His supporters have had a long time to devise possible, alternate scenarios in an attempt to prove Scott's innocence. Given enough time many of us could come up with a story to get us out of trouble or lesson the blow. If these theories were plausible, they would have either been introduced in the trial or would have been given more consideration, when they were introduced. He was well represented, so it wasn't like his defense attorneys were inexperienced, underpaid, public defenders. His lawyers didn't introduce some of the theories we're now hearing, because they've either been newly invented or they didn't consider them credible. I watched the original trial & have no doubt he did it. The idea that Amber Frye did it is ridiculous, IMO. If she did it to have Scott to herself, she wouldn't have come forward making him the prime suspect. His supporters are throwing everything they can come up with out there hoping something will stick.
As for the Casey Anthony trial, I think it's a tragedy that she walked away scot-free. I watched most of Scott's trial & a lot of hers & think there was as much evidence against Scott as there was against her. Both of them should be in prison for life or on death row.