The guy is pretty brazen to have murdered/abducted two girls in broad daylight in a relatively public place. He had no way of knowing if other people would appear on the bridge or the trails below. The weather was mild and school was out for the day increasing the likelihood of other hikers in the area.
We preach to children not to travel alone, to stay in pairs (or more) to increase the possibility of staying safe. Pairs aren't even safe anymore. Maybe we need to start teaching children that they might as well yell and scream as loud as they can, even if they are being threatened and told to stay quiet because in all honesty the person is probably going to kill them anyhow even if they are quiet so they might as well make a lot of noise. Sad reality for the next few generations of kids.