"The video — I just lost it," one student told CBS News correspondent Sharyn Alfonsi. "I mostly just wanted to see his face, where his eyes were. But he's just a madman," another said.
That "madman" lived 12 feet away from Karan Grewal — and he did see something he recognized in the video: the walls of his dorm room.
Does he think Cho could have been right there in his dorm room making those videos?
"The backdrop looks exactly like our suite; the chair he is sitting on looks exactly like the one in our suite," Grewal said.
Grewal shared a suite with Cho for the last year.
"It's pretty scary that he was right outside my room taping those videos with guns when I was inside," he told Alfonsi.
Grewal believes Cho had been planning the killings for months. He says he started going to the gym back in February, and all of a sudden started sitting in the common room of the suite — silently watching the roommates come and go.
"It's a really scary feeling that he was out there, monitoring us, plotting the horrific things he did," Grewal said.
And he believes, plotting a time to make the video in private — revealing a madman who masqueraded behind silence.
In Seoul, South Korea. Cho's great aunt says the family was told Cho was autistic when they arrived in America.
"From the very beginning he wouldn't answer me," said Kim Yang Soon, Cho's great aunt, in Korean. "He doesn't talk. He was very cold."
Garrett Evans was in his German class when Cho stormed in.
"He had this face. It was total concentration of what he was doing," Evans said. Today a bullet is lodged in Evans' left leg.
"You know something? I'm blessed," he said. "I am truly, truly blessed because God spared me. I saw the devil at work."
"The first step, the most important step, is to forgive," Evans said. "I forgive the shooter."
That may be the easy part. With images of Cho everywhere, forgetting — even for a second — what happened in Blacksburg now seems impossible.