Come up with an excuse to photograph the injuries. Im a cop and in my expierence the abused party takes it to a point and then fights back. When he/she does the abuser files charges and the victim goes to jail. Without proof of provocation there is really no defense for the victims retaliation. If she can show a pattern of physical abuse shes in the clear. Even if she wont let you photograph the injuries document them for her. Location, severity, type, and approximate time recieved. Even document the story she told you. Trust me it helps. Any questions feel free to ask.