Well since the only evidence you cite to support your position is akin to a friend of a friend, non inclusive of specifics, you must admit it is somewhat difficult to assign any weight to you position.
Take a look at all of the Virginia shootings and how close they are to the highway. Then look at the shootings here in Montgomery County and see how far away from the highways they are. Whoever the shooter is, he is very familiar with the heart of Montgomery County and is most likely a long time resident.