There are so many reasons why this young man should have been stopped before he got to the point of committing these awful crimes. There are a number of people who failed to act responsibly in dealing with his mental condition.
I was listening to his roommate talk about him. I can’t believe his roommate didn’t think it was off that Cho never talked to him ever! They slept in the same room together and Cho had a blank look on his face every day and never spoke to anyone.
I’m sorry, but if I had a weird roommate like that I’d report the oddness to the school asap.