Is there anything I can do to help a friend that is in an abusive relationship?

A friend of mine is in an abusive relationship. Everytime she leaves and says shes done, she goes back. I know I can't force her to leave, but isn't there anyone that can do anything? This man is a registered sex offender, and his violence is now escalating. Shes had a concussion, cuts on her face, I'm afraid for her life.