The prosecutor could have a taped message from Trayvon to Dee Dee along the lines of "I'm going to go find that fat wetback who was watching me and kill him" and he/she would go ahead with the prosecution, and try to keep the defense from getting that evidence.
After the O.J. trial and the Scooter Libby trial, I don't have a lot of faith in the criminal justice system. The State of Florida probably deems preventing rioting (if Zimmerman goes free) more important than some guy getting a fair trial.
Bernie De La Rosa works for Special Prosecutor Angela Corey and is her lead prosecutor in this case.
The threat of rioting is a mere ruse. Anyone who is afraid of that needs to buy themselves a package of diapers.