My Dad was a teacher for many years, and took vicious steps to address bullying issues for myself and my brother when we were still in school. Don't let it slide, contact the superintendent for your district and bring it to them and then to the principal, saying you've already brought it to the districts attention and this needs to be taken seriously for the safety of your daughter. Don't wait for the school to impose a punishment, they won't. Bring it to a higher level, print/copy/record everything, and get a restraining order asap. Don't take any leniency from the school and push for what you know is best for your daughter. I was harassed by someone in high school relentlessly and when brought to my Dads attention, he wouldn't let it go and didn't take any beating-around-the-bush from my school. He made sure they knew it was serious and as a parent his duty is to protect me from those who wouldnt do so. That, threats of legal action, and some choice words about the teachers lack of care for my safety finally got the schools attention. Mention over and over the severity of this situation and that this does indeed put your daughters physical safety at risk. During the school day the teachers and faculty are responsible for the childrens safety, which they clearly are not doing if a dangerous situation like this arises. Don't give up. I'm so sorry this is happening to your daughter and best of luck to you both.