the weakest point of the movie for me...
...was not the double jeopardy thing everyone here is harping on (I loved the ending - I really needed Hopkins's character to suffer after everything that transpired, and can't say I particularly care for legal technicalities (at least not in this case, since it all seems plausible enough to me)). It was Nunally's suicide. I mean, think about it: their entire case now hinged on that second bullet, but in real life what would have been the chances of a man killing himself over that verdict? And right there in court, no less.
Sorry, I just don't see it happening, no matter how much he loved her (and let's not forget she was still alive at the time - I mean, the almost total stranger Willy read poetry to her at the hospital, but Nunally didn't even visit??), or how much pain he was in. That entire incident struck me as extremely bizarre and out of place.
Crawford getting off could have set him on the path of revenge, yes, but not suicide.