How to put a vassal in prison? (Crusader Kings 3)

One of the vassals, during the hunt rushed with a knife on his son. She was able to prevent the attack, and the vassal escaped. How do I put him in jail? If you choose his character through a map and choose the option of "jailing." then I am given a mole it will be a manifestation of tyranny. He attacked the king's son and heir to the throne, and he can't be imprisoned for that?

P.S turned out to be necessary first to reveal it in the intrigue section, which would be legal to send to the conclusion