Please refrain from putting words in my mouth.I don’t really think it’s productive to argue back and forth about it. From your comments it seems you believe they had indication that he was going to do this and they are guilty as charged. That’s perfectly reasonable.
I’m commenting from my perspective as the evidence comes in.
I never once said OR indicated that the parents had an "indication" that their son was going to go on a shooting spree and massacre innocents,