This is HUGE. It's exceptionally difficult to lie about this type of thing and be consistent about it. Yet after 4 hours of questioning without an attorney and reenacting the event on video, the first prosecutor decided there was no evidence to prosecute. On top of it his statements just happened to coincide with information as well as eyewitness testimony he could not possible have known existed.
On top of it, so far as I have seen, every bit of the story makes sense and "fits". People just hate it because they don't want to believe it, and therefore convince themselves it's unbelievable.
This is kinda where I am. Based on the information available, it appears probable that it may well have been a justified shooting. (Now if the prosecutor has more evidence that could change things).
As an aside: the media's reporting has been horrible. My initial understanding was that someone who outweighed another by over 100 lbs had shot him, then not even been taken in for questioning but instead released with his gun. And we now know all of the previous to be false. (This isn't even going into the photos and the NBC editing etc). A huge amount of this controversy has been whipped up by the media, apparently on the basis that lynch mobs buy newspapers.