Virginia Tech shooter Cho Seung-Hui called the Columbine gunmen, Eric Harris and Dylan Klebold, martyrs.
The Columbine shootings in Littleton, Colo., shocked the nation and traumatized those who went through that horrible day when Harris and Klebold killed 12 students and a teacher and wounded 24 others.
But Tom Mauser, who lost his son, Daniel, in the rampage, said he doesn't expect these kind of horrific incidents to stop anytime soon.
"I think that there's a real serious problem in this country with disaffected youth, disturbed students," he told The Early Show co-anchor Russ Mitchell. "I don't think we're doing enough to address it. Unfortunately, I did think it was probably going to happen again."
Brooks Brown, a former Columbine High School student, knew Harris and Klebold and tried to warn authorities that they might carry out a violent act. He sees eerie similarities between Cho and Harris and Klebold.
"When we found out that a year before he had been taken in by the police for stalking, he had mental health issues, he had violent writings that one teacher was willing to resign over if they didn't do something about him," he said. "Aside from the shooting itself, it screams what happened to Eric and Dylan and pretty much the exact events that led up to Columbine."
Brown co-wrote a book on Columbine that argues that Harris and Klebold displayed warning signs that people should have noticed. But in Cho's case, he said there isn't yet enough information to say whether or not people didn't pay close enough attention to his signals.
"I know we can say warning signs were not looked at as strong as they could have been," he said. "This young man was, to use Tom's word, disaffected and in mental trouble for a long time and not a lot of people seemed to give him the attention that he needed in order to get through it without harming himself or others."
Mauser believes that the only way to stop these kinds of incidents is to focus on intervention.
"We have to find something we can do about people like this," he said.
Meanwhile, Mauser went through the grieving process and he said that people who lost loved-ones need to be prepared to face difficult times ahead. They need to understand that people grieve differently and everyone needs to go through the process in their own way. The best thing, he found, was to focus on their loved ones and celebrate their life.
"You know it takes time," he said. "It really does take time. You have lots of ups and downs when you have these shootings ... It just — it takes time and you have to accept that."
Brown also said he suffered in the aftermath of Columbine. He was depressed and was dismayed with the world.
"I was up for days on end, sleeping for days on end," he said. "A friend of my father's gave a quote that I passed on in a couple interviews. This doesn't happen to everyone. So however you grieve is probably right. And that's exactly the truth."
Above all, Mauser said that the most important thing to keep talking.
"Nobody should be quiet during this time," he said. "They really need to talk to each other. Whether that's with a grief counselor. Their child. Their friend. Their neighbor. They really need to talk about it."