IMHO if they say the cop is guilty and they are going to seek the death penalty for him the town is still going to riot and destroy just because. They will just call it a celebration though.
if they return that verdict I would expect a mass resignation of police officers across the country. Why would they put their life on the line for a district who would destroy them just to pacify a group of domestic terrorists
Grand juries don't return verdicts (guilt or non-guilt). They only return an indictment (True Bill) or a non-indictment (No True Bill). An indictment merely means that the grand jury believes that sufficient evidence exists to constitute probable cause that a crime was committed. That indictment then leads to arrest and prosecution of the accused, who will then face a trial by petit jury.