I've read that Williams was a bit of a self promoter and not totally honest. Movies tend to overlook this stuff. As far as being a convicted killer, things were very different in those days. My late mother who was born in 1922, told me a story about her father, a Spanish American war vet who was a butcher by trade and a drinker and gambler by choice. She saw a man peeking into her window one evening and told her Dad. He immediately grabbed his pistol and took off after the guy. She didn't know what happened, but the guy never came back nor did she ever see him again. While it was illegal to kill people, shooting someone for good reason wasn't frowned upon as badly. People were free to solve a lot of these problems with their fists or guns and the prison time often reflected circumstances.

There wasn't a lawyer hiding behind every tree in those days, and cops were responding to trouble not out looking for it.