I had a similar feeling - but then figured that's what they were going for .... Real life doesn't generally get closure either.
Yes--I think they were going to give you as much closure as you were going to get. Nothing is 100 percent certain in life.
Guilt? Innocence? Our justice system is filled with uncertainty. "Reasonable Doubt". A hung jury.
We don't always know for sure. Sometimes a killer goes free and sometimes an innocent man hangs.
Just like life. What will tomorrow bring? Or the next day? None of us really know or ever have that sort of "ending" to our story. That only ends when we die, and then the questions of the events and people left in our life's wake are for others to interpret and decide.
Ultimately the story was more about an event like this--the whole process and system and its effects on people's lives.
I don't know that I've really seen that story told so well before.