Unfortunately, 999, our laws in the UK do not require 'irrefutable proof' for an accused person to be found guilty, they require that the proof be 'beyond reasonable doubt', and that has resulted in a number of cases where people have been found guilty, only for a miscarriage of justice to have been proved later. Many of the wrongly-convicted have been released and have returned to normal life.......sadly that isn't an option for the surprisingly large number who were wrongly executed.

Lock 'em up, that's what a civilised society does. Throwing the key away is an option for the most serious crimes..