I have to say, my initial reaction was the same as Simple Man... As you said, you lost touch with this person for 15 years. That's A LOT of time and people do change. I'll give you a tidbit of personal experience from my life, which may or may not apply here.

I was with someone who liked to be in the spotlight and craved attention. Even though she got everything she needed from me in our relationship (so she said), there was just something about the attention from other people that she craved. This led to her leading a dual-life of sorts on Facebook, talking to several other men, giving them each some sort of story that would explain the relationship status, but would paint a picture of trouble in paradise. Something about that damsel in distress scenario triggers something in the male mind where we feel, in a sense, obligated to "save" this person, which only fuels her craving for more attention. In my situation, even though all indications told me that things were great, the other guys in this scenario were hearing how horrible I was, how I was dominating and controlling (which is as far from the truth as you can get) and how unhappy she was. This caused the guys to come on stronger, telling her how they would come "take care of me" and give her the amazing life she deserved. The thing is, that's not what she wanted. She wasn't unhappy with me or our relationship, but having the attention and affection of other men made her feel "validated", like she never thought she was good enough unless she had men telling her she was...

So, I totally understand wanting to "beat the mess" out of someone you've never met, but consider the fact that you really are only getting one side of the story and you may or may not know her motivation behind it and whether any of this is even true.

And if it really has manifested into physical violence, it doesn't take much to leave a red mark of some kind that can be used as evidence to obtain a restraining order... And if she can't, she should take whatever measures are necessary to remove herself from the situation...