Its the "We, the people" meaning we are making decision whether one dies or not based on professional opinions on evidences. That is EXACT how it is, you, even myself is involved, period.
My point is, we shouldn't act like God, leave the death penalty to God, because there is no such thing as 100% perfect conviction even if it is very obvious.
The best way to make sure NO innocent get executed is to never allow any execution regardless.