Retaliation for online bullying?

I was just doing a google search of my little sister's name and some piece of filth from her school used my sister's full name to write the most horrible comments about her in a "live blog" journal that is the first link that comes up when you do the search. I can probably figure out who this person is, and as the older sibling my first instinct is to go there and wring the life right out of this middle school scum, but of course I can't do that. Is there a way to get back at her, or at the very least, get her to remove the actual full name and information (which school, district, etc.)?