It could have been someone else in the videos and someone else doing it in front of the witnesses. He could have hired a double and dressed them the same then switched... I’m sure he’s 99.9999% guilty btw.
I actually feel a bit silly typing that, but hope you get the point I was making!
Not sure on the specific cases & cba to read up on it now - but you can never be 100% sure they were guilty. Only they themselves can. A confession could technically be false. A cctv image could technically not be them or be faked - just playing massive devils advocate but no crime an outsider...
Another reason you shouldn’t have the death penalty is you cannot ever be 100% sure someone is guilty. You can be 99.999999% sure but never 100%. I challenge you to show me a case where someone is 100% guilty. :)