I would argue that Kant is wrong in tis context because he is treating the person being executed as a means to an end (satisfying justice, eliminating blood guilt, etc.).
Yeah, those aren't arguments at all, they're simply stated beliefs...
How did this guy get to be influential?
What if one gets framed for murder and the law can't see it right? That's a problem.
I think we should only enact this when there is definite evidence to support the claim.
Like finger prints, live video capture (probably not edited with effects?), and DNA testing?