H.K.
How well does you daughter get along with your live in? Do they have a good relationship or is there some aggrivation there? I was in a similiar situation with my daughterin preschool, not fighting just more aggression then usual. She really disliked my boyfriend, for four years. I noticed a change in behavior after we split. Now I am married to a wonderful man who she adores and there is not aggression issues anymore. Not necessarally the cause for you...but something to think about..kids don't always know how to voice there feelings and act out. She still needs to be held accountable...by grounding if that is what you do...to know that her behavior is not acceptable...encourage her to talk to a teacher or councilor or even the principal about behaviors of other children to resolve the issue of bullying if that is what is going on..this is the oppurtunity to teach her the right way to deal with situations.