Ahem.. If I was one that believed Snape was guilty I would have something rather ironic to say right now...
Well, J.K.R is doing the exact same thing she did in the first book, she led us to believe Snape was the bad guy. I, for one, fell for it, so I'm not falling for it again.
... The opposite might reply that you are falling for the opposite this time, because you believe she would do the same thing again.
It's the exact replica of a scenario I saw on old Bewitched last week.
Now, I don't believe it, but if she would do it, I can see how she could be having a quiet chuckle at us right now...