Fair point. And a good criticism to my concept is that if a person is falsely convicted of one heinous crime, then escapes and is accused of some other heinous

Fair point. And a good criticism to my concept is that if a person is falsely convicted of one heinous crime, then escapes and is accused of some other heinous crime, the original conviction would likely be used as evidence towards motive and means. I'm not sure of a good solution to that problem, although it would certainly shrink the number of executions of innocent people, it would not completely eliminate them.