This kind of scenario happens occasionally in New York City when police officers kill someone in a case that gets a lot of bad publicity.
1. The prosecutor files a murder charge against the police officer.
2. The police officer opts for a trial before a judge instead of a jury.
3. The judge -- who decides the case based only on the facts and on a strict application of the law -- hands down an acquittal.
In most cases, the same @ssholes who clamored for a murder charge at the beginning of the case often criticize the prosecutor for filing such a serious charge in the first place. This "change of heart" usually happens about two-thirds of the way through the trial, when it becomes obvious to anyone who knows anything about the case that there's no way in hell a murder charge is going to stand up under any legal scrutiny.
We had a judge in lieu of jury trial here...Black on black....Justice was NOT served because the guy with the knife went hunting for the “unarmed” dude and stabbed him to death.....4 or 5 times. It was a farce. Someone knew someone in this case...I’m certain...just plain dirty.