Need name of this anime/manga or if the anime is not known, an anime/manga similar to it. Help!?

From what I can remember, a girls parents are murdered protecting something, maybe her. She runs away and her parents (or maybe supposedly parents) murderers are hunting her now. If I'm remembering this right the reason her parents were murdered is because they or she alone has some sort of special power or ability, that she didn't know about. Something like that.

I'd be really grateful if anyone could find this anime/manga but if not something similar to it. Thanks!:)