I have to disagree with you because of the possibility of human error, as sometimes happens in judicial practice.
Let me remind you that several innocent people were convicted for Chikatilo's crimes because of the pressure of their superiors on the detectives. Under pressure, suspects often take the blame for crimes not committed.
If the real perpetrator is found, the innocent can be exonerated, but the innocents who are shot cannot be returned to their relatives!

Thank you for the detailed presentation of your point of view on the death penalty!