and more common than any American racial slur, but it's clearly derogatory, and it's not a word I've ever seen before in such a context here.
On a related note, I've also noticed that Mexican soap operas have begun sprinkling mildly offensive words into the dialogues. Gancho al Corazón (no relation to this blog) has used the words "naco" and "wey" a handful of times in the last two or three weeks, and I don't remember ever hearing them before, either in this telenovela or any other.