More sniper speculation, since you're probably not getting enough from TV:
- The attacks are completely calculated, and there is very little element of thrill-seeking to the killings. They are designed to create maximum terror for the public, not to satisfy the killer's bloodlust. If this were someone who decided to play a video game for real, he would have fretted for days or weeks before shooting his first victim, and then probably retreated in fear for a week or two before the desire to regain the thrill took hold. I would expect this type of killer to increase the rate of killing until he got careless trying to shoot too many people in one day, which would lead to his arrest or death. But this guy (sorry for the sexist assumption) did his big killing spree at the beginning to get attention, not thrills, and has spaced out the killings ever since to extend the terror and minimize his chances of being caught.
- The sniper is a terrorist. I don't know if he's domestic or foreign, part of some group like a right-wing militia or al Qaeda or acting on his own, or if he has any coherent political agenda. But I'm sure that his main goal is to spread terror throughout the population, which I think is the best definition of a terrorist. He had nothing against any of his victims--his real targets are the millions in the area who are scared to go outside or buy gas.
- The cops have become much too predictable with their dragnets following the shootings. The sniper could easily use this against them. Cars backed up for miles on freeways are sitting ducks. Imagine, for example, the sniper driving away from his latest shooting, parked in the middle lane of the highway with thousands of others. He pretends to have car trouble, out of gas maybe, grabs a gas can from the trunk, and starts walking for the nearest exit. Five minutes later he blows up his car by remote control, starting a fire in the middle of the traffic jam. Okay, I've scared myself now.