From Day One I had a strong feeling that this was more than just a random shooting. At first I thought maybe the guy was targeting a police officer who had arrested him.
The initial public statements from the police also seemed to support a "targeted shooting" theory. They warned that the culprit was on the loose, but also said the public wasn't in danger. That's a strange thing to say, but it does make sense if they knew the guy wasn't running around shooting at random targets.
On day one I told my best friend either cop on cop or cop banging somebody's wife. We have many police acquaintances, and see both cop-on-cop pissing contests and rampant adultery often.