Addendum, a Little Bit Later:
PoliticalProf agrees. A snippet from his response to a reader’s question:
Oh, it seems to me that the prosecutor had no desire to bring charges in this case, and so emphasized the parts of the evidence that tended to complicate and/or exonerate the officer’s actions, while de-emphasizing or muddying evidence that worked against the officer.
So no indictment is no surprise.