As to technical ability presuming the distance is about 100 yards or maybe less I would expect several million people would have the technical ability to hit a target the size of a human torso at 100 yards. Just about anyone could with a little practice be able to accomplish this. As the distance goes up the difficulty of the shot increases exponentially. With a year of training I would expect a large number of people could with optical sights make a 500 yard shot on a human torso sized target with a high degree of reliability. If the training was intensive a month would be more than sufficient.
Stay well - Stay saf3e - Stay armed - Yorktown
What we must be asking ourselves is, "what kind of person WOULD coldly shoot a wide spectrum of complete strangers, and what would be their objective?". I can only conclude that the shooter(s) wants to create chaos and terror by making everyone in the area scared to death to come out of their houses, thereby shutting down local society. Now that there has been a school shooting, many parents will refuse to allow their kids to go to school. I don't blame them a bit either. The wide variety of victims and the suburban settings would serve to terrify almost every sector of society. Lawn mowers. Soccer moms. ANY moms. Hispanics. Whites, blacks.
Although it would be premature to pin this on Islamists at this point, it sure stinks of someone who hates America and is actively trying to bring it down, hoping others will join in the attack...that points to either Islam or the DNC, or maybe some of the thousands of raging sign-bearers we saw over the weekend. I'm betting on Islam.