Yes, the difficulty arises that every person who is arrested is innocent in the eyes of the law...until proven guilty. Every person shot by the police is just as innocent. And then we have a bunch of salesmen (prosecutors, the state etc.) tasked with selling the concept of their guilt. The defence are no less salesmen and they are tasked with selling the concept of their innocence. It has been like this since the ancient Greeks. Yay rhetoric! Were the system truly fair, both sides would be engaged in solidifying innocence. That a successful prosecutor can make more money when they head up the food chain or leave for private practice pretty well guarantees an unfair result when there is a lack of funding for a really skilled defence.

Gerald Bull designed his "super gun" to put payloads into orbit. He approached the US government with the idea and they rejected it as a launch method but wanted a weapon. Disgusted and disillusioned (he was apparently treated very poorly) his response was to create a truly powerful weapon. Iraq hired him to build one for them. The Mossad killed him in Belgium, a country that exports arms all over the world. It's important to remember that the US military has done this with a number of inventions. The guy who invented the x-ray laser had wanted to use it for medical purposes; excising tumours etc. The US military classified it and now it's a weapon. Another Canadian invented polymorphic encryption for secure banking and corporate communications...US military classified his work and as far as I know he can't even talk about it with his peers.