two23: I think you are exactly right. The sniper does not have to operate under any of the usual rules for a sniper. He is not constrained to trying for high value targets or even specific targets. It is essentially a free fire zone for him and he can pick and choose whatever works best for his own survival.
the gillman@blacklagoon.com: I hadn't thought of a decoy vehicle but I tend to doubt it. It violates the most important operational rule this killer has used KISS. Coordinating two vehicles is probably more trouble than it is worth.
SauronOfMordor: I agree that a .30 cal weapon would be more likely to lead to discovery. I tend to think of that as another arguement in favor of a terrorist rather than a nut. A nut would be more interested in killing, a terrorist in causing terror.
All: I think the question of two people or one is significant in answering whether we are dealing with the mentally deranged or a terrorist action. I know of several examples of nuts who were highly organized when commiting there crimes (i.e. unambomber, citizen X in the old soviet union, etc.) I am unaware of any multi person nut killings that display a similiar concern for escape. Usually the pattern is to go out in a blaze of glory. When two or more people are involved and planning is evident. You are usually looking at rational people with a clear motive. Gang and Mafia killings are the only examples that come to mind. These are usually planned so that the perps can get away.