The suspect in this case is a registered sex offender. When the young woman began to work for him, she apparently did not know this. One of her friends commented that he "seemed like a nice guy" as they went to his house. She had not been educated to vet people, men especially, if they are going to be working in a private location with them, such as a house. A simple Google check would have shown her that he was a dangerous sex offender.
The victims are by no means at fault. The blame is squarely on the shoulders of the offender. But we as a society have a share in that blame. Too many times, we teach our young women, through social etiquette, not to be too loud. We teach them to be submissive. We teach them that "fighting" is not for ladies. We teach them that self-defense can be a little violent, and a little scary.
What we should be teaching them is that self-defense is not scary... Not knowing how to defend yourself... THAT IS SCARY!