that any given cop might have had an issue with this guy ...relative to a that booking for whatever crime...which did not lead to the guys being found Guilty and being imprisoned.
Im not saying his having been booked justified his shooting simply looking at possible motives FOR the shooting.
Why look for conspiracy and a premeditated murder when you have zero reason to do so, and it appears to have happened in a scenario that couldn’t have been a set up?
It was probably just the usual.