I lived in Lansing, MI for 18+ years. My parents still live in Lansing. It’s safe to say that I was concerned when I heard about gang violence happening not far from where they live.
But… what concerned me even more was the utter silence coming from city officials in regards to giving information about what happened.
At the meeting I sternly told Mayor Benerno that me and my neighbors had a right to know in general terms what happened. He talked about the importance of keeping details under wraps. I said we should have access to the original police report at the very least. I was told citizens don’t have a right to that.
People are empowered when they are provided the information they need. Silence breeds fear and distrust.
So there is silence coming from city officials, what does this mean? Was the gang violence worse then what was seen? Did something happen with the gang violence that city officials don’t want folks to know about?
Oatmeal Stout - Justin Thorp's blog 
I agree that, at a bare minimum, they are obligated to share that police report.
That said, I would guess that they don’t want to “show their hand” until they have arrested suspects, ongoing investigation, blah blah blah.