Peterson was convicted on circumstantial evidence as well. No one witnessed the murder, nor did they witness him putting her body in the lake. There was evidence pointing to his guilt - strong evidence because of the cement etc., but how do we really know he did it? Maybe it was a co worker, or some other person who worked around cement. He had motive. He was the last to be with her. He would have received some type of reward through her death - just like C. Anthony. He was found guilty beyond a "reasonable" doubt, just as Anthony should have been.
There is no reason to celebrate our judicial system right now. An uninformed jury is a flaw. Circumstantial evidence is all we've had to work with in millions of cases since this country's founding. If we do away with it like the jury did yesterday, no one will ever be convicted of any crime without a video clip.
There was evidence pointing to his guilt -
“strong evidence because of the cement etc”
Which is what differentiates the Anthony case from Peterson’s.