But...but...her extensive professional training tells her that her life is in grave danger whenever she cannot see a citizen's hands, and her life will end in a split second if he takes his hands out of his pockets when she orders him to...
In all seriousness, I can easily imagine 30-60% of jurors believing that he deserved it for running/resisting, or that it's wrong to send a cop to prison for doing her job, or even being afraid of police reprisal if they vote to convict, but a unanimous acquittal tells me that there was something seriously wrong with the case. My first guess is that the prosecutor didn't want a conviction, he just wanted to look like he tried to do his job.