If it is linked then it could have been a smokescreen to hide the real reason for the murder. Otherwise is just another crazy person with a too easy access to firearms.

While not the most investigative considering it's fairly new, there is enough context to see an overall pattern emerging. But the readers are left to interpret the pattern mostly on their own. I find this falls in line with hinting at gang influence for the shootings in order for readers to feel comfortable that it has nothing to do with them so it won't happen to them.