Transcript for Elliot Rodger's Father on How He Learned His Son Was the Shooter
Now, to an exclusive interview with peter Rodger. The father of Elliot Rodger, who killed six and shot 13 in a rampage near U.C. Santa Barbara last month. Barbara Walters is here. We've never heard from the parent of a shooter. This is the first time a parent of a shooter has sprooken out. We sat down with peter Rodger. And he talked candidly about his struggles with his son, Elliot. He thought his son might be suicidal. But he never thought he would be homicidal. And by the way, he is the first parent to speak out on television. He feels it's his mission. So, we'll take a look. There have been numerous school shootings. None of the parents of other shooters have spoken with us. Why did you decide that you would speak up? The only reason I'm here is to tell his story, to try and stop this happening again. How did you learn that your son was the shooter? I thought he was a victim. And it wasn't until 4:35 A.M. That I found out by going on the internet that he was the main suspect. And there was only one killer. And when I saw that, it was like it's one's worst nightmare. I can't describe the feelings. Mr. Rodger, Elliot was your son. And he is dead. How do you mourn a child whom others vilify? It's very hard, Barbara. It's very, very hard. After Reading the journal, I had a lot of anger for him. And I think my job, now, is to try to replace the anger with love and forgiveness. But at the same time, I'm haunted by this disease, this human being that changed and became something else. The father of Adam Lanza now says there's times he wishes his son had never been born. Do you ever feel that way? That's a really varied question. That's a loaded question, Barbara. A part of me says yes. And the reason is because he did an awful lot of harm to young men and young women who didn't deserve to die. And my son did it. Can you imagine what that feels like? Also, I'm also thinking of the families who lost a loved one. That's right. So is he. So many people are -- warning signs, warning signs. Wanting to know if there were warning signs? That's the big question. The son was an introvert. He didn't have friends. He didn't have girlfriends. He had a lot of problems. He was afraid his son might kill himself. But it never occurred to him that his son would want to kill others. And no matter what the warning signs, how do you know? How do you know? Barbara, good to see you. We will see much more, all of Barbara's interview, with peter Rodger, tonight on "20/20," at 10:00, 9:00 central here on ABC.
This transcript has been automatically generated and may not be 100% accurate.