It seems that they just want to sit back waiting for one more of these to happen, as if the police are defenseless against this.
How about using some of that great spy technology we have to put cameras into the wooded areas near shopping centers, etc. until this guy is caught?
The only way you're going to catch him is for a "witness" (electronic or human) to see him setting up for a kill and report it.
So, you just deploy about 10,000 cameras with battery and wireless broadcast to the woods in "risk" areas, and watch and wait.
And, BTW, don't tell anyone you're doing this. Just do it. If it makes the press, the sniper will find another city.