Same here, not judging, just guessing. If Dad were in the picture he'd be in the article. Also, if Dad were in the picture this would never have happened, since predators are often discouraged by protective males in intact families. This isn't his first attack on her. I suspect he was emboldened by her lack of father and brother. But -- we don't know.
Unfortunately, predators look for weak prey. It's what they do. Protective fathers are always a deterrent.