Aren't you missing the point slightly? And assuming the result before it's known ?
'Let the criminals prove their innocence'
If they're criminals then by definition, they're not innocent.
If they're innocent on the other hand, then we don't want to punish them. Any law system will be less than perfect, as it's necessarily going to be run by people, and we're non of us perfect.
It boils down to what are you more interested in avoiding, false negatives (criminals being let off) or false positives (innocent folk being punished).
Are you the sort of person who's more interested in revenge and seeing someone killed, or in letting decent folk like we like to think of ourselves being free to get on with our lives in reasonable safety.
In answer to another e-mail from lower down the page, but on the same subject, I believe that if the death penalty doesn't deter a potential mass murderer then nothing will, for the simple reason that they don't believe they'll ever get caught (until of course they do get caught.)
Also, if you're not the sort of person who commits serious violence, then why are you so keen on seeing others, even criminals, tortured ?

Yours Stevie Hair