Do you believe that DD knew about Sirius being innocent? He believed Harry in PoA, but did he know it from the beginning? I hardly think so, for I can't believe that DD would have let it happen that Sirius sentenced to a lifetime in Azkaban while Wormtail remained free to help the dark lord rise again. He was powerfull enough to at least insist on using Veritaserum on Sirius or something, I guess.
That made me think...apparently, the Death Eaters know about Pettigrew being the traitor, not Black (they said so in OoP). After all, noone seemed surprised at the cemetary scene in GoF...now, we know that a Spy in LV's rows informed DD that he'd finally found out about the Potter's whereabouts. So, wouldn't that spy as well have told him who the traitor was? Apparently he didn't, for reasons I mentioned above. Why?? Or do we possibly know a spy that has a personal grudge against Sirius Black??
