I’ll give you an example, although I’m not leaning in this theory. Two years ago a jogger was attacked and murdered in my hometown. It was a very rural area, and there was little reason for someone who didn’t live in the community to be involved. When the case was solved, via DNA, it turned out the suspect was a delivery driver who made deliveries in the area during the week, but lived a couple towns over. On the day of the killing (while off work), he returned to the area, pulled up the road from where the jogger was running, and waited for her to run by. He pulled her into the woods, and beat her to death. There is no evidence they ever met, although he may have seen her jogging previously, while he was on the job, making his deliveries in that town.