I'll tell you something else, just speculating this morning, chain smoking and worried to no end. I manage a shopping center right by this PG county shooting and go there often. But a well-planned sniper attack would take into account the always-present problem of different police jurisdictions. Cops are known to be protective of "their" cases, often causing investigations to go awry. So far, there's been shootings in four jurisdictions in this state (one in DC) and hey, let me say it now, I'm not overly impressed with the police in this state, no much their being "politically corrected" into non-action in this liberal hell of a social experiment.
It's hinky, nothing less. This has all the earmarks of a professional action, not a nut case reacting with emotion rather than logic. Someone is carrying out this "attack" very logically.