How do you distinguish between "throwing this trial" and "carrying on a prosecution with no evidence to support the charge"?
It may simply be a situation where they're trying their best but they just don't have the facts on their side. (As the saying goes, you just can't polish a turd.)
I can't. However, I prefer to think the prosecution is smart enough not to do the latter.
If they had'nt charged Z, there'd have been riots from Miami to Chicago the way the professional agitators were pushing this.