I'm and avid reader of more than a few law blogs.
The general consensus on the States case against the police officers is that it's been a total mess. This seemed like the likely outcome a few weeks ago. A wiser or defter prosecutor might have been able to secure some kind of conviction but it was never going to come from the guys they had behind the wheel.
It doesn't appear that the prosecutors threw the case to get the cops off. The prosecutors made many enemies in the force over the way they tried to coerce testimony.