Some thoughts:
1. This case has gotten a lot of attention in 2 weeks. It has involved multiple LE agencies. But I get the sense that they haven't made much progress. I get the sense that the perpetrator did not leave behind any obvious clues.
2. The perpetrator could have fixated on HB. If so, had he not tried to contact her before? I would think so. It is not obvious that he did, though. No mention of a strange person on campus. No mention of an inappropriate FB overture.
3. The perpetrator could have targeted HB at random. She might have been in the wrong place at the wrong time . . . and just happened to catch his attention. It certainly has happened before.
4. This crime took a litle bit of planning -- but perhaps not all that much. He could have followed HB home at some point. He then finds a vantage point from which to watch her. (He could have pretended to be just a "hunter" in the woods.) When he thinks she is alone, he strikes. He forces her, perhaps at knife-point, to hike to his nearby car. He puts her in the trunk, gags her, and ties her hands and feet. He slips out of the area quietly. He could be on the road in 10 minutes. By the time LE begins to search, the perp is nowhere to be seen.
5. HB's personal items. I imagine he didn't want to be caught with them. So, he got rid of them quickly. Cell phone? Toss it in the ditch! Purse? Toss it in the weeds!
He might have thought that nobody would notice the items, as long he didn't leave them in a pile in one place. 6. Finally, he could have taken HB to a remote location, assaulted her, killed and buried her. Out in the deep woods somewhere, maybe. If the perpetrator is not local -- though, I suppose, he could've lived in the area at one time -- it'll be hard to identify and apprehend him. He might be 20, 40, 100 miles away, never to return.
Grim, I know.
