Being familiar with Springfield back in the day, I would say this was a crime let out to the outlaw community, successfully performed, then done and long forgotten. These types don't chit-chat and they don't make deathbed confessions. The only way this card pops back up is in a cut deck held by law enforcement promising to reduce prison time. And those types have long since gone to jail already if they were going, done their time, got out and then either died, or washed their hands of past lives. The only other component is that other gang in town, the Law. They know, and what they know somehow reflects badly on them.