After all, it is always the cops fault, right?
Not at all. I am inclined to believe the cops did the right thing because cops usually do the right thing, however this accusation is serious enough that it should not be dismissed out of hand.
If forensics show that everyone was shot with 5.56 ammo, then it becomes harder to believe that bikers shot each other.
If we hear that they were shot with .45s, .38s, 9mm, etc, then we can dismiss this accusation as having no merit.