Classic violence against women. Most are not solved. Prevention is the cure.
Edit, to add: in the US.
There are over 100k cold cases in the United States alone. New ones every day. Women of every walk of life.
The reality is: any mildly intelligent medium-build man can easily disable, rape, and kill a woman with almost no resistance in a matter of seconds, and without getting caught. Women think they are safe and repeatedly expose themselves to risk. Predators capitalize on this.
There is a pattern, and prevention is possible with a little bit of training.