Many of you responded with a violent answer to my first hypothetical question but what if the tables were turned?

Hypothetically It’s 11 o’clock at night and your son comes in. He was supposed to be home at 9 so you question where he has been. As you continue talking you pull out of him that he grabbed a knife and threatened to kill an innocent child 12–14 years old. You also find that he had intended to kill her. What would you do?
Now let’s alter the scenario a little as was done in the other question. What if you found out years later?
My guess is no one would kill their child, but I am curios to see your responses. Oh and don’t forget there is a 2–3 year statute of limitations on assault with a deadly weapon.