This is sure a scary situation for your family! Have you sat down with your daughter and asked why she doesn't want to move? Usually students will respond it is becasue of their friends or they "know" the school. Does your daughter feel afraid of school and not want to attend? How is she "avoiding" encountering the problems that have led to the killings?
I would certainly arm myself with information. Check with the guidance staff and principal of your school. Even consult with your daughter's teachers concerning their perspectives. Does this school have a security officer? (Many schools have enlisted the support of the local police who have provided officers for schools.) If so, give that person a call. Call your school's superintendant and school board representative to see what steps are being taken to protect students. If you are still concerned, ask about transfering to another school.
Sometimes as parents we have to make tough decisions to keep our children safe. Gather information then make your decision.
Have you tried talking with the principal regarding your concerns about the school? He or she should be made aware of any issues with violence or unsafe conditions on campus, and can share what is being done to protect children and address problems.
Additionally, you should talk with the school district about their policies with regards to transferring from one school to another. If your daughter attends a school in the United States, you can use SchoolFinder to find the contact information for the district, as well as to review information about other schools in the district: http://www.education.com/schoolfinder/
If you do decide to switch schools, there are some things you can do to help ease the transition for your daughter. Here are some related resources...