RO: And I know that I am going to be accused of being heartless. But to illustrate. Let's say that your a grown adult and you happen to move back and live with your parents after you got out of prison for murdering someone. Then you go out and murder someone else, should your parents be held legally liable for you murdering someone else? No, they are not. You're a fully grown adult where they have limited authority over even though you may live with them. Now if your parents gave you a gun and said I really hate that person I wish someone would kill them then that would be a different story. Now morally would they still be culpable over you committing a second murder, either way, that is up for each person to decide, but that is not what the law is.
Your illustration is incomplete.
To make a fair comparison, let's say that the parents, after they found out that their son murdered someone again, decided that they weren't going to tell the police. In fact, they weren't going to tell anyone - what would the neighbors think? So, they kept their son's secret.
Now, tell me...are the parents culpable in their son's murder? Are they "accessories after the fact"? Have the parents, by not telling the authorities about the murder, committed a crime themselves?