Well done, as you show the system works. Are you saying that because some racist, bigotted and basicly stupid and some criminal members of the legal profession have attempted to railroad innocent people, the death penalty for truly evil persons should not be allowed. As science and investigation techniques progress (beyond a doubt) is provable. The past has been brutal and has helped us get to the real proof of criminal actions. As long as good people stand up for the equal rights of all, truly evil persons can be removed and put to death.
In short, the system certainly does not work. In the above case, one could reasonably conclude that this individual should not have been put to death - even the prosecuting attorney seems to agree with this position. It is a very arguable point as to whether the system is working!