n the legal reasoning that led to the acquittal of Thug Brelo.

I would not say the reasoning is wrong. If the charge was that Brelo individually was the killer of the two passengers, indeed that can't be proved. Perhaps it was the wrong charge. Would "attempted murder" have been provable?

Is it generally the case that when several shooters hit a person who is killed by their bullets, none of them can be convicted of murder?