So, as just posted, the FBI’s exhaustive study shows a 1 percent, not 50 percent, false positive rate. It’s 99 to 1 the reported match is a true match.
So where would RA be without that cartridge?
BG is walking over the bridge, nearing the girls. RA put himself at the far end of the bridge, looking at fish. That was his closest approach to where BG is when we see him. Close, but not close enough to innocently account for him actually being the man in the picture on the south end of the bridge walking up to the girls. Bad luck, or bad alibi?
Even RA didn’t see BG go by him. Bad alibi?
LE is sure that the man in the picture is Mr. “Down the Hill,” the kidnapper and most likely killer of the girls. The kidnapping audio and the pictures are that close in time.
RA is the same size as BG and was dressed a lot like him. Bad luck.
Nobody saw two similarly dressed shortish middle aged men on the trail. That would have been a basis for doubt, but RA is unlucky. People saw one and only one BG-looking man arrive and go down the trail when RA says he did. Bad luck.
Nobody saw him leave when and where he says he did. Bad luck.
Nobody saw RA anywhere when the killer would have been in the woods with the girls. Bad luck.
Then there’s that damn bullet, ejected, lying in the leafy carpet between the bodies. 99 to 1 it can only have come from his gun. That was the cherry on the whipped cream on the sundae for me.
Real life never gives you 100 to zero. You don’t wait for that. It’s not reasonable.