Well, I mean, there are people out there who won't take "Please, my daughter is only fourteen and I would appreciate if you would leave her alone" for an answer. I can't blame the mom, if it WAS the mom, for feeling like she has to threaten legal action.
On the other hand, that kid had better be getting the spanking of her life, and total grounding.
On the other other hand (just call me Ganesha, right?), there are some people on the 'net who go for drama, and would do such a thing just to stir up excitement. It isn't pleasant to think about, but they are out there. ANother reason to just sit tight and leave it alone... and check your playmates more carefully, possibly.