Frankly, from what I understand, there is nothing much you can do from your side as the entire matter is now in the hands of the authorities. I do not know if you would be able to cancel your sponsorship at this stage but I doubt it very much. Just let the law takes it course and wait for the outcome. Possibly, the police may inform you of the outcome as you are the sponsor but again such incidents don't take place very often here and as such I am at loss to provide you with any reliable information. However, as Britexpat has suggested, do inform her embassy with a copy of her passport and may be they would be able to guide you better on this matter.