You could have stopped right there. A trial -and if it ever happens, I doubt it'll go further than a prelim- will do exactly ZERO to quell the clamoring, and in all likelihood, will exacerbate it. Pulling the plug on this GJ was smart. Continuing a nice looooooooong "investigation" is also smart.
Zimmerman does not need a trial to facilitate seeking applicable damages either.
Testimony on the record will make it a near certainty. Let the mob clamor or not clamor. The hangers on will not follow the mob after a trial.