RE: A person must face consequences

Like you nailed it and this snippet below said it all

Suppose one person committed a murder and, after the murder, the person felt guilty and became a better person. So, is it okay to leave him? If he remains unpunished because he became a better person later, everyone has the right to murder one person and become better after that.

Crimes becomes a normal thing for everyone if there's no accountability for what's done in the past that destroyed people's lives (emphasis on lives involved).
It may be overlooked if it's just something that doesn't affect people's lives or that affected his/her life alone or something