A lot of evidence apparently has been gathered. However, evidence by itself is not much good unless you have someone to match it to. That takes things like fingerprints and DNA. I suspect they have (and have had) a suspect(s) in mind for awhile now. But they cant quite link him to the crime just yet. The cat and mouse game being played is to more than likely unnerve him into making a mistake or confessing. What they are waiting on are the final results from the crime scene forensics to come back. Then they can make a move.
There is not just money in that area, but old money that has a great deal of influence attached to it. Some of the families in that area go back hundreds of years and have been very instrumental in developing not only Charlottesville but the University of Virginia itself. If LE suspects someone associated with a family such as that, they will have only one chance to build an airtight case prior to an arrest. The finest and most expensive legal counsel in the country would be available to such families. Keep in mind the $150 K reward is not exactly bringing people out in droves. It may be that whoever is involved in Morgans death comes from a family where that is considered to be not a lot of money.
I am curious as to why suddenly Federal Law Enforcement such as the FBI has been brought in. Local law enforcement can at any time request the assistance of the FBI in any matter and for any reason. It was announced at the beginning that the FBI was working the case with the VSP. But then you never heard another word about them. And now you do? I wonder why? Could it be that the suspect is perhaps in this country on an educational visa and not a USA citizen? Just thinking out loud here, thats all. They could be invoking the FBI just to rattle the suspect too.
The biking clubs in the area are very diverse. Here is a link to one of the largest. Off road is much more popular than conventional biking. UVA has a cycling club as does VT and just about all the other colleges as well. Id guess they are looking at off road riders for clues.
http://cambc.org/