How do you get to the point of being, arrested, tried, and convicted, if you weren't even prese

In part 2 we ask the question how is it possible to be arrested for a crime you didnt commit? Let alone be convicted? We discuss some ways this may happen. Past cases shows us it has happened, but how did they get there? Surely there are safeguards in the legal system. Surely that couldn't happen? This has to be a case of a Mother's blind love, right? It has to be, or is it that thinking the alternate idea of innocent people going to Prison, that innocent people have been killed in the name of justice, is to much of a nightmare to believe, that are minds won't even let us entertain the thought?